View source for Lead poisoning

{{Short description|Poisoning caused by lead in the body}}
{{cs1 config|name-list-style=vanc}}
{{Infobox medical condition (new)
| name          = Lead poisoning
| image         = Lead PoisoningRadio.jpg
| caption       = An X-ray demonstrating the characteristic finding of lead poisoning in humans—dense [[metaphyseal]] lines
| field         = [[Toxicology]]
| synonyms      = Plumbism, colica pictorum, saturnism, [[Devon colic]], painter's colic
| symptoms      = [[Intellectual disability]], abdominal pain, [[constipation]], headaches, irritability, memory problems, [[infertility|inability to have children]], [[paresthesia|tingling]] in the hands and feet<ref name=CDC2013Sym/><ref name=WHO2016/>
| complications = [[Anemia]], [[seizures]], [[coma]]<ref name=CDC2013Sym/><ref name=WHO2016/>
| onset         = 
| duration      = 
| types         = 
| causes        = Exposure to [[lead]] via contaminated air, water, dust, food, consumer products<ref name=WHO2016/>
| risks         = Young age, [[Pica (disorder)|pica]]<ref name=WHO2016/>
| diagnosis     = [[Blood lead level]]<ref name=WHO2016/>
| differential  = [[Iron deficiency anemia]], [[malabsorption]], [[ADHD]], [[anxiety disorder]], [[polyneuropathy]]<ref>{{cite book|last1=Ferri|first1=Fred F. |title=Ferri's differential diagnosis : a practical guide to the differential diagnosis of symptoms, signs, and clinical disorders|date=2010|publisher=Elsevier/Mosby|location=Philadelphia, PA|isbn=978-0-323-07699-9|chapter=L|edition=2nd}}</ref>
| prevention    = Removing lead from the home, improved monitoring and education in the workplace, laws that ban lead in products<ref name=WHO2016/><ref name=Dap2014/><ref name=Need2004/><ref name=CDC2016Prev/>
| treatment     = [[Chelation therapy]]<ref name=Dap2014/>
| medication    = [[Dimercaprol]], [[edetate calcium disodium]], [[succimer]]<ref name=Gra2007/>
| prognosis     = 
| frequency     = 
| deaths        = 540,000 (2016)<ref name=WHO2016/>
| alt           = 
}}
<!-- Definition and symptoms -->

'''Lead poisoning''', also known as '''plumbism''' and '''saturnism''', is a type of [[metal poisoning]] caused by [[lead]] in the body.<ref name=WHO2016/> Symptoms may include abdominal pain, [[constipation]], headaches, irritability, memory problems, [[infertility]], numbness and [[paresthesia|tingling]] in the hands and feet.<ref name=CDC2013Sym>{{cite web|title=Lead Information for Workers |url=https://www.cdc.gov/niosh/topics/lead/health.html |website=CDC|access-date=14 October 2016|date=30 September 2013|url-status=live|archive-url=https://web.archive.org/web/20161018215410/http://www.cdc.gov/niosh/topics/lead/health.html|archive-date=18 October 2016}}</ref> It causes almost 10% of [[intellectual disability]] of otherwise unknown cause and can result in behavioral problems.<ref name=WHO2016/> Some of the effects are permanent.<ref name=WHO2016/> In severe cases, [[anemia]], [[seizures]], [[coma]], or [[death]] may occur.<ref name=CDC2013Sym/><ref name=WHO2016/>

<!-- Exposure and diagnosis -->
Exposure to lead can occur through contaminated air, water, dust, food, or consumer products.<ref name=WHO2016/> Lead poisoning poses a significantly increased risk to children and pets as they are far more likely to ingest lead indirectly by chewing on toys or other objects that are coated in [[lead paint]].<ref name=WHO2016/> Additionally, children absorb greater quantities of lead from ingested sources than adults. Exposure at work is a common cause of lead poisoning in adults, with certain occupations at particular risk.<ref name=Gra2007/> Diagnosis is typically by measurement of the [[blood lead level]].<ref name=WHO2016>{{cite web|title=Lead poisoning and health|url=https://www.who.int/mediacentre/factsheets/fs379/en/|website=WHO|access-date=14 October 2016|date=September 2016|url-status=live|archive-url=https://web.archive.org/web/20161018024720/http://www.who.int/mediacentre/factsheets/fs379/en/|archive-date=18 October 2016}}</ref> The [[Centers for Disease Control and Prevention]] (US) has set the upper limit for blood lead for adults at 10&nbsp;μg/dL (10&nbsp;μg/100 g) and for children at 3.5&nbsp;μg/dL;<ref name=CDC2021>{{cite web |url=https://www.cdc.gov/media/releases/2021/p1028-blood-lead.html |title=CDC Updates Blood Lead Reference Value for Children |publisher=[[Centers for Disease Control and Prevention]] |date=28 October 2021 |url-status=dead |archive-url=https://web.archive.org/web/20230922075339/https://www.cdc.gov/media/releases/2021/p1028-blood-lead.html |archive-date= Sep 22, 2023 }}</ref> before October 2021 the limit was 5&nbsp;μg/dL.<ref name="CDC2012">{{cite web|date=2021-10-28|title=Blood Lead Reference Value {{!}} Lead |url=https://www.cdc.gov/nceh/lead/data/blood-lead-reference-value.htm|access-date=2021-12-01 |publisher=[[Centers for Disease Control and Prevention]] |language=en-us}}</ref><ref>{{cite book|title=The Code of Federal Regulations of the United States of America|date=2005|publisher=U.S. Government Printing Office|page=116|url=https://books.google.com/books?id=sb06AAAAIAAJ&pg=PA116|url-status=live|archive-url=https://web.archive.org/web/20171105194927/https://books.google.com/books?id=sb06AAAAIAAJ&pg=PA116|archive-date=2017-11-05}}</ref> Elevated lead may also be detected by changes in [[red blood cell]]s or dense lines in the bones of children as seen on [[X-ray]].<ref name=Dap2014>{{cite journal | vauthors = Dapul H, Laraque D | title = Lead poisoning in children | journal = Advances in Pediatrics | volume = 61 | issue = 1 | pages = 313–33 | date = August 2014 | pmid = 25037135 | doi = 10.1016/j.yapd.2014.04.004 }}</ref>

<!-- Prevention and treatment  -->
Lead poisoning is preventable.<ref name=WHO2016/> This includes individual efforts such as removing lead-containing items from the home,<ref name=Need2004/> workplace efforts such as improved ventilation and monitoring,<ref name=CDC2016Prev>{{cite web|title=Lead Information for Employers|url=https://www.cdc.gov/niosh/topics/lead/prevention.html|website=CDC|access-date=14 October 2016|date=30 September 2013|url-status=live|archive-url=https://web.archive.org/web/20161018210747/http://www.cdc.gov/niosh/topics/lead/prevention.html|archive-date=18 October 2016}}</ref> state and national policies that ban lead in products such as paint, gasoline, ammunition, wheel weights, and fishing weights, reduce allowable levels in water or soil, and provide for cleanup of contaminated soil.<ref name=WHO2016/><ref name=Dap2014/> Workers' education could be helpful as well.<ref name=":0">{{cite journal|last=Allaouat|first=Sarah|year=2020|title=Educational interventions for preventing lead poisoning in workers. Cochrane Database of Systematic Reviews 2020|journal=Cochrane Database of Systematic Reviews|volume=2020|issue=8|page=CD013097|doi=10.1002/14651858.CD013097.pub2|pmid=35819457 |pmc=8095058|s2cid=226951902}}</ref> The major treatments are removal of the source of lead and the use of medications that bind lead so it can be [[excretion|eliminated from the body]], known as [[chelation therapy]].<ref name=Dap2014/> Chelation therapy in children is recommended when blood levels are greater than 40–45&nbsp;μg/dL.<ref name=Dap2014/><ref>{{cite web|title=What Do Parents Need to Know to Protect Their Children?|url=https://www.cdc.gov/nceh/lead/acclpp/blood_lead_levels.htm|website=CDC|access-date=14 October 2016|date=30 October 2012|url-status=live|archive-url=https://web.archive.org/web/20161009233521/http://www.cdc.gov/nceh/lead/acclpp/blood_lead_levels.htm|archive-date=9 October 2016}}</ref> Medications used include [[dimercaprol]], [[edetate calcium disodium]], and [[succimer]].<ref name=Gra2007>{{cite journal | vauthors = Gracia RC, Snodgrass WR | title = Lead toxicity and chelation therapy | journal = American Journal of Health-System Pharmacy | volume = 64 | issue = 1 | pages = 45–53 | date = January 2007 | pmid = 17189579 | doi = 10.2146/ajhp060175 }}</ref>

<!-- Epidemiology and history -->
In 2021, 1.5 million deaths worldwide were attributed to lead exposure.<ref>{{Cite web |title=Lead poisoning |url=https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health |access-date=2024-12-06 |website=www.who.int |language=en}}</ref> It occurs most commonly in the [[developing world]].<ref name=WHO2016/> An estimated 800 million children have blood lead levels over 5 μg/dL in low- and middle-income nations, though comprehensive public health data remains inadequate.<ref>{{Cite journal |last1=Champion |first1=Wyatt M. |last2=Khaliq |first2=Mahmooda |last3=Mihelcic |first3=James R. |date=2022-11-08 |title=Advancing Knowledge to Reduce Lead Exposure of Children in Data-Poor Low- and Middle-Income Countries |url=https://pubs.acs.org/doi/abs/10.1021/acs.estlett.2c00656 |journal=Environmental Science & Technology Letters |volume=9 |issue=11 |pages=879–888 |doi=10.1021/acs.estlett.2c00656|bibcode=2022EnSTL...9..879C |url-access=subscription }}</ref> Thousands of American communities may have higher lead burdens than those seen during the peak of the [[Flint water crisis]].<ref>{{cite web |last1=Laborers' Health and Safety Fund of North America |title=Thousands of US Cities Have Worse Lead Problems Than Flint |date=11 February 2017 |url=https://www.lhsfna.org/index.cfm/lifelines/february-2017/thousands-of-u-s-cities-have-worse-lead-problems-than-flint/ |access-date=26 September 2021 |archive-date=26 September 2021 |archive-url=https://web.archive.org/web/20210926145557/https://www.lhsfna.org/index.cfm/lifelines/february-2017/thousands-of-u-s-cities-have-worse-lead-problems-than-flint/ |url-status=dead }}</ref> Those who are poor are at greater risk.<ref name=WHO2016/> Lead is believed to result in 0.6% of the world's [[disease burden]].<ref name=Need2004/> Half of the US population has been exposed to substantially detrimental lead levels in early childhood, mainly from car exhaust, from which lead pollution peaked in the 1970s and caused widespread loss in cognitive ability.<ref>{{cite news |title=Lead exposure in last century shrunk IQ scores of half of Americans |url=https://medicalxpress.com/news/2022-03-exposure-century-shrunk-iq-scores.html |access-date=18 April 2022 |work=Duke University |language=en}}</ref><ref>{{cite journal |last1=McFarland |first1=Michael J. |last2=Hauer |first2=Matt E. |last3=Reuben |first3=Aaron |title=Half of US population exposed to adverse lead levels in early childhood |journal=Proceedings of the National Academy of Sciences |date=15 March 2022 |volume=119 |issue=11 |pages=e2118631119 |doi=10.1073/pnas.2118631119|doi-access=free | pmid=35254913  |pmc=8931364 |bibcode=2022PNAS..11918631M |language=en |issn=0027-8424}}</ref> Globally, over 15% of children are known to have blood lead levels (BLL) of over 10 μg/dL, at which point clinical intervention is strongly indicated.<ref>{{Cite journal |last1=Dissanayake |first1=Vinodinee |last2=Erickson |first2=Timothy B. |date=29 Jun 2012 |title=Ball and chain: The global burden of lead poisoning |url=https://www.tandfonline.com/doi/full/10.3109/15563650.2012.698018 |journal=Clinical Toxicology |volume=50 |issue=6 |pages=528–531 |doi=10.3109/15563650.2012.698018 |pmid=22746385 |via=Taylor & Francis Online|url-access=subscription }}</ref>

People have been mining and using lead for thousands of years.<ref name=Dap2014/> Descriptions of lead poisoning date to at least 200&nbsp;BC,<ref name=Dap2014/> while efforts to limit lead's use date back to at least the 16th century.<ref name=Need2004>{{cite journal | vauthors = Needleman H | title = Lead poisoning | journal = Annual Review of Medicine | volume = 55 | pages = 209–22 | year = 2004 | pmid = 14746518 | doi = 10.1146/annurev.med.55.091902.103653 }}</ref> Concerns for low levels of exposure began in the 1970s, with there being no safe threshold for lead exposure.<ref name=WHO2016/><ref name=Dap2014/><ref name="NeedlemanDentineLead">{{cite journal |last1=Needleman |first1=Herbert L. |last2=Gunnoe |first2=Charles |last3=Leviton |first3=Alan |last4=Reed |first4=Robert |last5=Peresie |first5=Henry |last6=Maher |first6=Cornelius |last7=Barrett |first7=Peter |title=Deficits in Psychologic and Classroom Performance of Children with Elevated Dentine Lead Levels |journal=New England Journal of Medicine |date=29 March 1979 |volume=300 |issue=13 |pages=689–695 |doi=10.1056/NEJM197903293001301 |pmid=763299 |access-date=17 November 2020|url=https://www.nejm.org/doi/full/10.1056/NEJM197903293001301|url-access=subscription }}</ref>

{{TOC limit|3}}

==Classification==
<!-- DEFINITIONS -->
Classically, "lead poisoning" or "lead intoxication" has been defined as exposure to high levels of lead, typically associated with severe health effects.<ref name="Grant09-785">[[#CITEREFGrant09|Grant (2009)]] p. 785</ref> Poisoning is a pattern of symptoms that occur with toxic effects from mid to high levels of exposure; toxicity is a wider spectrum of effects, including [[subclinical]] ones (those that do not cause symptoms).<ref name="Guidotti07-PedClin">{{cite journal | vauthors = Guidotti TL, Ragain L | title = Protecting children from toxic exposure: three strategies | journal = Pediatric Clinics of North America | volume = 54 | issue = 2 | pages = 227–35, vii | date = April 2007 | pmid = 17448358 | doi = 10.1016/j.pcl.2007.02.002 | citeseerx = 10.1.1.533.907 }}</ref> However, professionals often use "lead poisoning" and "lead toxicity" interchangeably, and official sources do not always restrict the use of "lead poisoning" to refer only to symptomatic effects of lead.<ref name="Guidotti07-PedClin"/>

The amount of lead in the blood and tissues, as well as the time course of exposure, determine toxicity.<ref name="Pearson03"/>
<!-- ACUTE VS. CHRONIC -->
Lead poisoning may be acute (from intense exposure of short duration) or chronic (from repeated low-level exposure over a prolonged period), but the latter is much more common.<ref name="Trevor07-479">[[#CITEREFTrevor07|Trevor, Katzung, Masters (2007)]] p. 479</ref>
<!-- BLOOD LEVELS -->
Diagnosis and treatment of lead exposure are based on blood lead level (the amount of lead in the blood), measured in [[microgram]]s of lead per [[deciliter]] of blood (μg/dL). Urine lead levels may be used, though less commonly. In cases of chronic exposure, lead often sequesters in the highest concentrations first in the bones, then in the kidneys. If a provider is performing a provocative excretion test, or "chelation challenge", a measurement obtained from urine rather than blood is likely to provide a more accurate representation of total lead burden to a skilled interpreter.<ref name="who.int">{{cite web | last = Lowry | first = Jennifer A. | date = 2010 | url =https://www.who.int/selection_medicines/committees/expert/18/applications/4_2_LeadOralChelators.pdf | title = Oral Chelation Therapy for Patients with Lead Poisoning | archive-url = https://web.archive.org/web/20160126141333/http://www.who.int/selection_medicines/committees/expert/18/applications/4_2_LeadOralChelators.pdf | archive-date = 2016-01-26 | work = WHO}}</ref>

The US [[Centers for Disease Control and Prevention]] and the [[World Health Organization]] state that a blood lead level of 10&nbsp;μg/dL or above is a cause for concern; however, lead may impair development and have harmful health effects even at lower levels, and there is no known safe exposure level.<ref name="Rossi09"/><ref name="Barbosa">{{cite journal | vauthors = Barbosa F, Tanus-Santos JE, Gerlach RF, Parsons PJ | title = A critical review of biomarkers used for monitoring human exposure to lead: advantages, limitations, and future needs | journal = Environmental Health Perspectives | volume = 113 | issue = 12 | pages = 1669–74 | date = December 2005 | pmid = 16330345 | pmc = 1314903 | doi = 10.1289/ehp.7917 | bibcode = 2005EnvHP.113.1669B }}</ref> Authorities such as the American Academy of Pediatrics define lead poisoning as blood lead levels higher than 10&nbsp;μg/dL.<ref name="Ragan09-JAAPA"/>

<!-- ORGANIC VS. INORGANIC -->
Lead forms a variety of compounds and exists in the environment in various forms.<ref name="Grant09-761">[[#CITEREFGrant09|Grant (2009)]] p. 761</ref> Features of poisoning differ depending on whether the agent is an [[organic compound]] (one that contains carbon), or an [[inorganic]] one.<ref name="Katzung07-948"/> Organic lead poisoning is now very rare, because countries across the world have phased out the use of organic [[gasoline#Tetraethyl lead|lead compounds as gasoline additives]]. These compounds are still used in industrial settings.<ref name="Katzung07-948"/> Organic lead compounds, which cross the skin and respiratory tract easily, affect the [[central nervous system]] predominantly.<ref name="Katzung07-948"/>

==Signs and symptoms==
[[File:Symptoms of lead poisoning (raster).png|thumb|upright=1.3|Symptoms of lead poisoning]]
<!-- ABOUT S/S -->
Lead poisoning can cause a variety of [[symptom]]s and [[medical sign|signs]] which vary depending on the individual and the duration of lead exposure.<ref name="Karri08"/><ref name="Kosnett05-825"/> Symptoms are nonspecific and may be subtle, and someone with elevated lead levels may have no symptoms.<ref name="Mycyk05-463"/> Symptoms usually develop over weeks to months as lead builds up in the body during a chronic exposure, but acute symptoms from brief, intense exposures also occur.<ref name="Dart041426"/>
<!-- ORGANIC LEAD -->
Symptoms from exposure to organic lead, which is probably more toxic than inorganic lead due to its lipid solubility, occur rapidly.<ref name="Timbrell08">{{cite book |title= Principles of Biochemical Toxicology |edition=4th |chapter=Biochemical mechanisms of toxicity: Specific examples | veditors = Timbrell JA |year= 2008 |publisher=Informa Health Care |isbn= 978-0-8493-7302-2}}</ref> Poisoning by organic lead compounds has symptoms predominantly in the central nervous system, such as [[insomnia]], [[delirium]], [[cognitive deficit]]s, [[tremor]], [[hallucinations]], and convulsions.<ref name="Katzung07-948"/>

<!--
CHILDREN V. ADULTS-->
Symptoms may be different in adults and children; the main symptoms in adults are headache, [[abdominal pain]], [[memory loss]], [[kidney failure]], male reproductive problems, and weakness, pain, or tingling in the extremities.<ref name="Pearce07-EurNeurol">{{cite journal | vauthors = Pearce JM | title = Burton's line in lead poisoning | journal = European Neurology | volume = 57 | issue = 2 | pages = 118–9 | year = 2007 | pmid = 17179719 | doi = 10.1159/000098100 | s2cid = 41427430 | doi-access = free }}</ref>

Early symptoms of lead poisoning in adults are commonly nonspecific and include depression, loss of appetite, intermittent abdominal pain, nausea, diarrhea, constipation, and [[myalgia|muscle pain]].<ref name="Merrill07"/> Other early signs in adults include [[malaise]], fatigue, decreased [[libido]], and problems with sleep.<ref name="Karri08"/> An unusual taste in the mouth and personality changes are also early signs.<ref name="Patrick06"/><ref>{{cite web |url=https://edhub.ama-assn.org/jn-learning/video-player/17844517 |title=Childhood Lead Exposure, Adult Personality, and Later-Life Mental Health |author=<!--Not stated--> |date=3 September 2019 |website=AMA Ed Hub |publisher=JN Learning |access-date=13 December 2020 |quote=This JAMA Medical News video summarizes findings from a recent cohort study reporting an association between childhood lead exposure in Dunedin, New Zealand, and adult personality traits and psychopathology.}}</ref>

In adults, symptoms can occur at levels above 40&nbsp;μg/dL, but are more likely to occur only above 50–60&nbsp;μg/dL.<ref name="Karri08"/> Symptoms begin to appear in children generally at around 60&nbsp;μg/dL.<ref name=Need2004/> However, the lead levels at which symptoms appear vary widely depending on unknown characteristics of each individual.<ref name="Bellinger04-Pedi"/> At blood lead levels between 25 and 60&nbsp;μg/dL, [[neuropsychiatric]] effects such as delayed [[reaction time]]s, irritability, and difficulty concentrating, as well as slowed [[motor nerve]] conduction and headache can occur.<ref name="Kosnett06-240">[[#CITEREFKosnett06Pois|Kosnett (2006)]] p.240</ref> [[Anemia]] may appear at blood lead levels higher than 50&nbsp;μg/dL.<ref name="Merrill07"/> In adults, abdominal [[colic]], involving [[Paroxysmal attack|paroxysm]]s of pain, may appear at blood lead levels greater than 80&nbsp;μg/dL.<ref name="Kosnett05-825">[[#CITEREFKosnett05|Kosnett (2005)]] p. 825</ref> Signs that occur in adults at blood lead levels exceeding 100&nbsp;μg/dL include [[wrist drop]] and [[foot drop]], <!-- because of neuropathy --> and signs of [[encephalopathy]] (a condition characterized by [[cerebral edema|brain swelling]]), such as those that accompany increased [[intracranial pressure|pressure within the skull]], delirium, coma, [[seizures]], and [[headache]].<ref name="Henretig061314">[[#CITEREFHenretig06|Henretig (2006)]] p. 1314</ref> In children, signs of encephalopathy such as bizarre behavior, discoordination, and apathy occur at lead levels exceeding 70&nbsp;μg/dL.<ref name="Henretig061314"/> For both adults and children, it is rare to be asymptomatic if blood lead levels exceed 100&nbsp;μg/dL.<ref name="Kosnett05-825"/>

===Acute poisoning===
In acute poisoning, typical neurological signs are pain, muscle weakness, [[paresthesia|numbness and tingling]], and, rarely, symptoms associated with [[encephalitis|inflammation of the brain]].<ref name="Pearce07-EurNeurol"/> Abdominal pain, nausea, vomiting, diarrhea, and constipation are other acute symptoms.<ref name="Brunton07-31"/> Lead's effects on the mouth include [[astringent|astringency]] and a metallic taste.<ref name="Brunton07-31"/> [[Gastrointestinal problem]]s, such as [[constipation]], [[diarrhea]], [[poor appetite]], or [[weight loss]], are common in acute poisoning. Absorption of large amounts of lead over a short time can cause [[Shock (circulatory)|shock]] (insufficient fluid in the [[circulatory system]]) due to loss of water from the gastrointestinal tract.<ref name="Brunton07-31"/> [[Hemolysis]] (the rupture of [[red blood cells]]) due to acute poisoning can cause [[anemia]] and [[hemoglobinuria|hemoglobin in the urine]].<ref name="Brunton07-31"/> Damage to kidneys can cause changes in urination such as acquired [[Fanconi syndrome]] and [[oliguria|decreased urine output]].<ref name="Brunton07-31"/> People who survive acute poisoning often go on to display symptoms of chronic poisoning.<ref name="Brunton07-31"/>

===Chronic poisoning===
Chronic poisoning usually presents with symptoms affecting multiple systems,<ref name="Katzung07-948"/> but is associated with three main types of symptoms: [[gastrointestinal]], [[neuromuscular]], and [[neurological]].<ref name="Pearce07-EurNeurol"/> [[Central nervous system]] and neuromuscular symptoms usually result from intense exposure, while gastrointestinal symptoms usually result from exposure over longer periods.<ref name="Brunton07-31"/> Signs of chronic exposure include loss of [[short-term memory]] or concentration, depression, nausea, abdominal pain, loss of coordination, and numbness and tingling in the extremities.<ref name="Patrick06"/>{{ums|date=December 2017}} Fatigue, problems with sleep, headaches, stupor, slurred speech, and anemia are also found in chronic lead poisoning.<ref name="Pearce07-EurNeurol"/> A "lead hue" of the skin with [[pallor]] and/or [[lividity]] is another feature<!--of chronic lead poisoning-->.<ref name="Andrews">{{cite book | last1 = James | first1 = William | last2 = Berger | first2 = Timothy | last3 = Elston | first3 = Dirk | date = 2005 | title = Andrews' Diseases of the Skin: Clinical Dermatology | edition = 10th | publisher = Saunders | isbn = 0-7216-2921-0 | page = 859}}</ref><ref name="El SafouryAbd El Fatah2009">{{cite journal | vauthors = El Safoury OS, El Fatah DS, Ibrahim M | title = Treatment of periocular hyperpigmentation due to lead of kohl (surma) by penicillamine: a single group non-randomized clinical trial | journal = Indian Journal of Dermatology | volume = 54 | issue = 4 | pages = 361–3 | year = 2009 | pmid = 20101339 | pmc = 2807714 | doi = 10.4103/0019-5154.57614 | doi-access = free }}</ref> A blue line along the gum with bluish black edging to the teeth, known as a [[Burton line]], is another indication of chronic lead poisoning.<ref name="Rambousek08-177">[[#CITEREFRambousek08|Rambousek (2008)]] p.177</ref> Children with chronic poisoning may refuse to play or may have [[Hyperkinetic disorder|hyperkinetic]] or aggressive behavior disorders.<ref name="Pearce07-EurNeurol"/> Visual disturbance may present with gradually progressing blurred vision as a result of central [[scotoma]], caused by toxic [[optic neuritis]].<ref>{{cite web|last1=Fintak|first1=David R. |title=Wills Eye Resident Case Series|date=30 January 2007|url=http://www.revophth.com/content/d/wills_resident_case_series/i/1297/c/24966/|url-status=live|archive-url=https://web.archive.org/web/20140714181927/http://www.revophth.com/content/d/wills_resident_case_series/i/1297/c/24966/|archive-date=14 July 2014}}</ref>

===Effects on children===
[[File:Fewer US kids Have High Levels of Lead.svg|thumb|upright=1.4|As lead safety standards become more stringent, fewer children in the US are found to have elevated lead levels.]]
A pregnant woman who has elevated blood lead levels is at greater risk of a premature birth or a low birth weight.<ref>{{cite book|last1=Kappy|first1=Michael S. |title=Advances in Pediatrics, E-Book|date=2015|publisher=Elsevier Health Sciences|isbn=978-0-323-26462-4|page=320|url=https://books.google.com/books?id=8G-KCwAAQBAJ&pg=PA320|url-status=live|archive-url=https://web.archive.org/web/20171030042508/https://books.google.ca/books?id=8G-KCwAAQBAJ&pg=PA320|archive-date=2017-10-30}}</ref> Children are more at risk for lead poisoning because their smaller bodies are in a continuous state of growth and development.<ref name="autogenerated2002">{{cite journal | vauthors = Landrigan PJ, Schechter CB, Lipton JM, Fahs MC, Schwartz J | title = Environmental pollutants and disease in American children: estimates of morbidity, mortality, and costs for lead poisoning, asthma, cancer, and developmental disabilities | journal = Environmental Health Perspectives | volume = 110 | issue = 7 | pages = 721–8 | date = July 2002 | pmid = 12117650 | pmc = 1240919 | doi = 10.1289/ehp.02110721 | bibcode = 2002EnvHP.110..721L }}</ref> Young children are much more vulnerable to lead poisoning, as they absorb 4 to 5 times more lead than an adult from a given source.<ref>{{cite web|title=Lead poisoning and health|url=https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health|access-date=2020-11-28|website=www.who.int}}</ref> Furthermore, children, especially as they are learning to crawl and walk, are constantly on the floor and therefore more prone to ingesting and inhaling dust that is contaminated with lead.<ref name="Woolf07-PedClin"/>

The classic signs and symptoms in children are loss of appetite, abdominal pain, vomiting, weight loss, constipation, anemia, kidney failure, irritability, lethargy, learning disabilities, and behavioral problems.<ref name="autogenerated2">{{cite web | url = http://www.ecy.wa.gov/programs/hwtr/demodebris/pages2/lbloodtest.html | title = Blood Lead Level Testing | archive-url = https://web.archive.org/web/20160204012907/http://www.ecy.wa.gov/programs/hwtr/demodebris/pages2/lbloodtest.html | archive-date = 2016-02-04 | work = Department of Ecology State of Washington | date = 2011 }}</ref> Slow development of normal childhood behaviors, such as talking and use of words, and permanent [[intellectual disability]] are both commonly seen. Although less common, fingernails can develop [[leukonychia#Leukonychia striata|leukonychia striata]] if exposed to abnormally high lead concentrations.<ref>{{cite book |last1=Baran |first1=Robert |last2=de Berker |first2=David A. R. |last3=Holzberg |first3=Mark |last4=Thomas |first4=Luc |title=Baran and Dawber's Diseases of the Nails and their Management|date=2012|publisher=John Wiley & Sons|isbn=978-1-118-28670-8|page=417|url=https://books.google.com/books?id=ekr4Bt683c8C&pg=PT417}}</ref>

On July 30, 2020, a report by [[UNICEF]] and [[Pure Earth]] revealed that lead poisoning is affecting children on a "massive and previously unknown scale". According to the report, one in three children, up to 800 million globally, have blood lead levels at or above 5 micrograms per decilitre (μg/dL), which is the commonly-accepted threshold beyond which action is required.<ref>{{cite web|url=https://news.un.org/en/story/2020/07/1069251|title=Revealed: A third of world's children poisoned by lead, UNICEF analysis finds|access-date=30 July 2020|website=UN News|date=29 July 2020}}</ref><ref>{{cite web|url=https://www.unicef.org/sites/default/files/2020-07/The-toxic-truth-children%E2%80%99s-exposure-to-lead-pollution-2020.pdf|title=The Toxic Truth: Children's Exposure to Lead Pollution Undermines a Generation of Future Potential|access-date=30 July 2020|website=UNICEF}}</ref>

===By organ system===
Lead affects every one of the body's organ systems, especially the nervous system, but also the bones and teeth, the kidneys, and the [[cardiovascular system|cardiovascular]], [[immune system|immune]], and [[reproductive system]]s.<ref name="White07"/> [[Hearing loss]] and [[tooth decay]] have been linked to lead exposure,<ref name="Lanphear05EnvironHealth">{{cite journal | vauthors = Lanphear BP, Hornung R, Khoury J, Yolton K, Baghurst P, Bellinger DC, Canfield RL, Dietrich KN, Bornschein R, Greene T, Rothenberg SJ, Needleman HL, Schnaas L, Wasserman G, Graziano J, Roberts R | title = Low-level environmental lead exposure and children's intellectual function: an international pooled analysis | journal = Environmental Health Perspectives | volume = 113 | issue = 7 | pages = 894–9 | date = July 2005 | pmid = 16002379 | pmc = 1257652 | doi = 10.1289/ehp.7688 | bibcode = 2005EnvHP.113..894L }}</ref> as have [[cataracts]].<ref name="Pokras08-Ecohealth"/> Intrauterine and neonatal lead exposure promote tooth decay.<ref>{{cite journal | vauthors = Brudevold F, Steadman LT | title = The distribution of lead in human enamel | journal = Journal of Dental Research | volume = 35 | issue = 3 | pages = 430–7 | date = June 1956 | pmid = 13332147 | doi = 10.1177/00220345560350031401 | s2cid = 5453470 }}</ref><ref>{{cite journal | vauthors = Brudevold F, Aasenden R, Srinivasian BN, Bakhos Y | title = Lead in enamel and saliva, dental caries and the use of enamel biopsies for measuring past exposure to lead | journal = Journal of Dental Research | volume = 56 | issue = 10 | pages = 1165–71 | date = October 1977 | pmid = 272374 | doi = 10.1177/00220345770560100701 | s2cid = 37185511 }}</ref><ref>{{cite journal | vauthors = Goyer RA | title = Transplacental transport of lead | journal = Environmental Health Perspectives | volume = 89 | pages = 101–5 | date = November 1990 | pmid = 2088735 | pmc = 1567784 | doi = 10.2307/3430905 | jstor = 3430905 }}</ref><ref>{{cite journal | vauthors = Moss ME, Lanphear BP, Auinger P | title = Association of dental caries and blood lead levels | journal = JAMA | volume = 281 | issue = 24 | pages = 2294–8 | year = 1999 | pmid = 10386553 | doi = 10.1001/jama.281.24.2294 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Campbell JR, Moss ME, Raubertas RF | title = The association between caries and childhood lead exposure | journal = Environmental Health Perspectives | volume = 108 | issue = 11 | pages = 1099–102 | date = November 2000 | pmid = 11102303 | pmc = 1240169 | doi = 10.2307/3434965 | jstor = 3434965 }}</ref><ref>{{cite journal | vauthors = Gemmel A, Tavares M, Alperin S, Soncini J, Daniel D, Dunn J, Crawford S, Braveman N, Clarkson TW, McKinlay S, Bellinger DC | title = Blood lead level and dental caries in school-age children | journal = Environmental Health Perspectives | volume = 110 | issue = 10 | pages = A625-30 | date = October 2002 | pmid = 12361944 | pmc = 1241049 | doi = 10.1289/ehp.021100625 }}</ref><ref>{{cite journal | vauthors = Billings RJ, Berkowitz RJ, Watson G | title = Teeth | journal = Pediatrics | volume = 113 | issue = 4 Suppl | pages = 1120–7 | date = April 2004 | doi = 10.1542/peds.113.S3.1120 | pmid = 15060208 | url = https://pediatrics.aappublications.org/content/113/Supplement_3/1120.long | url-access = subscription }}</ref> Aside from the developmental effects unique to young children, the health effects experienced by adults are similar to those in children, although the thresholds are generally higher.<ref>{{cite web |author=Agency for Toxic Substances and Disease Registry |url=https://www.atsdr.cdc.gov/csem/csem.html |title=Lead Toxicity: Who Is at Risk of Lead Exposure? |work=Environmental Health and Medicine Education |publisher=U.S. Department of Health and Human Services |id=Course: WB 1105 |date=August 20, 2007 |url-status=live |archive-url=https://web.archive.org/web/20160204174821/http://www.atsdr.cdc.gov/csem/csem.asp?csem=7&po=7 |archive-date=February 4, 2016 }}</ref>

====Kidneys====
Kidney damage occurs with exposure to high levels of lead, and evidence suggests that lower levels can damage kidneys as well.<ref name="Grant09-789">[[#CITEREFGrant09|Grant (2009)]] p. 789</ref> The toxic effect of lead causes [[nephropathy]] and may cause [[Fanconi syndrome]], in which the [[proximal tubule|proximal tubular]] function of the kidney is impaired.<ref name="Rubin08-267">[[#CITEREFRubin08|Rubin, Strayer (2008)]] p. 267</ref> Long-term exposure at levels lower than those that cause lead nephropathy have also been reported as [[nephrotoxicity|nephrotoxic]] in patients from developed countries that had chronic kidney disease or were at risk because of hypertension or [[diabetes mellitus]].<ref name="Ekong06KidneyInt">{{cite journal | vauthors = Ekong EB, Jaar BG, Weaver VM | title = Lead-related nephrotoxicity: a review of the epidemiologic evidence | journal = Kidney International | volume = 70 | issue = 12 | pages = 2074–84 | date = December 2006 | pmid = 17063179 | doi = 10.1038/sj.ki.5001809 | s2cid = 2043132 | doi-access = free }}</ref>
<!--
GOUT -->Lead poisoning inhibits excretion of the waste product [[uric acid|urate]] and causes a predisposition for [[gout]], in which urate builds up.<ref name="Wright83JReum">{{cite journal | vauthors = Wright LF, Saylor RP, Cecere FA | title = Occult lead intoxication in patients with gout and kidney disease | journal = The Journal of Rheumatology | volume = 11 | issue = 4 | pages = 517–20 | date = August 1984 | pmid = 6434739 }}</ref><ref name="pmid8035397">{{cite journal | vauthors = Lin JL, Huang PT | title = Body lead stores and urate excretion in men with chronic renal disease | journal = The Journal of Rheumatology | volume = 21 | issue = 4 | pages = 705–9 | date = April 1994 | pmid = 8035397 }}</ref><ref name="pmid10914856">{{cite journal | vauthors = Shadick NA, Kim R, Weiss S, Liang MH, Sparrow D, Hu H | title = Effect of low level lead exposure on hyperuricemia and gout among middle aged and elderly men: the normative aging study | journal = The Journal of Rheumatology | volume = 27 | issue = 7 | pages = 1708–12 | date = July 2000 | pmid = 10914856 }}</ref> This condition is known as ''saturnine gout''.

====Cardiovascular system====
Evidence suggests lead exposure is associated with [[hypertension|high blood pressure]], and studies have also found connections between lead exposure and [[coronary artery|coronary]] [[heart disease]], [[heart rate variability]], and death from stroke, but this evidence is more limited.<ref name="Navas-Acien06">{{cite journal | vauthors = Navas-Acien A, Guallar E, Silbergeld EK, Rothenberg SJ | title = Lead exposure and cardiovascular disease--a systematic review | journal = Environmental Health Perspectives | volume = 115 | issue = 3 | pages = 472–82 | date = March 2007 | pmid = 17431501 | pmc = 1849948 | doi = 10.1289/ehp.9785 | bibcode = 2007EnvHP.115..472N }}</ref> People who have been exposed to higher concentrations of lead may be at a higher risk for cardiac [[autonomic dysfunction]] on days when [[ozone]] and fine particles are higher.<ref name="Park09Epidem">{{cite journal | vauthors = Park SK, O'Neill MS, Vokonas PS, Sparrow D, Wright RO, Coull B, Nie H, Hu H, Schwartz J | title = Air pollution and heart rate variability: effect modification by chronic lead exposure | journal = Epidemiology | volume = 19 | issue = 1 | pages = 111–20 | date = January 2008 | pmid = 18091001 | pmc = 2671065 | doi = 10.1097/EDE.0b013e31815c408a }}</ref>

====Reproductive system====
Lead affects both the male and female reproductive systems. In men, when blood lead levels exceed 40&nbsp;μg/dL, [[sperm count]] is reduced and changes occur in volume of sperm, their [[motility]], and their [[Morphology (biology)|morphology]].<ref name="Grant09-792">[[#CITEREFGrant09|Grant (2009)]] p. 792</ref>
A pregnant woman's elevated blood lead level can lead to [[miscarriage]], [[Preterm birth|prematurity]], low [[birth weight]], and problems with development during childhood.<ref name="Cleveland08"/> Lead can pass through the [[placenta]] and into [[breast milk]], and blood lead levels in mothers and infants are usually similar.<ref name="Dart041426"/> A fetus may be poisoned ''in utero'' if lead from the mother's bones is subsequently mobilized by the changes in metabolism due to pregnancy; increased calcium intake in pregnancy may help mitigate this phenomenon.<ref name="Bellinger05BirthDef">{{cite journal | vauthors = Bellinger DC | title = Teratogen update: lead and pregnancy | journal = Birth Defects Research. Part A, Clinical and Molecular Teratology | volume = 73 | issue = 6 | pages = 409–20 | date = June 2005 | pmid = 15880700 | doi = 10.1002/bdra.20127 | doi-access = free }}</ref>

====Nervous system====
[[File:Decreased Brain Volume from Lead Exposure.jpg|thumb|The brains of adults who were exposed to lead as children show decreased volume, especially in the [[prefrontal cortex]], on [[magnetic resonance imaging|MRI]]. Areas of volume loss are shown in color over a template of a normal brain.<ref name="Cecil08">{{cite journal | vauthors = Cecil KM, Brubaker CJ, Adler CM, Dietrich KN, Altaye M, Egelhoff JC, Wessel S, Elangovan I, Hornung R, Jarvis K, Lanphear BP | title = Decreased brain volume in adults with childhood lead exposure | journal = PLOS Medicine | volume = 5 | issue = 5 | page = e112 | date = May 2008 | pmid = 18507499 | pmc = 2689675 | doi = 10.1371/journal.pmed.0050112 | veditors = Balmes J | doi-access = free }}</ref>|alt=Eight MRI views of a brain in black and white, with yellow, orange, and red areas overlaid in spots mainly toward the front.]]
[[File:An infographic explaining lead poisoning.jpg|thumb|An infographic explaining lead poisoning]]
{{see also|Lead–crime hypothesis}}
Lead affects the [[peripheral nervous system]] (especially [[motor nerve]]s) and the [[central nervous system]].<ref name="Dart041426"/> Peripheral nervous system effects are more prominent in adults, and central nervous system effects are more prominent in children.<ref name="Bellinger04-Pedi"/> Lead causes the [[axon]]s of [[neuron|nerve cells]] to degenerate and lose their [[myelin]] coats.<ref name="Dart041426"/>

<!-- COGNITIVE PERFORMANCE IN CHILDREN -->Lead exposure in young children has been linked to [[learning disability|learning disabilities]],<ref name="Meyer-IntJHyge"/> and children with blood lead concentrations greater than 10&nbsp;μg/dL are in danger of [[developmental disability|developmental disabilities]].<ref name="Brunton07-31"/> Increased blood lead level in children has been correlated with decreases in [[intelligence quotient|intelligence]], nonverbal reasoning, [[short-term memory]], attention, reading and arithmetic ability, [[fine motor skill]]s, [[emotional regulation]], and [[Social skill|social engagement]].<ref name="Cleveland08"/>

<!-- LOW LEVELS -->
The effect of lead on children's cognitive abilities takes place at very low levels.<ref name="Lanphear05EnvironHealth"/><ref name="Cleveland08"/><ref name="Bellinger08"/> There is no apparent lower threshold to the [[dose-response relationship]] (unlike other heavy metals such as [[mercury (element)|mercury]]).<ref>{{cite journal | vauthors = Needleman HL, Schell A, Bellinger D, Leviton A, Allred EN | title = The long-term effects of exposure to low doses of lead in childhood. An 11-year follow-up report | journal = The New England Journal of Medicine | volume = 322 | issue = 2 | pages = 83–8 | date = January 1990 | pmid = 2294437 | doi = 10.1056/NEJM199001113220203 | doi-access = free }}</ref> Reduced academic performance has been associated with lead exposure even at blood lead levels lower than 5&nbsp;μg/dL.<ref name="Merrill07861"/><ref name="Casarett07-944">[[#CITEREFCasarett07|Casarett, Klaassen, Doull (2007)]] p. 944</ref> Blood lead levels below 10&nbsp;μg/dL have been reported to be associated with lower IQ and behavior problems such as aggression, in proportion with blood lead levels.<ref name="Guidotti07-PedClin"/> Between the blood lead levels of 5 and 35&nbsp;μg/dL, an IQ decrease of 2–4 points for each μg/dL increase is reported in children.<ref name="Brunton07-31"/> However, studies that show associations between low-level lead exposure and health effects in children may be affected by [[confounding]] and overestimate the effects of low-level lead exposure.<ref>{{cite journal | vauthors = Wilson IH, Wilson SB | title = Confounding and causation in the epidemiology of lead | journal = International Journal of Environmental Health Research | volume = 26 | issue = 5–6 | pages = 467–82 | year = 2016 | pmid = 27009351 | doi = 10.1080/09603123.2016.1161179 | bibcode = 2016IJEHR..26..467W | s2cid = 39425465 }}</ref>

<!-- COGNITIVE PERFORMANCE IN ADULTS -->
High blood lead levels in adults are also associated with decreases in cognitive performance and with psychiatric symptoms such as depression and anxiety.<ref name="Shih07">{{cite journal | vauthors = Shih RA, Hu H, Weisskopf MG, Schwartz BS | title = Cumulative lead dose and cognitive function in adults: a review of studies that measured both blood lead and bone lead | journal = Environmental Health Perspectives | volume = 115 | issue = 3 | pages = 483–92 | date = March 2007 | pmid = 17431502 | pmc = 1849945 | doi = 10.1289/ehp.9786 | bibcode = 2007EnvHP.115..483S }}</ref> It was found in a large group of current and former inorganic lead workers in Korea that blood lead levels in the range of 20–50&nbsp;μg/dL were correlated with neuro-cognitive defects.<ref name="Kosnett07EnvironHealthPers"/> Increases in blood lead levels from about 50 to about 100&nbsp;μg/dL in adults are associated with persistent, and possibly permanent, impairment of central nervous system function.<ref name="Grant09-789"/>

<!-- BEHAVIOR -->
Lead exposure in children is also correlated with neuropsychiatric disorders such as [[attention deficit hyperactivity disorder]] and [[anti-social behaviour]].<ref name="Bellinger08">{{cite journal | vauthors = Bellinger DC | title = Very low lead exposures and children's neurodevelopment | journal = Current Opinion in Pediatrics | volume = 20 | issue = 2 | pages = 172–7 | date = April 2008 | pmid = 18332714 | doi = 10.1097/MOP.0b013e3282f4f97b | s2cid = 22985838 }}</ref> Elevated lead levels in children are correlated with higher scores on aggression and delinquency measures.<ref name="Need2004" /> A correlation has also been found between prenatal and early childhood lead exposure and violent crime in adulthood.<ref name="Cleveland08"/> Countries with the highest air lead levels have also been found to have the highest murder rates, after adjusting for confounding factors.<ref name="Need2004" /> A May 2000 study by economic consultant [[Rick Nevin]] theorizes that lead exposure explains 65% to 90% of the variation in violent crime rates in the US.<ref>{{cite web|url=http://www.icfi.com/Markets/Community_Development/doc_files/LeadExposureStudy.pdf |title=Research Links Lead Exposure to Changes in Violent Crime Rates Throughout the 20th century |publisher=ICF International |url-status=dead |archive-url=https://web.archive.org/web/20101230094829/http://www.icfi.com/Markets/Community_Development/doc_files/LeadExposureStudy.pdf |archive-date=2010-12-30 }}</ref><ref>{{cite journal | vauthors = Nevin R | title = How lead exposure relates to temporal changes in IQ, violent crime, and unwed pregnancy | journal = Environmental Research | volume = 83 | issue = 1 | pages = 1–22 | date = May 2000 | pmid = 10845777 | doi = 10.1006/enrs.1999.4045 | url = https://mpra.ub.uni-muenchen.de/35324/1/MPRA_paper_35324.pdf | bibcode = 2000ER.....83....1N | s2cid = 18983793 }}</ref> A 2007 paper by the same author claims to show a strong association between preschool blood lead and subsequent crime rate trends over several decades across nine countries.<ref>{{cite journal | vauthors = Nevin R | title = Understanding international crime trends: the legacy of preschool lead exposure | journal = Environmental Research | volume = 104 | issue = 3 | pages = 315–36 | date = July 2007 | pmid = 17451672 | doi = 10.1016/j.envres.2007.02.008 | url = https://mpra.ub.uni-muenchen.de/35338/1/MPRA_paper_35338.pdf | bibcode = 2007ER....104..315N }}</ref><ref name="Vedantam">{{cite news | first = Shankar | last = Vedantam |url=https://www.washingtonpost.com/wp-dyn/content/article/2007/07/07/AR2007070701073_pf.html |title=Research links lead exposure, criminal activity |newspaper=[[The Washington Post]] |date=July 8, 2007 |access-date=September 24, 2009 |url-status=live |archive-url=https://web.archive.org/web/20100920011559/http://www.washingtonpost.com/wp-dyn/content/article/2007/07/07/AR2007070701073_pf.html |archive-date=September 20, 2010 }}</ref> Lead exposure in childhood appears to increase school suspensions and juvenile detention among boys.<ref>{{cite journal |last1=Aizer |first1=Anna |last2=Currie |first2=Janet |date=May 2017 |title=Lead and Juvenile Delinquency: New Evidence from Linked Birth, School and Juvenile Detention Records |doi=10.3386/w23392 |journal=NBER Working Paper No. 23392 |url=http://www.nber.org/papers/w23392.pdf }}</ref> It is believed that the US ban on lead paint in buildings in the late 1970s, as well as the phaseout of leaded gasoline in the 1970s and 1980s, partially helped contribute to the decline of violent crime in the United States since the early 1990s.<ref name="Vedantam"/>

==Exposure routes==
{{Pollution sidebar|Solid waste}}

<!-- ENVIRONMENT -->
Lead is a common environmental pollutant.<ref name="Ragan09-JAAPA">{{cite journal | vauthors = Ragan P, Turner T | title = Working to prevent lead poisoning in children: getting the lead out | journal = JAAPA | volume = 22 | issue = 7 | pages = 40–5 | date = July 2009 | pmid = 19697571 | doi = 10.1097/01720610-200907000-00010 | s2cid = 41456653 }}</ref> Causes of environmental contamination include lead-based paint that is deteriorating (e.g. peeling, chipping, chalking, cracking, damp or damage), [[renovation]], repair or painting activities (disturbing or [[demolishing]] painted surfaces generate toxic lead dust 
),<ref>{{cite web | url=https://www.epa.gov/lead/protect-your-family-sources-lead | title=Protect Your Family from Sources of Lead| date=12 February 2013}}</ref> industrial use of lead, such as found in facilities that process [[lead-acid batteries]] or produce lead wire or pipes, [[metal recycling]] and [[foundries]],<ref name="Mañay08"/> 
and burning of [[joss paper]].<ref>{{cite web | url=https://www.researchgate.net/publication/233885602 | title=Parkinson s disease in occupational exposure to joss paper, a report of two cases}}</ref><ref>{{cite journal |title=Heavy metals emissions from joss paper burning rituals and the air quality around a specific incinerator|year=2021 |doi=10.1016/j.matpr.2020.08.686 |last1=Giang |first1=Lam Van |last2=Thanh |first2=Tran |last3=Hien |first3=Truong Thanh |last4=Tan |first4=Lam Van |last5=Thi Bich Phuong |first5=Tran |last6=Huu Loc |first6=Ho |journal=Materials Today: Proceedings |volume=38 |pages=2751–2757 |s2cid=226353498 |doi-access=free }}</ref><ref>{{cite web | url=
https://www.researchgate.net/publication/257494079 | title=Health risk of aerosols and toxic metals from incense and joss paper burning}}</ref> Storage batteries and ammunition are made with the largest amounts of lead consumed in the economy each year, in the US as of 2013.<ref name=Min2013>{{cite web |url=https://minerals.usgs.gov/minerals/pubs/commodity/lead/myb1-2013-lead.pdf |title=2013 Minerals Yearbook: LEAD|access-date=2017-02-21 }}</ref> Children living near facilities that process lead, such as [[lead smelter]]s, have been found to have unusually high blood lead levels.<ref name="Sanborn">{{cite journal | vauthors = Sanborn MD, Abelsohn A, Campbell M, Weir E | title = Identifying and managing adverse environmental health effects: 3. Lead exposure | journal = CMAJ | volume = 166 | issue = 10 | pages = 1287–92 | date = May 2002 | pmid = 12041847 | pmc = 111081 }}</ref> In August 2009, parents rioted in China after [[2009 Chinese lead poisoning scandal|lead poisoning was found in nearly 2000 children]] living near zinc and manganese smelters.<ref name="Watts09-Lancet">{{cite journal | vauthors = Watts J | title = Lead poisoning cases spark riots in China | journal = Lancet | volume = 374 | issue = 9693 | page = 868 | date = September 2009 | pmid = 19757511 | doi = 10.1016/S0140-6736(09)61612-3 | s2cid = 28603179 }}</ref> Lead exposure can occur from contact with lead in air, household dust, soil, water, and commercial products.<ref name="Rossi09"/> Leaded [[gasoline]] has also been linked to increases in lead pollution.<ref>{{cite web| url=http://www2.epa.gov/aboutepa/lead-poisoning-historical-perspective| first = Jack | last = Lewis | title=Lead Poisoning: A Historical Perspective| publisher=EPA| date=May 1985| url-status=dead| archive-url=https://web.archive.org/web/20160208011715/http://www.epa.gov/aboutepa/lead-poisoning-historical-perspective| archive-date=2016-02-08}}</ref><ref>{{cite magazine| url=https://www.wired.com/2013/01/looney-gas-and-lead-poisoning-a-short-sad-history/| first = Deborah | last = Blum | title=Looney Gas and Lead Poisoning: A Short, Sad History| magazine=Wired| date=January 5, 2013| url-status=live| archive-url=https://web.archive.org/web/20170321225320/https://www.wired.com/2013/01/looney-gas-and-lead-poisoning-a-short-sad-history/| archive-date=March 21, 2017}}</ref> Some research has suggested a link between leaded gasoline and crime rates.<ref>{{cite magazine| url=https://www.motherjones.com/environment/2013/01/lead-crime-link-gasoline| first = Kevin | last = Drum | title=America's Real Criminal Element: Lead| magazine=Mother Jones| date=January 2013| url-status=live| archive-url=https://web.archive.org/web/20140512040918/https://www.motherjones.com/environment/2013/01/lead-crime-link-gasoline| archive-date=2014-05-12}}</ref><ref>{{cite news| url=https://www.bbc.com/news/magazine-27067615| first = Dominic | last = Casciani | title=Did removing lead from petrol spark a decline in crime?| publisher=BBC| date=April 20, 2014| url-status=live| archive-url=https://web.archive.org/web/20170124183836/http://www.bbc.com/news/magazine-27067615| archive-date=January 24, 2017}}</ref> Man-made lead pollution has been elevated in the air for the past 2000 years.<ref>{{cite journal | vauthors = More AF, Spaulding NE, Bohleber P, Handley MJ, Hoffmann H, Korotkikh EV, Kurbatov AV, Loveluck CP, Sneed SB, McCormick M, Mayewski PA | title = Next-generation ice core technology reveals true minimum natural levels of lead (Pb) in the atmosphere: Insights from the Black Death | journal = GeoHealth | volume = 1 | issue = 4 | pages = 211–219 | date = June 2017 | pmid = 32158988 | pmc = 7007106 | doi = 10.1002/2017GH000064 | bibcode = 2017GHeal...1..211M }}</ref><ref>{{cite magazine| url=http://www.smithsonianmag.com/smart-news/humans-polluted-air-much-earlier-previously-thought-180963528/|  first = Erin | last = Blakemore | title=Humans Polluted the Air Much Earlier than Previously Thought| magazine=Smithsonian Magazine| date=June 2, 2017}}</ref><ref>{{cite web| url=https://eos.org/scientific-press/human-activity-has-polluted-european-air-for-2000-years| author=American Geophysical Union| title=Human Activity Has Polluted European Air for 2000 Years| work=Eos| publisher=Eos Science News| date=May 31, 2017| url-status=live| archive-url=https://web.archive.org/web/20170627215417/https://eos.org/scientific-press/human-activity-has-polluted-european-air-for-2000-years| archive-date=June 27, 2017}}</ref> Lead pollution in the air is entirely due to human activity (mining and smelting, as well as in gasoline).

===Occupational exposure===
[[File:Recycling lead in a lead-acid battery recovery facility.jpg|right|thumb|alt=A man in a hard hat with a clear face plate leans over a conveyor belt with a metal instrument. He is in a factory setting with heavy machinery in the background.|[[Battery recycling]] workers are at risk for lead exposure.<ref name="Brodkin07-CMAJ">{{cite journal | vauthors = Brodkin E, Copes R, Mattman A, Kennedy J, Kling R, Yassi A | title = Lead and mercury exposures: interpretation and action | journal = CMAJ | volume = 176 | issue = 1 | pages = 59–63 | date = January 2007 | pmid = 17200393 | pmc = 1764574 | doi = 10.1503/cmaj.060790 }}</ref> This worker ladles molten lead into billets in a lead-acid battery recovery facility.]]

In adults, occupational exposure is the main cause of lead poisoning.<ref name="Need2004" /> People can be exposed when working in facilities that produce a variety of lead-containing products; these include [[radiation shield]]s, ammunition, certain surgical equipment, developing dental X-ray films prior to digital X-rays (each film packet had a lead liner to prevent the radiation from going through), fetal monitors, plumbing, circuit boards, jet engines, and ceramic glazes.<ref name="Patrick06"/>{{ums|date=December 2017}}<ref>{{cite web |last=Turns |first=Anna |title=Mapping Our 'Pollution Landscape' |url=https://www.resurgence.org/magazine/article5894-mapping-our-pollution-landscape.html |access-date=2022-04-04 |website=www.resurgence.org |language=en}}</ref> In addition, lead miners and smelters, plumbers and fitters, auto mechanics, glass manufacturers, construction workers, battery manufacturers and [[Battery recycling#Lead–acid batteries|recyclers]], [[firing range]] workers, and plastic manufacturers are at risk for lead exposure.<ref name="Sanborn"/> Other occupations that present lead exposure risks include [[welding]], manufacture of rubber, printing, [[zinc]] and [[copper]] smelting, processing of [[ore]], combustion of [[solid waste]], and production of paints and pigments.<ref name="Dart041424">[[#CITEREFDart04|Dart, Hurlbut, Boyer-Hassen (2004)]] p. 1424</ref> Lead exposure can also occur with intense use of [[gun range]]s, regardless of whether these ranges are indoor or out.<ref>{{cite journal | vauthors = Laidlaw MA, Filippelli G, Mielke H, Gulson B, Ball AS | title = Lead exposure at firing ranges-a review | journal = Environmental Health | volume = 16 | issue = 1 | page = 34 | date = April 2017 | pmid = 28376827 | pmc = 5379568 | doi = 10.1186/s12940-017-0246-0 | doi-access = free | bibcode = 2017EnvHe..16...34L }}</ref> Parents who are exposed to lead in the workplace can bring lead dust home on clothes or skin and expose their children.<ref name="Dart041424"/> Occupational exposure to lead increases the risk of [[cardiovascular disease]], in particular: [[stroke]], and [[high blood pressure]].<ref name="SBU2017">{{cite web|url=https://www.sbu.se/en/publications/sbu-assesses/occupational-health-and-safety--chemical-exposure/|title=Occupational health and safety – chemical exposure|publisher=[[Swedish Agency for Health Technology Assessment and Assessment of Social Services]] (SBU)|date=2017-03-28|website=www.sbu.se|access-date=2017-06-07|archive-url=https://web.archive.org/web/20170606093333/http://www.sbu.se/en/publications/sbu-assesses/occupational-health-and-safety--chemical-exposure/|archive-date=2017-06-06|url-status=dead}}</ref>

=== Food ===
Lead may be found in food when food is grown in soil that is high in lead, airborne lead contaminates the crops, animals eat lead in their diet, or lead enters the food either from what it was stored or cooked in.<ref>{{cite book |last1=Castellino |first1=Nicolo |last2=Sannolo |first2=Nicola |last3=Castellino |first3=Pietro |title=Inorganic Lead Exposure and Intoxications|date=1994|publisher=CRC Press|isbn=978-0-87371-997-1|page=86|url=https://books.google.com/books?id=059oObc8X48C&pg=PA86|url-status=live|archive-url=https://web.archive.org/web/20171105194927/https://books.google.com/books?id=059oObc8X48C&pg=PA86|archive-date=2017-11-05}}</ref> Ingestion of lead paint and batteries is also a route of exposure for livestock, which can subsequently affect humans.<ref>{{cite journal |last1=Hesami |first1=Reza |last2=Salimi |first2=Azam |last3=Ghaderian |first3=Seyed Majid |date=2018-01-10 |title=Lead, zinc, and cadmium uptake, accumulation, and phytoremediation by plants growing around Tang-e Douzan lead–zinc mine, Iran |url=http://dx.doi.org/10.1007/s11356-017-1156-y |journal=Environmental Science and Pollution Research |volume=25 |issue=9 |pages=8701–8714 |doi=10.1007/s11356-017-1156-y |pmid=29322395 |bibcode=2018ESPR...25.8701H |s2cid=3938066 |issn=0944-1344|url-access=subscription }}</ref> Milk produced by contaminated cattle can be diluted to a lower lead concentration and sold for consumption.<ref>{{cite journal |last1=Mielke |first1=Howard W. |last2=Reagan |first2=Patrick L. |date=February 1998 |title=Soil Is an Important Pathway of Human Lead Exposure |url=http://dx.doi.org/10.2307/3433922 |journal=Environmental Health Perspectives |volume=106 |issue=Suppl 1 |pages=217–229 |doi=10.2307/3433922 |jstor=3433922 |pmid=9539015 |pmc=1533263 |issn=0091-6765}}</ref>

In Bangladesh, [[lead chromate]] has been added to [[turmeric]] to make it more yellow.<ref name=Stan2019>{{cite news |last1=University |first1=Stanford |title=Lead found in turmeric |url=https://news.stanford.edu/2019/09/24/lead-found-turmeric/ |access-date=25 September 2019 |work=Stanford News |date=24 September 2019}}</ref> This is believed to have started in the 1980s.<ref name=Stan2019/> It was believed to have been one of the main sources of high lead levels in the country.<ref>{{cite news |title=Researchers find lead in turmeric |url=https://phys.org/news/2019-09-turmeric.html |access-date=25 September 2019 |work=phys.org}}</ref> Following a 2019 report identifying adulterated turmeric as the main cause of lead poisoning in Bangladesh, the government began a rapid crackdown and public service campaign on it. By 2021, leaded turmeric had vanished from the Bangladeshi market, and blood lead levels in workers at turmeric mills had dropped by a median of 30%.<ref>{{cite news |last1=Piper |first1=Kelsey |title=Lead poisoning kills millions annually. One country is showing the way forward. |url=https://www.vox.com/future-perfect/2023/9/20/23881981/bangladesh-tumeric-lead-poisoning-contamination-public-health |work=Vox |date=20 September 2023 |language=en}}</ref><ref>{{cite journal |last1=Forsyth |first1=Jenna E. |last2=Baker |first2=Musa |last3=Nurunnahar |first3=Syeda |last4=Islam |first4=Shariful |last5=Islam |first5=M. Saiful |last6=Islam |first6=Tauhidul |last7=Plambeck |first7=Erica |last8=Winch |first8=Peter J. |last9=Mistree |first9=Dinsha |last10=Luby |first10=Stephen P. |last11=Rahman |first11=Mahbubur |title=Food safety policy enforcement and associated actions reduce lead chromate adulteration in turmeric across Bangladesh |journal=Environmental Research |date=1 September 2023 |volume=232 |pages=116328 |doi=10.1016/j.envres.2023.116328 |pmid=37286126 |bibcode= 2023ER....23216328F|issn=0013-9351|doi-access=free }}</ref>

In Hong Kong, the maximum allowed lead parts per million is 6 in solid foods and 1 in liquid foods.<ref>{{cite web |title=Maximum Permitted Concentration of Certain Metals Present in Specified Foods |url=https://www.elegislation.gov.hk/hk/cap132V!en@2019-09-19T00:00:00?INDEX_CS=N&xpid=ID_1438402695833_003 |website=www.elegislation.gov.hk |access-date=15 April 2020}}</ref>

In December 2022, 28 [[dark chocolate]] brands were tested by [[Consumer Reports]], which found that 23 of them contained [[cadmium]], lead or both.<ref>{{cite web |title=Consumer Reports urges dark chocolate makers to reduce lead, cadmium levels |url=https://www.yahoo.com/lifestyle/consumer-reports-urges-dark-chocolate-155747068.html |access-date=2023-01-28 |website=www.yahoo.com |date=23 January 2023 |language=en-US}}</ref> When cocoa beans are set outside near polluting industrial plants, they can be contaminated by dust containing lead.<ref>[https://www.wbur.org/hereandnow/2023/02/01/dark-chocolate-lead-cadmium Dark chocolate is high in cadmium and lead. How much is safe to eat?]</ref>

===Paint===
Some lead compounds are colorful and are used widely in paints,<ref name="Henretig06">[[#CITEREFHenretig06|Henretig (2006)]] p. 1310</ref><ref>{{cite web|date=2021-07-13|title=Study results: Malawi and Botswana|url=https://leadelimination.org/study-results-malawi-and-botswana/|access-date=2021-12-01|website=Lead Elimination|language=en-GB}}</ref> and lead paint is a major route of lead exposure in children.<ref name="Gilbert06">{{cite journal | vauthors = Gilbert SG, Weiss B | title = A rationale for lowering the blood lead action level from 10 to 2 microg/dL | journal = Neurotoxicology | volume = 27 | issue = 5 | pages = 693–701 | date = September 2006 | pmid = 16889836 | pmc = 2212280 | doi = 10.1016/j.neuro.2006.06.008 }}</ref> A study conducted in 1998–2000 found that 38 million housing units in the US had lead-based paint, down from a 1990 estimate of 64 million.<ref name="autogenerated1">{{cite journal | vauthors = Jacobs DE, Clickner RP, Zhou JY, Viet SM, Marker DA, Rogers JW, Zeldin DC, Broene P, Friedman W | title = The prevalence of lead-based paint hazards in U.S. housing | journal = Environmental Health Perspectives | volume = 110 | issue = 10 | pages = A599-606 | date = October 2002 | pmid = 12361941 | pmc = 1241046 | doi = 10.1289/ehp.021100599 | jstor = 3455813 }}</ref> Deteriorating lead paint can produce dangerous lead levels in household dust and soil.<ref name="Dart041423">[[#CITEREFDart04|Dart, Hurlbut, Boyer-Hassen (2004)]] p. 1423</ref> Deteriorating lead paint and lead-containing household dust are the main causes of chronic lead poisoning.<ref name="Pearce07-EurNeurol"/> The lead breaks down into the dust, and since children are more prone to crawling on the floor, it is easily ingested.<ref name="autogenerated1"/> Many young children display [[Pica (disorder)|pica]], eating things that are not food. Even a small amount of a lead-containing product, such as a paint chip or a sip of glaze, can contain tens or hundreds of milligrams of lead.<ref name="Kosnett06-241"/> Eating chips of lead paint presents a particular hazard to children, generally producing more severe poisoning than lead-contaminated dust.<ref name="Chisolm04-222"/> Because removing lead paint from dwellings, e.g. by sanding or torching, creates lead-containing dust and fumes, it is generally safer to seal the lead paint under new paint (excepting moveable windows and doors, which create paint dust when operated).<ref name="Salvato03"/> Alternatively, special precautions must be taken if the lead paint is to be removed.<ref name="Salvato03">[[#CITEREFSalvato03|Salvato (2003)]] p. 116</ref>

In [[oil painting]], it was once common for colours such as yellow or white to be made with lead carbonate. [[Lead paint#Oil paints|Lead white]] oil colour was the main white of oil painters until superseded by compounds containing [[Zinc oxide#Pigment|zinc]] or [[Titanium dioxide#Pigment|titanium]] in the mid-20th century. It is speculated that the painter [[Caravaggio]] and possibly [[Francisco Goya]] and [[Vincent van Gogh's health|Vincent Van Gogh]] had lead poisoning due to overexposure or carelessness when handling this colour.<ref>{{cite news|url=https://www.theguardian.com/artanddesign/2010/jun/16/caravaggio-italy-remains-ravenna-art|title=The mystery of Caravaggio's death solved at last – painting killed him| first = Tom | last = Kington |newspaper=The Guardian|url-status=live|archive-url=https://web.archive.org/web/20130825140508/http://www.theguardian.com/artanddesign/2010/jun/16/caravaggio-italy-remains-ravenna-art|archive-date=2013-08-25|date=2010-06-16}}</ref>

===Soil===
[[File:Gas pump lead warning.jpg|thumb|right|A lead warning on a fuel pump. [[Tetraethyllead]], which used to be added to automotive gasoline (and still is added to some [[avgas|aviation gasolines]]), contributed to [[soil contamination]].|alt=a closeup of a red gasoline pump with a warning label that reads, "for use as a motor fuel only" (in larger writing) "contains lead" (in smaller writing) "(tetraethyl)"]]
Residual lead in soil contributes to lead exposure in urban areas.<ref name="Guidotti07-PedClin"/> It has been thought that the more polluted an area is with various contaminants, the more likely it is to contain lead. However, this is not always the case, as there are several other reasons for lead contamination in soil.<ref>{{cite journal | vauthors = Barltrop D, Strehlow CD, Thornton I, Webb JS | title = Absorption of lead from dust and soil | journal = Postgraduate Medical Journal | volume = 51 | issue = 601 | pages = 801–4 | date = November 1975 | pmid = 1208289 | pmc = 2496115 | doi = 10.1136/pgmj.51.601.801 }}</ref>

Lead content in soil may be caused by broken-down lead paint, residues from lead-containing gasoline, used engine oil, [[tire balance#Environmental consequences|tire weights]], or [[pesticide]]s used in the past, [[contaminated land]]fills, or from nearby industries such as [[foundry|foundries]] or smelters.<ref name="Woolf07-PedClin" /> For example, in the [[Montevideo]] neighborhood of [[La Teja]], former industrial sites became important sources of exposure in local communities in the early 2000s.<ref>{{cite web|date=2020-02-28|title=Living with lead in Uruguay|url=https://toxicnews.org/2020/02/28/living-with-lead-in-uruguay/|access-date=2022-01-26|website=Toxic News|language=en}}</ref> Although leaded soil is less of a problem in countries that no longer have [[gasoline#Lead|leaded gasoline]], it remains prevalent, raising concerns about the safety of [[urban agriculture]];<ref>{{cite news | vauthors = Murphy K |date=May 13, 2009 |url=https://www.nytimes.com/2009/05/14/garden/14lead.html |title=For urban gardeners, lead is a concern |work=[[The New York Times]] |access-date=September 18, 2009 |url-status=live |archive-url=https://web.archive.org/web/20140503034153/http://www.nytimes.com/2009/05/14/garden/14lead.html |archive-date=May 3, 2014 }}</ref> eating food grown in contaminated soil can present a lead hazard.<ref name="Yu05-188">[[#CITEREFYu05|Yu (2005)]] p. 188</ref> Interfacial solar evaporation has been recently studied as a technique for remediating lead-contaminated sites, which involves the evaporation of heavy metal ions from moist soil.<ref>{{cite journal |last1=Wu |first1=Pan |last2=Wu |first2=Xuan |last3=Xu |first3=Haolan |last4=Owens |first4=Gary |date=2021-09-05 |title=Interfacial solar evaporation driven lead removal from a contaminated soil |journal=EcoMat |volume=3 |issue=5 |doi=10.1002/eom2.12140 |s2cid=239680091 |issn=2567-3173|doi-access=free |hdl=11541.2/29296 |hdl-access=free }}</ref>

[[File:Lead wheel weight and dust.jpg|thumb|Lead wheel weight eroding on road]]

===Water===
Lead from the atmosphere or soil can end up in groundwater and surface water.<ref name="Yu05">[[#CITEREFYu05|Yu (2005)]] p. 187</ref> It is also potentially in [[drinking water]], e.g. from plumbing and fixtures that are either made of lead or have <!--to avoid 'have led/lead' search-->lead solder.<ref name="Chisolm04-222">[[#CITEREFChisolm04|Chisolm (2004)]] pp. 221–22</ref><ref name="Menkes06-703">[[#CITEREFMenkes06|Menkes (2006)]] p. 703</ref> Since acidic water breaks down lead in plumbing more readily, chemicals can be added to municipal water to increase the [[pH]] and thus reduce the [[Corrosion|corrosivity]] of the public [[water supply]].<ref name="Chisolm04-222"/> [[monochloramine|Chloramine]]s, which were adopted as a substitute for [[chlorine]] [[disinfectant]]s due to fewer health concerns, increase corrosivity.<ref name="Maas2005" /> In the US, 14–20% of total lead exposure is attributed to [[drinking water]].<ref name="Maas2005">{{cite journal | vauthors = Maas RP, Patch SC, Morgan DM, Pandolfo TJ | title = Reducing lead exposure from drinking water: recent history and current status | journal = Public Health Reports | volume = 120 | issue = 3 | pages = 316–21 | year = 2005 | pmid = 16134575 | pmc = 1497727 | doi = 10.1177/003335490512000317 }}</ref> In 2004, a team of seven reporters from ''[[The Washington Post]]'' discovered [[Lead contamination in Washington, D.C. drinking water|high levels of lead in the drinking water in Washington, DC]], and won an award for [[investigative reporting]] for a series of articles about this contamination.<ref>{{cite web |title=Alum Wins Investigative Reporting Award with Post Team |publisher=[[University of Maryland College Park|University of Maryland]] |date=February 25, 2005 |url=http://www.journalism.umd.edu/newrel/05newrel/scohen05.html |access-date=2007-11-07 |archive-url = https://web.archive.org/web/20060912005549/http://www.journalism.umd.edu/newrel/05newrel/scohen05.html |archive-date = September 12, 2006}}</ref><ref>{{cite news |title=HONORS |newspaper=The Washington Post|date=February 23, 2005 }}</ref> In the [[Flint water crisis|water crisis in Flint, Michigan]], a switch to a more corrosive municipal water source caused elevated lead levels in domestic tap water.<ref>{{cite news|url=https://www.washingtonpost.com/news/wonk/wp/2016/01/15/this-is-how-toxic-flints-water-really-is/|title=This is how toxic Flint's water really is| first = Christopher | last = Ingraham |date=15 January 2016|newspaper=[[The Washington Post]]}}</ref><ref>{{cite web | first =  Eliott C. | last = McLaughlin | url = https://edition.cnn.com/2016/01/18/us/flint-michigan-water-crisis-five-things/index.html |title=Flint's water crisis: 5 things to know | date=18 January 2016 |url-status=live |archive-url= https://web.archive.org/web/20160123081451/http://edition.cnn.com/2016/01/18/us/flint-michigan-water-crisis-five-things/index.html |archive-date=23 January 2016| work = CNN }}</ref>

Like Flint, Michigan, and Washington, D.C., a similar situation affects the state of Wisconsin, where estimates call for replacement of up to 176,000 underground pipes made of lead known as [[lead service line]]s. The City of [[Madison, Wisconsin]] addressed the issue and replaced all of their lead service lines, but there are still other cities that have yet to follow suit. While there are chemical methods that could help reduce the amount of lead in the water distributed, a permanent fix would be to replace the pipes completely. While the state may replace the pipes below ground, homeowners must replace the pipes on their property, at an average cost of $3,000.<ref name="wpr.org">{{cite web | first = Shawn | last = Johnson | work = Wisconsin Public Radio | url=https://www.wpr.org/wisconsin-senate-unanimously-passes-bill-remove-lead-water-pipes | title=Wisconsin Senate Unanimously Passes Bill to Remove Lead Water Pipes| date=2017-10-30}}</ref> Experts say that if the city were to replace their pipes and the citizens were to keep the old pipes located within their homes, there would be a potential for more lead to dissolve into their drinking water.<ref name="wpr.org"/> The US Congress authorized the EPA to dedicate funds to assist states and nonprofits with the costs of lead service line removal under Section 50105 of the [[Safe Drinking Water Act]].<ref>{{cite web |last1=Humphreys |first1=Elena, H. |last2=Ramseur |first2=Jonathan |date=2022-01-04 |title=Infrastructure Investment and Jobs Act (IIJA): Drinking Water and Wastewater Infrastructure |url=https://crsreports.congress.gov/product/pdf/R/R46892 |access-date=2023-01-15 |website=Congressional Research Service |publisher=[[Library of Congress]]}}</ref> 
 
Collected rainwater from roof runoff used as potable water may contain lead if there are lead contaminants on the roof or in the storage tank.<ref name="Rossi09"/> The Australian Drinking Water Guidelines allow a maximum of 0.01&nbsp;mg/L (10&nbsp;ppb) lead in water.<ref name="Rossi09">{{cite journal | vauthors = Rossi E | title = Low level environmental lead exposure--a continuing challenge | journal = The Clinical Biochemist. Reviews | volume = 29 | issue = 2 | pages = 63–70 | date = May 2008 | pmid = 18787644 | pmc = 2533151 }}</ref>

Lead wheel weights have been found to accumulate on roads and interstates and erode in traffic, entering the water runoff through drains. Leaded fishing weights accumulate in rivers, streams, ponds, and lakes.

=== Gasoline ===
[[Tetraethyllead]] was first added to gasoline in 1923, as it helped prevent [[engine knocking]]. Automotive exhaust represented a major way for lead to be inhaled, invade the bloodstream, and pass into the brain.<ref>[https://today.duke.edu/2022/03/lead-exposure-last-century-shrunk-iq-scores-half-americans Lead Exposure in Last Century Shrank IQ Scores of Half of Americans]</ref>

The use of lead in gasoline peaked in the 1970s. By the next decade, most high-income countries prohibited the use of leaded petrol. As late as 2002, almost all low- and middle-income countries, including some [[OECD]] members, still used it. The [[UN Environment Programme]] (UNEP) thus launched a campaign in 2002 to eliminate its use, leading to Algeria being the last country to stop its use in July 2021.<ref>[https://www.unep.org/news-and-stories/press-release/era-leaded-petrol-over-eliminating-major-threat-human-and-planetary Era of leaded petrol over, eliminating a major threat to human and planetary health]</ref>

===Lead-containing products===
Lead can be found in products such as [[kohl (cosmetics)|kohl]], an ancient cosmetic from the Middle East, South Asia, and parts of Africa that has many other names, and in some toys.<ref name="Guidotti07-PedClin"/> [[2007 Chinese export recalls|In 2007, millions of toys made in China were recalled]] from multiple countries owing to safety hazards, including lead paint.<ref>{{cite news|url=http://www.cnn.com/2007/US/08/14/recall/index.html|title=Mattel CEO: 'Rigorous standards' after massive toy recall|publisher=CNN|date=November 15, 2007|access-date=September 26, 2009|url-status=live|archive-url=https://web.archive.org/web/20090825115546/http://www.cnn.com/2007/US/08/14/recall/index.html|archive-date=August 25, 2009}}</ref> Vinyl mini-blinds, found especially in older housing, may contain lead.<ref name="Ragan09-JAAPA"/><!--
MEDICINE-->
Lead is commonly incorporated into [[herbalism|herbal remedies]] such as Indian [[Ayurveda|Ayurvedic]] preparations and remedies of Chinese origin.<ref name="Rossi09"/><ref name="Karri08"/> There are also risks of elevated blood lead levels caused by folk remedies like {{Lang|es|azarcon}} and {{Lang|es|greta}}, powders containing lead tetroxide and lead oxide, respectively, which each contain about 95% lead.<ref name="Karri08"/><ref>{{cite journal |date=October 28, 1983 |title=Lead Poisoning from Mexican Folk Remedies – California |url=https://www.cdc.gov/mmwr/preview/mmwrhtml/00000164.htm |journal=[[Morbidity and Mortality Weekly Report]] |volume=32 |issue=42}}</ref>

<!--FOOD -->
Ingestion of metallic lead, such as small lead fishing lures, increases blood lead levels and can be fatal.<ref>{{cite journal | vauthors = Schep LJ, Fountain JS, Cox WM, Pesola GR | title = Lead shot in the appendix | journal = The New England Journal of Medicine | volume = 354 | issue = 16 | pages = 1757; author reply 1757 | date = April 2006 | pmid = 16625019 | doi = 10.1056/NEJMc060133 }}</ref><ref>{{cite journal | vauthors = Madsen HH, Skjødt T, Jørgensen PJ, Grandjean P | title = Blood lead levels in patients with lead shot retained in the appendix | journal = Acta Radiologica | volume = 29 | issue = 6 | pages = 745–6 | year = 1988 | pmid = 3190952 | doi = 10.1080/02841858809171977 }}</ref><ref>{{cite journal | vauthors = Durlach V, Lisovoski F, Gross A, Ostermann G, Leutenegger M | title = Appendicectomy in an unusual case of lead poisoning | journal = Lancet | volume = 1 | issue = 8482 | pages = 687–8 | date = March 1986 | pmid = 2869380 | doi = 10.1016/S0140-6736(86)91769-1 | s2cid = 1834967 }}</ref><ref>{{cite journal | title = Death of a child after ingestion of a metallic charm--Minnesota, 2006 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 55 | issue = 12 | pages = 340–1 | date = March 2006 | pmid = 16572103 | author1 = Centers for Disease Control Prevention (CDC) }}</ref> Ingestion of lead-contaminated food is also a threat. Ceramic glaze often contains lead, and dishes that have been improperly fired can leach the metal into food, potentially causing severe poisoning.<ref name="Salvato03-117"/> In some places, the solder in cans used for food contains lead.<ref name="Patrick06"/> People who eat animals hunted with lead bullets may be at risk for lead exposure.<ref name="ReferenceA">{{cite journal | vauthors = Hunt WG, Watson RT, Oaks JL, Parish CN, Burnham KK, Tucker RL, Belthoff JR, Hart G | title = Lead bullet fragments in venison from rifle-killed deer: potential for human dietary exposure | journal = PLOS ONE | volume = 4 | issue = 4 | page = e5330 | year = 2009 | pmid = 19390698 | pmc = 2669501 | doi = 10.1371/journal.pone.0005330 | veditors = Zhang B | bibcode = 2009PLoSO...4.5330H | doi-access = free }}</ref> Bullets lodged in the human body rarely cause significant levels of lead,<ref name="Spitz08-ArqNeruo">{{cite journal | vauthors = Spitz M, Lucato LT, Haddad MS, Barbosa ER | title = Choreoathetosis secondary to lead toxicity | journal = Arquivos de Neuro-Psiquiatria | volume = 66 | issue = 3A | pages = 575–7 | date = September 2008 | pmid = 18813727 | doi = 10.1590/S0004-282X2008000400031 | doi-access = free }}</ref><ref>{{cite journal | vauthors = DiMaio VJ, DiMaio SM, Garriott JC, Simpson P | title = A fatal case of lead poisoning due to a retained bullet | journal = The American Journal of Forensic Medicine and Pathology | volume = 4 | issue = 2 | pages = 165–9 | date = June 1983 | pmid = 6859004 | doi = 10.1097/00000433-198306000-00013 }}</ref> but bullets lodged in the joints are the exception, as they deteriorate and release lead into the body over time.<ref>{{cite journal | vauthors = Fiorica V, Brinker JE | title = Increased lead absorption and lead poisoning from a retained bullet | journal = The Journal of the Oklahoma State Medical Association | volume = 82 | issue = 2 | pages = 63–7 | date = February 1989 | pmid = 2926538 }}</ref>

In May 2015, Indian food safety regulators in the state of Uttar Pradesh found that samples of [[Maggi]] 2 Minute Noodles [[Maggi noodles safety concerns in India|contained lead]] up to 17 times beyond permissible limits.<ref>{{cite web | author = Merofact Awareness Team  |url=http://merofact.blogspot.in/2015/05/doubts-over-msg-and-lead-content-in.html|title=Doubts over MSG and Lead Content in Maggi Instant Noodles |date=19 May 2015 |url-status=live |archive-url= https://web.archive.org/web/20160114004630/http://merofact.blogspot.in/2015/05/doubts-over-msg-and-lead-content-in.html |archive-date=14 January 2016 }}</ref><ref>{{cite news|title=Beware! Eating 2 -Minute Maggi Noodles can ruin your Nervous System|url=http://news.biharprabha.com/2015/05/beware-eating-2-minute-maggi-noodles-can-ruin-your-nervous-system/|access-date=18 May 2015|publisher=news.biharprabha.com|date=18 May 2015|url-status=live|archive-url=https://web.archive.org/web/20150521005237/http://news.biharprabha.com/2015/05/beware-eating-2-minute-maggi-noodles-can-ruin-your-nervous-system/|archive-date=21 May 2015}}</ref><ref>{{cite news|url=http://m.ndtv.com/india-news/maggi-noodles-packets-recalled-across-uttar-pradesh-say-food-inspectors-764729|work=[[NDTV]]|title=Maggi Noodles Packets Recalled Across Uttar Pradesh, Say Food Inspectors: Report|date=20 May 2015|access-date=20 May 2015|location=[[New Delhi]], India|url-status=live|archive-url=https://web.archive.org/web/20150525204803/http://m.ndtv.com/india-news/maggi-noodles-packets-recalled-across-uttar-pradesh-say-food-inspectors-764729|archive-date=25 May 2015}}</ref><ref>{{cite news|first = Sushmi | last = Dey |url=https://timesofindia.indiatimes.com/india/Maggi-under-regulatory-scanner-for-lead-MSG-beyond-permissible-limit/articleshow/47304615.cms|work=[[The Times of India]]|title='Maggi' under regulatory scanner for lead, MSG beyond permissible limit|date=16 May 2015|access-date=20 May 2015|location=[[New Delhi]], India|url-status=live|archive-url=https://web.archive.org/web/20150526230502/http://timesofindia.indiatimes.com/india/Maggi-under-regulatory-scanner-for-lead-MSG-beyond-permissible-limit/articleshow/47304615.cms|archive-date=26 May 2015}}</ref> On 3 June 2015, the [[New Delhi]] Government banned the sale of Maggi noodles in New Delhi stores for 15 days because it was found to contain lead beyond the permissible limit.<ref>{{cite news | first = Durgesh Nandan | last = Jha |url=http://timesofindia.indiatimes.com/india/Delhi-govt-bans-sales-of-Maggi-from-its-stores/articleshow/47525207.cms|work=[[Times of India]]|title=Delhi govt bans sales of Maggi from its stores: Report|date=3 June 2015|access-date=3 June 2015|location=[[New Delhi]], India|url-status=live|archive-url=https://web.archive.org/web/20151016215428/http://timesofindia.indiatimes.com/india/Delhi-govt-bans-sales-of-Maggi-from-its-stores/articleshow/47525207.cms|archive-date=16 October 2015}}</ref> The [[Gujarat]] FDA on 4 June 2015 banned the noodles for 30 days after 27 out of 39 samples were detected with objectionable levels of metallic lead, among other things.<ref>{{cite web|url=http://timesofindia.indiatimes.com/india/Gujarat-bans-Maggi-noodles-for-30-days/articleshow/47541846.cms|archive-url=https://web.archive.org/web/20150607080312/http://timesofindia.indiatimes.com/india/Gujarat-bans-Maggi-noodles-for-30-days/articleshow/47541846.cms|url-status=dead|archive-date=2015-06-07|title=Gujarat bans Maggi noodles for 30 days|author=IANS|work=[[The Times of India]]|publisher=([[The Times Group]])|date=June 4, 2015|access-date=June 4, 2015}}</ref> Some of India's biggest retailers like [[Future Group]], [[Big Bazaar]], [[Easyday]], and Nilgiris have imposed a nationwide ban on Maggi noodles.<ref>{{cite news | first = Sunainaa | last = Chadha |url=http://www.firstpost.com/business/future-group-bans-maggi-too-the-two-minute-death-of-a-indias-favourite-noodle-brand-2277008.html|work=[[FirstPost]]|title=Future Group bans Maggi too: The two-minute death of an India's favourite noodle brand|date=3 June 2015|access-date=3 June 2015|url-status=live|archive-url=https://web.archive.org/web/20150604111756/http://www.firstpost.com/business/future-group-bans-maggi-too-the-two-minute-death-of-a-indias-favourite-noodle-brand-2277008.html|archive-date=4 June 2015}}</ref> Many other states too have banned Maggi noodles.

===Bullets===
Contact with ammunition is a source of lead exposure. As of 2013, lead-based ammunition production is the second largest annual use of lead in the US, accounting for over 84,800 metric tons in 2013,<ref name=Min2013/> second only to the manufacture of storage batteries.<ref name=Min2013/><ref>{{cite web |url=http://minerals.usgs.gov/minerals/pubs/commodity/lead/mis-201412-lead.pdf |title=Lead Statistics and Information | work = Mineral Industry Surveys | publisher = U.S. Department of the Interior |access-date=2016-07-11 |url-status=live |archive-url=https://web.archive.org/web/20160310030035/http://minerals.usgs.gov/minerals/pubs/commodity/lead/mis-201412-lead.pdf |archive-date=2016-03-10 }}</ref> The Environmental Protection Agency (EPA) cannot regulate cartridges and shells, as a matter of law.<ref>{{cite web | url = https://www.cadc.uscourts.gov/internet/opinions.nsf/0/421BCEB1FE2C191285257DB70054D62E/$file/13-5228-1528839.pdf | title = Trumpeter Swan Society vs EPA | work = United States Court of Appeals for the District of Columbia Circuit | archive-url = https://web.archive.org/web/20160506054634/https://www.cadc.uscourts.gov/internet/opinions.nsf/0/421BCEB1FE2C191285257DB70054D62E/$file/13-5228-1528839.pdf | archive-date=2016-05-06 }}</ref> Lead [[birdshot]] is banned in some areas, but this is primarily for the benefit of the birds and their predators, rather than humans.<ref name="lead-ban">{{cite web|title=Lead Exposure in Wisconsin Birds|publisher=Wisconsin Department of Natural Resources |date=3 September 2008|url=http://dnr.wi.gov/topic/hunt/documents/pbbirds.pdf|access-date=10 December 2012|url-status=live|archive-url=https://web.archive.org/web/20130728222536/http://dnr.wi.gov/topic/hunt/documents/pbbirds.pdf|archive-date=28 July 2013}}</ref> Contamination from heavily used gun ranges is of concern to those who live near by.<ref>{{cite news|last1=Wheeling|first1=Kate |title=An Environmental Case for Biodegradable Bullets|url=https://psmag.com/magazine/a-case-for-biodegradable-bullets|access-date=9 February 2018|work=[[Pacific Standard]]|date=8 February 2018}}</ref> Non-lead alternatives include [[copper]], [[zinc]], [[steel]], [[tungsten]]-[[nickel]]-[[iron]], [[bismuth]]-[[tin]], and polymer blends such as tungsten-polymer and copper-polymer.

Because game animals can be shot using lead bullets, the potential for lead ingestion from game meat consumption has been studied clinically and epidemiologically. In a recent study conducted by the CDC,<ref name=Iqbal2009>{{cite journal | vauthors = Iqbal S, Blumenthal W, Kennedy C, Yip FY, Pickard S, Flanders WD, Loringer K, Kruger K, Caldwell KL, Jean Brown M | title = Hunting with lead: association between blood lead levels and wild game consumption | journal = Environmental Research | volume = 109 | issue = 8 | pages = 952–9 | date = November 2009 | pmid = 19747676 | doi = 10.1016/j.envres.2009.08.007 | bibcode = 2009ER....109..952I }}</ref> a cohort from North Dakota was enrolled and asked to self-report historical consumption of game meat, and participation in other activities that could cause lead exposure. The study found that participants' age, sex, housing age, current hobbies with potential for lead exposure, and game consumption were all associated with blood lead level (PbB).

According to a study published in 2008, 1.1% of the 736 persons consuming wild game meat tested had PbB ≥5&nbsp;μg/dL<ref name="Iqbal">{{cite web|last=Iqbal |first=Shahed |title=Epi-AID Trip Report: Assessment of human health risk from consumption of wild game meat with possible lead contamination among the residents of the State of North Dakota |url=http://www.rmef.org/NR/rdonlyres/F07627AA-4D94-4CBC-B8FD-4F4F18401303/0/ND_report.pdf |work=Epi-AID Trip Report |publisher=National Center for Environmental Health, Centers for Disease Control and Prevention: Atlanta, Georgia, USA. |access-date=March 2, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110526095843/http://www.rmef.org/NR/rdonlyres/F07627AA-4D94-4CBC-B8FD-4F4F18401303/0/ND_report.pdf |archive-date=May 26, 2011 }}</ref> In November 2015 the US Health and Human Services (HHS), Centers for Disease Control and Prevention (CDC), and National Institute for Occupational Safety and Health (NIOSH) designated 5&nbsp;μg/dL (five micrograms per deciliter) of whole blood, in a venous blood sample, as the reference blood lead level for adults. An elevated blood lead level (BLL) is defined as a BLL ≥5&nbsp;μg/dL. This case definition is used by the [[Adult Blood Lead Epidemiology and Surveillance]] (ABLES) program, the Council of State and Territorial Epidemiologists (CSTE), and the CDC's National Notifiable Diseases Surveillance System (NNDSS). Previously (i.e., from 2009 until November 2015), the case definition for an elevated BLL was a BLL ≥10&nbsp;μg/dL.<ref name="NIOSH2015"/>

[[File:45 Auto Rim comparison.jpg|thumb|Jacketed ammunition (left), bare lead (right)]]
 
To virtually eliminate the potential for lead contamination, some researchers have suggested the use of lead-free copper non-fragmenting bullets.<ref name="ReferenceA"/>

[[Bismuth]] is an element used as a lead replacement for shotgun pellets used in waterfowl hunting, although shotshells made from bismuth are nearly ten times the cost of lead.

=== Opium ===
Lead-contaminated [[opium]] has been the source of poisoning in Iran and other Middle Eastern countries. This has also appeared in the illicit narcotic supply in North America, resulting in confirmed lead poisoning.<ref>{{cite journal | vauthors = Young S, Chen L, Palatnick W, Wong P, Wong J | title = Led Astray | journal = The New England Journal of Medicine | volume = 383 | issue = 6 | pages = 578–583 | date = August 2020 | pmid = 32757528 | doi = 10.1056/NEJMcps1900799 | s2cid = 221017132 | editor-first = Caren G. | editor-last = Solomon }}</ref>


=== Cannabis ===
In 2007, a mass poisoning due to adulterated [[marijuana]] was uncovered in Leipzig, Germany, where 29 young adults were hospitalized with lead poisoning for several months after having smoked marijuana that had been tainted with small lead particles. One hypothesis from the police was that lead, with its high specific gravity, was used to increase the weight of street marijuana sold by the gram, thereby maximizing the dealers' profits. The researchers estimated that the profit per kilogram increased by as much as $1,500 with the lead added. It is common for drugs to be cut with less-expensive substances to increase the profits of dealers or distributors (e.g., cocaine is routinely adulterated with sugars, talcum powder, magnesium salts, and even other drugs). It is thought that the adverse reactions to many of these drugs are a result of poor manufacturing rather than face-value overdoses.<ref>{{cite web|url=https://abcnews.go.com/Health/Drugs/story?id=4622149&page=1|title=Lead-Tainted Marijuana Poisons Users|website=[[ABC News (United States)|ABC News]] }}</ref><ref>{{cite journal |vauthors=Busse FP, Fiedler GM, Leichtle A, Hentschel H, Stumvoll M |title=Lead poisoning due to adulterated marijuana in leipzig |journal=Dtsch Ärztebl Int |volume=105 |issue=44 |pages=757–62 |date=October 2008 |pmid=19623274 |pmc=2696942 |doi=10.3238/arztebl.2008.0757}}</ref>

Besides adulteration, [[cannabis]] plants have an inherent ability to absorb heavy metals from the soil. This makes them useful for remediating contaminated sites. But this may also make cannabis dangerous for consumers who ingest it. Some cannabis strains have been bred specifically to remove pollutants from soil, air, or water, a method known as [[phytoremediation]].<ref>{{cite web|url=https://www.sciencedaily.com/releases/2021/12/211216150039.htm|title=Cannabis may contain heavy metals and affect consumer health, study finds}}</ref>

In 2022, around 40% of cannabis products sold at unlicensed storefronts in New York City were found to contain heavy metals (e.g., lead, nickel), pesticides, and bacteria.<ref>{{cite web|url=https://www.cbsnews.com/news/cannabis-unlicensed-weed-e-coli-lead-and-salmonella-study-finds/|title=Unlicensed weed tainted with E. coli, lead and salmonella, study finds|website=[[CBS News]] |date=December 2022 }}</ref>

==Toxicokinetics==
[[File:Tera-ethyl-lead-chemical.png|right|thumb|[[Tetraethyllead]], still used as an additive in some fuels, can be absorbed through the skin.<ref name="Patrick06"/>{{ums|date=December 2017}} |alt=Two chemical diagrams of tetra-ethyl lead, or (CH3CH2)4Pb. On the left one, carbon and hydrogen are labeled, on the right, they are shown as lines only.]]
[[Toxicokinetics]] describes how the body handles the toxin over time, including absorption, distribution, metabolism, and excretion.

<!-- MEANS OF ABSORPTION -->
Exposure occurs through [[inhalation]], [[ingestion]], or occasionally skin contact. Lead may be taken in through direct contact with the mouth, nose, and eyes (mucous membranes), and breaks in the skin. [[Tetraethyllead]], which was a gasoline additive and is still used in [[aviation gasoline]], passes through the skin; and other forms of lead, including inorganic lead<ref>{{cite journal |last1=Niemeier |first1=Richard Todd |last2=Maier |first2=Andrew |last3=Reichard |first3=John F |title=Rapid Review of Dermal Penetration and Absorption of Inorganic Lead Compounds for Occupational Risk Assessment |journal=Annals of Work Exposures and Health |date=1 April 2022 |volume=66 |issue=3 |pages=291–311 |doi=10.1093/annweh/wxab097 |pmid=35051994 |pmc=8930439 |url=https://academic.oup.com/annweh/article/66/3/291/6433554 |issn=2398-7308}}</ref> are also absorbed through skin.<ref>{{cite book |last1=Castellino |first1=Nicolo |last2=Sannolo |first2=Nicola |last3=Castellino |first3=Pietro |title=Inorganic Lead Exposure and Intoxications |date=22 November 1994 |publisher=CRC Press |isbn=978-0-87371-997-1 |pages=141–142 |url=https://books.google.com/books?id=059oObc8X48C&pg=PA142 |language=en}}</ref> The main sources of absorption of inorganic lead are from ingestion and inhalation.<ref name="Merrill07">[[#CITEREFMerrill07|Merrill, Morton, Soileau (2007)]] p. 860</ref> In adults, about 35–40% of inhaled lead dust is deposited in the lungs, and about 95% of that goes into the bloodstream.<ref name="Merrill07"/> Of ingested inorganic lead, about 15% is absorbed, but this percentage is higher in children, pregnant women, and people with deficiencies of calcium, zinc, or iron.<ref name="Karri08"/> Infants may absorb about 50% of ingested lead, but little is known about absorption rates in children.<ref name="Grant09-767">[[#CITEREFGrant09|Grant (2009)]] p. 767</ref>

<!--STORAGE -->
The main body tissues that store lead are the blood, soft tissues, and bone; the half-life of lead in these tissues is measured in weeks for blood, months for soft tissues, and years for bone.<ref name="Karri08"/> Lead in the bones, teeth, hair, and nails is bound tightly and not available to other tissues, and is generally thought not to be harmful.<ref name="Rubin08">[[#CITEREFRubin08|Rubin, Strayer (2008)]] p. 266</ref> In adults, 94% of absorbed lead is deposited in the bones and teeth, but children only store 70% in this manner, a fact which may partially account for the more serious health effects on children.<ref name="Barbosa"/> The half-life of lead in bone has been estimated as years to decades, and bone can introduce lead into the bloodstream long after the initial exposure is gone.<ref name="CDC Lead Biomonitoring Summary">{{cite news |title=Biomonitoring Summary, Lead |url=https://www.cdc.gov/biomonitoring/Lead_BiomonitoringSummary.html |access-date=3 February 2021 |publisher=CDC |date=7 April 2017}}</ref><ref name="Kosnett et al., JAMA 1994">{{cite journal |last1=Kosnett |first1=Michael J |last2=Becker |first2=CE |last3=Osterloh |first3=JD |last4=Kelly |first4=TJ |last5=Pasta |first5=DJ |title=Factors influencing bone lead concentration in a suburban community assessed by noninvasive K x-ray fluorescence. |journal=JAMA |date=19 January 1994 |volume=271 |issue=3 |pages=197–203 |doi=10.1001/jama.1994.03510270043037 |pmid=8277545 |url=https://pubmed.ncbi.nlm.nih.gov/8277545/ |access-date=3 February 2021}}</ref><ref name="Rabinowitz, Env Health Persp 1991">{{cite journal |last1=Rabinowitz |first1=Michael B. |title=Toxicokinetics of bone lead. |journal=Environmental Health Perspectives |date=February 1991 |volume=91 |pages=33–7 |doi=10.1289/ehp.919133 |pmid=2040248|pmc=1519353 |bibcode=1991EnvHP..91...33R }}</ref> The half-life of lead in the blood in men is about 40 days, but it may be longer in children and pregnant women, whose bones are undergoing [[bone remodeling|remodeling]], which allows the lead to be continuously re-introduced into the bloodstream.<ref name="Barbosa"/> Also, if lead exposure takes place over the years, clearance is much slower, partly due to the re-release of lead from bone.<ref name="Hu07"/> Many other tissues store lead, but those with the highest concentrations (other than blood, bone, and teeth) are the brain, spleen, kidneys, liver, and lungs.<ref name="Dart041426">[[#CITEREFDart04|Dart, Hurlbut, Boyer-Hassen (2004)]] p. 1426</ref>
<!--
EXCRETION
-->Lead is removed from the body very slowly, mainly through urine.<ref name="Pearson03"/> Smaller amounts of lead are also eliminated through the feces, and very small amounts in hair, nails, and sweat.<ref name="Kosnett06-238"/>

==Toxicodynamics==
[[Toxicodynamics]] describes how the toxin affects the body, including the mechanisms causing its symptoms.
<!--
HARMFUL EFFECTS -->
Lead has no known physiologically necessary role in the body,<ref name="White07">{{cite journal | vauthors = White LD, Cory-Slechta DA, Gilbert ME, Tiffany-Castiglioni E, Zawia NH, Virgolini M, Rossi-George A, Lasley SM, Qian YC, Basha MR | title = New and evolving concepts in the neurotoxicology of lead | journal = Toxicology and Applied Pharmacology | volume = 225 | issue = 1 | pages = 1–27 | date = November 2007 | pmid = 17904601 | doi = 10.1016/j.taap.2007.08.001 | bibcode = 2007ToxAP.225....1W }}</ref><ref name="Mañay08">{{cite book | vauthors = Mañay N, Cousillas AZ, Alvarez C, Heller T | title = Reviews of Environmental Contamination and Toxicology | chapter = Lead Contamination in Uruguay: The "La Teja" Neighborhood Case | volume = 195 | pages = 93–115 | year = 2008 | pmid = 18418955 | doi = 10.1007/978-0-387-77030-7_4 | isbn = 978-0-387-77029-1 }}</ref> and its harmful effects are myriad. Lead and other heavy metals create reactive [[free radical|radicals]] which damage cell structures, including [[DNA]] and [[cell membrane]]s.<ref name="Flora08">{{cite journal | vauthors = Flora SJ, Mittal M, Mehta A | title = Heavy metal induced oxidative stress & its possible reversal by chelation therapy | journal = The Indian Journal of Medical Research | volume = 128 | issue = 4 | pages = 501–23 | date = October 2008 | pmid = 19106443 }}</ref> Lead also interferes with [[Transcription (genetics)|DNA transcription]], [[enzyme]]s that help in the synthesis of [[vitamin D]], and enzymes that maintain the integrity of the [[cell membrane]].<ref name="Dart041426"/> Anemia may result when the cell membranes of [[red blood cell]]s become more fragile as a result of damage to their membranes.<ref name="Yu05-193">[[#CITEREFYu05|Yu (2005)]] p.193</ref> Lead interferes with metabolism of bones and teeth<ref name="Casarett07-946"/> and alters the permeability of blood vessels and [[collagen]] synthesis.<ref name="Need2004" /> Lead may also be harmful to the developing [[immune system]], causing production of excessive [[inflammation|inflammatory]] proteins; this mechanism may mean that lead exposure is a risk factor for [[asthma]] in children.<ref name="Casarett07-946">[[#CITEREFCasarett07|Casarett, Klaassen, Doull (2007)]] p. 946</ref> Lead exposure has also been associated with a decrease in activity of immune cells such as [[polymorphonuclear leukocyte]]s.<ref name="Casarett07-946"/> Lead also interferes with the normal metabolism of [[calcium in biology|calcium in cells]] and causes it to build up within them.<ref name="Chisolm04-222"/>

===Enzymes===
[[File:196-Lead Poisoning-1qnv.tif|thumb|right|[[Delta-aminolevulinic acid dehydratase|ALAD enzyme]] with lead bound ({{PDB|1QNV}})]]
The primary cause of lead's toxicity is its interference with a variety of enzymes because it binds to [[sulfhydryl group]]s found on many enzymes.<ref name="Pearson03"/> Part of lead's toxicity results from its ability to mimic other metals that take part in biological processes, which act as [[cofactor (biochemistry)|cofactor]]s in many enzymatic reactions, displacing them at the enzymes on which they act.<ref name="Dart041426"/> Lead can bind to and interact with many of the same [[enzyme]]s as these metals but, due to its differing chemistry, does not properly function as a cofactor, thus interfering with the enzyme's ability to catalyze its normal reaction or reactions. Among the essential metals that lead displaces in this way are calcium, iron, and zinc.<ref name="Kosnett06-238">[[#CITEREFKosnett06Pois|Kosnett (2006)]] p.238</ref>

The lead ion has a [[lone pair]] in its electronic structure, which can result in a distortion in the [[Coordination complex|coordination]] of [[ligand]]s, and in 2007 was hypothesized to be important in lead poisoning's effects on enzymes (see {{section link|Lone pair|Unusual lone pairs}}).<ref>{{cite journal | vauthors = Gourlaouen C, Parisel O | title = Is an electronic shield at the molecular origin of lead poisoning? A computational modeling experiment | journal = Angewandte Chemie | volume = 46 | issue = 4 | pages = 553–6 | date = 15 January 2007 | pmid = 17152108 | doi = 10.1002/anie.200603037 }}</ref>

<!-- HEME -->
One of the main causes for the pathology of lead is that it interferes with the activity of an essential enzyme called [[delta-aminolevulinic acid dehydratase]], or ALAD (see image of the enzyme structure), which is important in the biosynthesis of [[heme]], the cofactor found in [[hemoglobin]].<ref>{{cite journal | vauthors = Jaffe EK, Martins J, Li J, Kervinen J, Dunbrack RL | title = The molecular mechanism of lead inhibition of human porphobilinogen synthase | journal = The Journal of Biological Chemistry | volume = 276 | issue = 2 | pages = 1531–7 | date = January 2001 | pmid = 11032836 | doi = 10.1074/jbc.M007663200 | s2cid = 38826214 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Scinicariello F, Murray HE, Moffett DB, Abadin HG, Sexton MJ, Fowler BA | title = Lead and delta-aminolevulinic acid dehydratase polymorphism: where does it lead? A meta-analysis | journal = Environmental Health Perspectives | volume = 115 | issue = 1 | pages = 35–41 | date = January 2007 | pmid = 17366816 | pmc = 1797830 | doi = 10.1289/ehp.9448 | bibcode = 2007EnvHP.115...35S }}</ref><ref>{{cite web|last1=Chhabra |first1=Namrata |title=Effect of Lead poisoning on heme biosynthetic pathway |url=http://usmle.biochemistryformedics.com/effect-of-lead-poisoning-on-heme-biosynthetic-pathway/ |website=Clinical Cases: Biochemistry For Medics |access-date=30 October 2016 |archive-url=https://web.archive.org/web/20160403160650/http://usmle.biochemistryformedics.com/effect-of-lead-poisoning-on-heme-biosynthetic-pathway/ |archive-date= 3 April 2016 |date=November 15, 2015 |url-status=dead }}</ref> Lead also inhibits the enzyme [[ferrochelatase]], another enzyme involved in the formation of heme.<ref name="Barbosa"/><ref name="pmid12498316">{{cite journal | vauthors = Fujita H, Nishitani C, Ogawa K | title = Lead, chemical porphyria, and heme as a biological mediator | journal = The Tohoku Journal of Experimental Medicine | volume = 196 | issue = 2 | pages = 53–64 | date = February 2002 | pmid = 12498316 | doi = 10.1620/tjem.196.53 | doi-access = free }}</ref> Ferrochelatase catalyzes the joining of [[protoporphyrin]] and [[Iron|Fe<sup>2+</sup>]] to form heme.<ref name="Barbosa"/><ref name="Dart041426"/> Lead's interference with heme synthesis results in production of [[zinc protoporphyrin]] and the development of [[anemia]].<ref name="Mycyk05-462">[[#CITEREFMycyk05|Mycyk, Hryhorczuk, Amitai (2005)]] p. 462</ref> Another effect of lead's interference with heme synthesis is the buildup of heme precursors, such as [[aminolevulinic acid]], which may be directly or indirectly harmful to neurons.<ref name="Kosnett05-822"/> Elevation of aminolevulinic acid results in lead poisoning, having symptoms similar to [[Porphyria#Acute porphyrias|acute porphyria]].<ref>{{cite book |last=Vannotti |first=Alfred |date=1954 |title=Porphyrins: Their Biological and Chemical Importance |url=https://books.google.com/books?id=-bzoAAAAIAAJ |publisher=Hilger & Watts, Hilger Division |page=126 |quote=Indeed, lead poisoning, like all porphyrin diseases, is accompanied by obstinate constipation, nervous lesions, hyperpigmentation, and abdominal attacks. }}</ref><ref>{{cite book|last1=Dancygier|first1=Henryk |title=Clinical Hepatology: Principles and Practice of Hepatobiliary Diseases|date=2009|publisher=Springer Science & Business Media|isbn=978-3-642-04519-6|page=1088|url=https://books.google.com/books?id=lrPX8C4p90QC&pg=PA1088|url-status=live|archive-url=https://web.archive.org/web/20170908185104/https://books.google.com/books?id=lrPX8C4p90QC&pg=PA1088|archive-date=8 September 2017|df=dmy-all}}</ref><ref>{{cite journal | vauthors = Akshatha LN, Rukmini MS, Mamatha TS, Sadashiva Rao P, Prashanth B | title = Lead poisoning mimicking acute porphyria! | journal = Journal of Clinical and Diagnostic Research | volume = 8 | issue = 12 | pages = CD01-2 | date = December 2014 | pmid = 25653942 | pmc = 4316248 | doi = 10.7860/JCDR/2014/10597.5315 }}</ref><ref>{{cite journal | vauthors = Tsai MT, Huang SY, Cheng SY | title = Lead Poisoning Can Be Easily Misdiagnosed as Acute Porphyria and Nonspecific Abdominal Pain | journal = Case Reports in Emergency Medicine | volume = 2017 | page = 9050713 | date = 2017 | pmid = 28630774 | pmc = 5467293 | doi = 10.1155/2017/9050713 | doi-access = free }}</ref><ref>{{cite journal | title = Hereditary Coproporphyria | journal = GeneReviews | date = 2018 | pmid = 23236641 | url = https://www.ncbi.nlm.nih.gov/books/NBK114807/ | access-date = 28 February 2020 | quote = the symptoms in lead poisoning closely mimic those of acute porphyria | last1 = Wang | first1 = B. | last2 = Bissell | first2 = D. M. | last3 = Adam | first3 = M. P. | last4 = Ardinger | first4 = H. H. | last5 = Pagon | first5 = R. A. | last6 = Wallace | first6 = S. E. | author7 = Bean LJH | last8 = Stephens | first8 = K. | last9 = Amemiya | first9 = A. }}</ref>

===Neurons===
[[File:Lead-exposed rat hippocampi.jpg|thumb|right|Lead exposure damages cells in the [[hippocampus]], a part of the brain involved in memory. Hippocampi of lead-exposed rats (bottom) show structural damage such as irregular nuclei (IN) and denaturation of [[myelin]] (DMS) compared to controls (top).<ref name="Xu09"/>|alt=Two black-and-white photos; one shows dark, fairly regular rings on a lighter background, and the other shows irregular, smaller, and not as dark clusters.]]

<!-- CNS DEVELOPMENT -->
The brain is the organ most sensitive to lead exposure.<ref name="Cecil08"/> Lead can pass through the endothelial cells at the [[blood brain barrier]] because it can substitute for [[calcium|calcium ions]] and be taken up by [[Plasma membrane Ca2+ ATPase|calcium-ATPase pumps]].<ref>{{cite journal | vauthors = Lidsky TI, Schneider JS | title = Lead neurotoxicity in children: basic mechanisms and clinical correlates | journal = Brain | volume = 126 | issue = Pt 1 | pages = 5–19 | date = January 2003 | pmid = 12477693 | doi = 10.1093/brain/awg014 | doi-access = free }}</ref> Lead poisoning interferes with the normal development of a child's brain and [[nervous system]]; therefore children are at greater risk of lead [[neurotoxicity]] than adults are.<ref name="Sanders09">{{cite journal | vauthors = Sanders T, Liu Y, Buchner V, Tchounwou PB | title = Neurotoxic effects and biomarkers of lead exposure: a review | journal = Reviews on Environmental Health | volume = 24 | issue = 1 | pages = 15–45 | year = 2009 | pmid = 19476290 | pmc = 2858639 | doi = 10.1515/REVEH.2009.24.1.15 | bibcode = 2009RvEH...24.1.15S }}</ref> In a child's developing brain, lead interferes with [[synapse]] formation <!-- "syaptic modeling" --> in the [[cerebral cortex]], [[neurochemical]] development (including that of neurotransmitters), and organization of [[ion channel]]s.<ref name="Mycyk05-462"/> It causes loss of neurons' [[myelin]] sheaths, reduces the numbers of neurons, interferes with neurotransmission, and decreases neuronal growth.<ref name="Pearson03"/>

<!-- NMDA-Receptor -->
Lead ions (Pb{{sup|2+}}), like magnesium ions (Mg{{sup|2+}}), block [[NMDA receptor]]s. Therefore, an increase in Pb{{sup|2+}} concentration will effectively inhibit ongoing [[long-term potentiation]] (LTP), and lead to an abnormal increase in [[long-term depression]] (LTD) on [[neuron]]s in the affected parts of [[Nervous system|the nervous system]]. These abnormalities lead to the indirect [[Downregulation and upregulation|downregulation]] of NMDA-receptors, effectively initiating a [[Positive feedback#In biology|positive feedback-loop]] for LTD.<ref>{{cite web|url=http://www.jhsph.edu/publichealthnews/press_releases/PR_2000/lead_change.html|work=Johns Hopkins Bloomberg School of Public Health|title=How Lead Changes the Brain to Impair Learning and Memory, How Lead Changes the Brain to Impair Learning and Memory|date=3 August 2000 |access-date=2007-08-14|url-status=live|archive-url=https://web.archive.org/web/20070816100857/http://www.jhsph.edu/PublicHealthNews/Press_Releases/PR_2000/lead_change.html|archive-date=2007-08-16}}</ref> The targeting of NMDA receptors is thought to be one of the main causes for lead's [[neurotoxicity|toxicity to neurons]].<ref name="Xu09">{{cite journal | vauthors = Xu J, Yan HC, Yang B, Tong LS, Zou YX, Tian Y | title = Effects of lead exposure on hippocampal metabotropic glutamate receptor subtype 3 and 7 in developmental rats | journal = Journal of Negative Results in Biomedicine | volume = 8 | page = 5 | date = April 2009 | pmid = 19374778 | pmc = 2674876 | doi = 10.1186/1477-5751-8-5 | doi-access = free }}</ref>

==Diagnosis==
Diagnosis includes determining the clinical signs and the medical history, with inquiry into possible routes of exposure.<ref name="Henretig061316">[[#CITEREFHenretig06|Henretig (2006)]] p. 1316</ref> [[medical toxicology|Clinical toxicologists]], medical specialists in the area of poisoning, may be involved in diagnosis and treatment.
<!-- BLOOD LEAD LEVEL -->
The main tool in diagnosing and assessing the severity of lead poisoning is laboratory analysis of the [[blood lead level]] (BLL).<ref name="Mycyk05-463">[[#CITEREFMycyk05|Mycyk, Hryhorczuk, Amitai (2005)]] p. 463</ref>
<!--
OTHER BLOOD -->
[[File:Lead poisoning - blood film.jpg|left|thumb|[[Basophilic stippling]] (arrows) of red [[blood cells]] in a 53-year-old who had elevated blood lead levels due to drinking repeatedly from glasses decorated with lead paint.<ref>{{cite web|url=http://cnx.org/content/m15003/latest/ |vauthors=Fred HL, van Dijk HA |title=Images of Memorable Cases: Case 81|publisher=Connexions|access-date=August 25, 2009}}</ref>|alt=dozens of pink circular bodies with white centers on a white background. Arrows point to three of the cells; two are speckled with dark purple dots, and the third has an irregular outer border]]

[[Blood film]] examination may reveal [[basophilic stippling]] of [[red blood cells]] (dots in red blood cells visible through a microscope), as well as the changes normally associated with iron-deficiency anemia ([[microcytosis]] and [[hypochromic|hypochromasia]]).<ref name="Rubin08-267"/> This may be known as [[sideroblastic anemia]].<ref>{{cite journal | vauthors = Lubran MM | title = Lead toxicity and heme biosynthesis | journal = Annals of Clinical and Laboratory Science | volume = 10 | issue = 5 | pages = 402–13 | date = 1980 | pmid = 6999974 }}</ref> However, basophilic stippling is also seen in unrelated conditions, such as [[megaloblastic anemia]] caused by [[vitamin B12]] (cobalamin) and [[folate]] deficiencies.<ref>{{cite book | vauthors = Fischer C |title=Kaplan Medical USMLE Steps 2 and 3 Notes: Internal Medicine, Hematology |pages=176–177 |year=2007}}</ref>
Contrary to other sideroblastic anemias, there are no ring sideroblasts in a bone marrow smear.<ref>{{cite book | vauthors = Bottomley SS | chapter = Sideroblastic Anemias | veditors = Greer JP, Arber DA, Glader BE, List AF, Means RT, Paraskevas F, Rodgers GM, Wintrobe MM | title = Wintrobe's Clinical Hematology |date=2014 |isbn=978-1-4511-7268-3 |page=657 |edition=Thirteenth | publisher = Lippincott Williams & Wilkins }}</ref>

Exposure to lead can also be evaluated by measuring [[zinc protoporphyrin|erythrocyte protoporphyrin]] (EP) in blood samples.<ref name="Patrick06"/>{{ums|date=December 2017}} EP is a part of red blood cells known to increase when the amount of lead in the blood is high, with a delay of a few weeks.<ref name="Kosnett05-825"/> Thus EP levels in conjunction with blood lead levels can suggest the period of exposure; if blood lead levels are high but EP is still normal, this finding suggests exposure was recent.<ref name="Kosnett05-825"/><ref name="Kosnett06-240"/> However, the EP level alone is not sensitive enough to identify elevated blood lead levels below about 35&nbsp;μg/dL.<ref name="Patrick06"/>{{ums|date=December 2017}} Due to this higher threshold for detection and the fact that EP levels also increase in [[Iron deficiency (medicine)|iron deficiency]], use of this method for detecting lead exposure has decreased.<ref name="Grant09-784">[[#CITEREFGrant09|Grant (2009)]] p. 784</ref>

<!-- BONE -->
Blood lead levels are an indicator mainly of recent or current lead exposure, not of total [[body burden]].<ref name="Vaziri08-AmJPhys">{{cite journal | vauthors = Vaziri ND | title = Mechanisms of lead-induced hypertension and cardiovascular disease | journal = American Journal of Physiology. Heart and Circulatory Physiology | volume = 295 | issue = 2 | pages = H454-65 | date = August 2008 | pmid = 18567711 | pmc = 2519216 | doi = 10.1152/ajpheart.00158.2008 }}</ref> Lead in bones can be measured [[Invasiveness of surgical procedures|noninvasively]] by [[X-ray fluorescence]]; this may be the best measure of cumulative exposure and total body burden.<ref name="Kosnett06-240"/> However, this method is not widely available and is mainly used for research rather than routine diagnosis.<ref name="Brodkin07-CMAJ"/> Another radiographic sign of elevated lead levels is the presence of [[radiodensity|radiodense]] lines called lead lines at the [[metaphysis]] in the long bones of growing children, especially around the knees.<ref name="Mycyk05-464">[[#CITEREFMycyk05|Mycyk, Hryhorczuk, Amitai (2005)]] p. 464</ref> These lead lines, caused by increased [[calcification]] due to disrupted metabolism in the growing bones, become wider as the duration of lead exposure increases.<ref name="Mycyk05-464"/> [[X-rays]] may also reveal lead-containing foreign materials such as paint chips in the gastrointestinal tract.<ref name="Katzung07-948">[[#CITEREFKatzung07|Kosnett (2007)]] p. 948</ref><ref name="Mycyk05-464"/>

<!-- FECES -->
Fecal lead content that is measured over a few days may also be an accurate way to estimate the overall amount of childhood lead intake. This form of measurement may serve as a useful way to see the extent of oral lead exposure from all the dietary and environmental sources of lead.<ref name="Gwiazda04">{{cite journal | vauthors = Gwiazda R, Campbell C, Smith D | title = A noninvasive isotopic approach to estimate the bone lead contribution to blood in children: implications for assessing the efficacy of lead abatement | journal = Environmental Health Perspectives | volume = 113 | issue = 1 | pages = 104–10 | date = January 2005 | pmid = 15626656 | pmc = 1253718 | doi = 10.1289/ehp.7241 | bibcode = 2005EnvHP.113..104G }}</ref>

<!-- DIF DX -->
Lead poisoning shares symptoms with other conditions and may be easily missed.<ref name="Brunton07-31"/> Conditions that present similarly and must be ruled out in diagnosing lead poisoning include [[carpal tunnel syndrome]], [[Guillain–Barré syndrome]], [[renal colic]], [[appendicitis]], [[encephalitis]] in adults, and [[viral gastroenteritis]] in children.<ref name="Henretig061316"/> Other [[differential diagnosis|differential diagnoses]] in children include [[constipation]], abdominal colic, iron deficiency, [[subdural hematoma]], [[neoplasm]]s of the central nervous system, emotional and behavior disorders, and [[intellectual disability]].<ref name="Mycyk05-463"/>

===Reference levels===
The current reference range for acceptable blood lead concentrations in healthy persons without excessive exposure to environmental sources of lead is less than 3.5&nbsp;μg/dL for children.<ref name=CDC2012/> It was less than 25&nbsp;μg/dL for adults.<ref>Wu, A. (2006) ''Tietz Clinical Guide to Laboratory Tests'', 4th ed., Saunders Elsevier, St. Louis, MO, pp. 658–659.</ref> Previous to 2012, the value for children was 10 (μg/dL).<ref name="cdc.gov">{{cite web|title=Low Level Lead Exposure Harms Children: A Renewed Call for Primary Prevention|url=https://www.cdc.gov/nceh/lead/ACCLPP/Final_Document_010412.pdf |work= U.S. Centers for Disease Control and Prevention|access-date=5 January 2012|url-status=live|archive-url= https://web.archive.org/web/20120109064513/http://www.cdc.gov/nceh/lead/ACCLPP/Final_Document_010412.pdf |archive-date=9 January 2012}}</ref> Lead-exposed workers in the US are required to be removed from work when their level is greater than 50&nbsp;μg/dL if they do construction and otherwise greater than 60&nbsp;μg/dL.<ref>{{cite web |title=CDC - Adult Blood Lead Epidemiology and Surveillance (ABLES): Program Description: NIOSH Workplace Safety and Health Topic |url=https://www.cdc.gov/niosh/topics/ables/description.html |website=www.cdc.gov |access-date=31 October 2019|date=28 November 2018}}</ref>

In 2015, the US Health and Human Services (HHS), Centers for Disease Control and Prevention (CDC), and National Institute for Occupational Safety and Health (NIOSH) designated 5&nbsp;μg/dL (five micrograms per deciliter) of whole blood, in a venous blood sample, as the reference blood lead level for adults. An elevated blood lead level (BLL) is defined as a BLL ≥5&nbsp;μg/dL. This case definition is used by the [[Adult Blood Lead Epidemiology and Surveillance]] (ABLES) program, the Council of State and Territorial Epidemiologists (CSTE), and the CDC's National Notifiable Diseases Surveillance System (NNDSS). Previously (i.e., from 2009 until November 2015), the case definition for an elevated BLL was a BLL ≥10&nbsp;μg/dL.<ref name="NIOSH2015">{{cite web |url=https://www.cdc.gov/niosh/topics/ables/description.html |title=CDC - Adult Blood Lead Epidemiology and Surveillance (ABLES): Program Description: NIOSH Workplace Safety and Health Topic |author=<!--Not stated--> |date=2017-08-10 |website=The National Institute for Occupational Safety and Health (NIOSH) |publisher=US Center for Disease Control |access-date= 2017-11-19}}</ref> The US national BLL geometric mean among adults was 1.2&nbsp;μg/dL in 2009–2010.<ref>{{cite web |publisher= cdc.gov |title= Fourth National Report on Human Exposure to Environmental Chemicals. Updated Tables |date= September 2012 |location= Atlanta, GA |work= US Department of Health and Human Services |url= https://www.cdc.gov/exposurereport/pdf/FourthReport_UpdatedTables_Sep2012.pdf |url-status=live |archive-url= https://web.archive.org/web/20170501131121/https://www.cdc.gov/exposurereport/pdf/FourthReport_UpdatedTables_Sep2012.pdf |archive-date= 2017-05-01 }}</ref>

Blood lead concentrations in poisoning victims have ranged from 30 to 80&nbsp;μg/dL in children exposed to lead paint in older houses, 77–104&nbsp;μg/dL in persons working with pottery glazes, 90–137&nbsp;μg/dL in individuals consuming contaminated herbal medicines, 109–139&nbsp;μg/dL in indoor shooting range instructors and as high as 330&nbsp;μg/dL in those drinking fruit juices from glazed earthenware containers.<ref>{{cite book |first=Randall Clint |last=Baselt |title=Disposition of Toxic Drugs and Chemicals in Man |year=2008 |publisher=Biomedical Publications |isbn=978-0-9626523-7-0 |edition=8th |pages=823–6}}</ref>

==Prevention==
[[File:Lead testing.jpg|thumb|upright=1.4|Testing kits are commercially available for detecting lead. These swabs, when wiped on a surface, turn red in the presence of lead.|alt=A box of cigarette-like white cylinders on the left, in the middle a white cylinder with a pink tip, on the right a paper with four circles, two blank and two pink]]
{{see also|Lead#Restriction_and_remediation |Lead abatement in the United States}}

Prevention for lead poisoning can be divided into primary, secondary, and tertiary prevention methods.

===Primary prevention===
Primary prevention of lead poisoning aims to address the root cause of the problem before any adverse health outcomes occur.<ref name="CDC - Preventing Childhood Lead Poisoning">{{cite web |title=Preventing Childhood Lead Poisoning |url=https://www.cdc.gov/lead-prevention/prevention/index.html#:~:text=Primary%20prevention%20is%20the%20removal,term%20effects%20of%20lead%20exposure. |website=cdc.gov | date=31 January 2025 |access-date=23 March 2025}}</ref> This can be achieved through an attempt to remove the sources of lead poisoning (either by government, corporations, or individuals) or by educating individuals and communities about lead exposure, its sources, and its health impacts which can help prevent lead poisoning from happening in the first place.<ref>{{cite journal |last1=Ettinger |first1=Adrienne |last2=Leonard |first2=Monica |last3=Mason |first3=Jacquelyn |title=CDC's Lead Poisoning Prevention Program: A Long-standing Responsibility and Commitment to Protect Children From Lead Exposure |journal=J Public Health Manag Pract |date=5 January 2019 |volume=Jan-Feb |issue=25 |pages=S5–S12 |doi=10.1097/PHH.0000000000000868 |pmid=30507764 |pmc=6320665 }}</ref>

''Lead pipe replacement''

Lead pipe replacement is one of the most effective ways to reduce lead in water, as lead service lines are the leading drinking water contamination source.<ref>{{cite journal |last1=Sansom |first1=Garett |last2=Cizmas |first2=Leslie |last3=Aarvig |first3=Kathleen |last4=Dixon |first4=Benika |last5=Kirsch |first5=Katie |last6=Katare |first6=Anjali |last7=Sansom |first7=Lindsay |title=Vulnerable Populations Exposed to Lead-Contaminated Drinking Water within Houston Ship Channel Communities |journal=Int J Environ Res Public Health |date=1 August 2019 |volume=16 |issue=15 |page=2745 |doi=10.3390/ijerph16152745 |doi-access=free |pmid=31374814 |pmc=6695821 }}</ref><ref>{{cite journal |last1=Vijayashanthar |first1=Vasikan |last2=Small |first2=Mitchell |last3=VanBriesen |first3=Jeanne |title=Assessment of Lead in Drinking Water from Multiple Drinking Water Sampling Programs for a Midsize CityArticle link copied! |journal=Environmental Science & Technology |date=23 December 2022 |volume=57 |issue=1 |pages=842–851 |doi=10.1021/acs.est.2c06614 |url=https://pubs.acs.org/doi/10.1021/acs.est.2c06614|pmc=9835881 }}</ref> Replacement of lead service lines has been shown to drastically reduce lead levels in water.<ref>{{cite journal |last1=Zahran |first1=Sammy |last2=Mushinski |first2=David |last3=McElmurry |first3=Shawn |last4=Keyes |first4=Christopher |title=Water lead exposure risk in Flint, Michigan after switchback in water source: Implications for lead service line replacement policy |journal=Environ. Res. |date=1 February 2020 |volume=181 |issue=108928 |doi=10.1016/j.envres.2019.108928 |pmid=31787215 |pmc=7096221 |bibcode=2020ER....18108928Z }}</ref> When considering lead line replacement as a primary prevention method, it is essential to specify the need for complete replacement versus partial replacement as partial replacement of lead service lines can disturb/dislodge lead in unreplaced portions of the pipe, leading to increased concentrations of lead in water.<ref>{{cite journal |last1=St Clair |first1=Justin |last2=Cartier |first2=Clement |last3=Triantafyllidou |first3=Simoni |last4=Clark |first4=Brandi |last5=Edwards |first5=Marc |title=Long-Term Behavior of Simulated Partial Lead Service Line Replacements |journal=Environ Eng Sci. |date=1 January 2016 |volume=33 |issue=1 |pages=53–64 |doi=10.1089/ees.2015.0337 |pmid=26989344 |pmc=4770854 |bibcode=2016EEngS..33...53S }}</ref>

''Education''

The education of workers on lead, its danger, and how its workplace exposure can be decreased, especially when initial blood lead level and urine lead level are high, could help reduce the risk of lead poisoning in the workplace.<ref name=":0" />

''Additional primary prevention''

Recommended steps by individuals to reduce the blood lead levels of children include increasing their frequency of hand washing and their intake of calcium and iron, discouraging them from putting their hands to their mouths, vacuuming frequently, and eliminating the presence of lead-containing objects such as blinds and jewellery in the house.<ref name="Payne08"/> In houses with lead pipes or plumbing solder, these can be replaced.<ref name="Payne08"/> Less permanent but cheaper methods include running water in the morning to flush out the most contaminated water, or adjusting the water's chemistry to prevent corrosion of pipes.<ref name="Payne08"/> Lead testing kits are commercially available for detecting the presence of lead in the household.<ref name="cr">{{cite web|url=https://www.consumerreports.org/lead-test-kits/how-to-test-paint-with-a-lead-test-kit/|publisher=[[Consumer Reports]]|title=How to Test Paint With a DIY Lead Test Kit: CR's step-by-step guide to getting accurate results from 3M LeadCheck and D-Lead|date=15 October 2017 |access-date=2021-02-12}}</ref><ref name="Salvato03-117">[[#CITEREFSalvato03|Salvato (2003)]] p.117</ref> Testing kit accuracy depends on the user testing all layers of paint and the quality of the kit; the [[United States Environmental Protection Agency|US Environmental Protection Agency]] (EPA) only approves kits with an accuracy rating of at least 95%.<ref name="jse"/><ref>{{cite web|url=https://www.epa.gov/lead/lead-test-kits|title=Lead Test Kits|date=12 February 2013}}</ref> Professional lead testing companies caution that DIY test kits can create health risks for users who do not understand their limitations and liability issues for employers concerning worker protection.<ref name="jse">{{cite web|url=https://jselabs.com/blog/diy-lead-paint-test-kits-explained/|title=DIY Lead Paint Test Kits Explained: Do They Really Work?|date=27 August 2020}}</ref> As hot water is more likely than cold water to contain higher amounts of lead, only cold water from the tap should be used for drinking, cooking, and making baby formula. Since most of the lead in household water usually comes from plumbing in the house and not from the local water supply, using cold water can avoid lead exposure.<ref name="EPH">National Environmental Public Health Tracking Network, 2010.</ref> Measures such as dust control and household education do not appear to be effective in changing children's blood levels.<ref>{{cite journal|last1=Nussbaumer-Streit|first1=Barbara|last2=Mayr|first2=Verena|last3=Dobrescu|first3=Andreea Iulia|last4=Wagner|first4=Gernot|last5=Chapman|first5=Andrea|last6=Pfadenhauer|first6=Lisa M.|last7=Lohner|first7=Szimonetta|last8=Lhachimi|first8=Stefan K.|last9=Busert|first9=Laura K.|last10=Gartlehner|first10=Gerald|date=6 October 2020|title=Household interventions for secondary prevention of domestic lead exposure in children|journal=The Cochrane Database of Systematic Reviews|volume=2020|issue=10 |page=CD006047|doi=10.1002/14651858.CD006047.pub6|issn=1469-493X|pmid=33022752|pmc=8094406}}</ref>

Prevention measures also exist on the national and municipal levels. Recommendations by health professionals for lowering childhood exposures include banning the use of lead where it is not essential and strengthening regulations that limit the amount of lead in soil, water, air, household dust, and products.<ref name="Lanphear05EnvironHealth"/> Regulations exist to limit the amount of lead in paint; for example, a 1978 law in the US restricted the lead in paint for residences, furniture, and toys to 0.06% or less.<ref name="Henretig06"/> In October 2008, the US EPA reduced the allowable lead level by a factor of ten to 0.15 micrograms per cubic meter of air, giving states five years to comply with the standards.<ref>{{cite web|url=http://www.efluxmedia.com/news_EPA_Sets_Tightest_Lead_Air_Emission_Standard_In_Three_Decades_26899.html | vauthors = Chisamera D |title=EPA Sets Tightest Lead Air Emission Standard |date=October 19, 2008 |publisher=eFluxMedia |url-status=dead |archive-url=https://web.archive.org/web/20090604105256/http://www.efluxmedia.com/news_EPA_Sets_Tightest_Lead_Air_Emission_Standard_In_Three_Decades_26899.html |archive-date=June 4, 2009 }}</ref> The European Union's [[Restriction of Hazardous Substances Directive]] limits amounts of lead and other toxic substances in electronics and electrical equipment. In some places, remediation programs exist to reduce the presence of lead when it is found to be high, for example, in drinking water.<ref name="Payne08"/> As a more radical solution, entire towns located near former lead mines have been "closed" by the government, and the population resettled elsewhere, as was the case with [[Picher, Oklahoma]], in 2009.<ref>{{cite news |title =Polluted Kansas Town Seeks Federal Buyout |work =[[All things considered]] |publisher =[[National Public Radio]] |date =August 25, 2009 |url =https://www.npr.org/templates/story/story.php?storyId=112215626 |access-date =August 25, 2009 |url-status =live |archive-url =https://web.archive.org/web/20090827233919/http://www.npr.org/templates/story/story.php?storyId=112215626 |archive-date =August 27, 2009 }}</ref><ref>{{cite web | url = https://www.nytimes.com/2009/09/14/us/14kansas.html | title = Treece Journal: Welcome to Our Town. Wish We Weren't Here | archive-url = https://web.archive.org/web/20130813151006/http://www.nytimes.com/2009/09/14/us/14kansas.html | archive-date=2013-08-13 | vauthors = Saulny S | work = [[The New York Times]] | date = September 13, 2009 }}</ref> Removing lead from [[airplane fuel]] would also be useful.<ref>{{cite web |title=10 Policies to Prevent and Respond to Childhood Lead Exposure |url=http://www.pewtrusts.org/en/research-and-analysis/reports/2017/08/10-policies-to-prevent-and-respond-to-childhood-lead-exposure#1-key-findings | work = The Pew Charitable Trusts |access-date=14 June 2018 |date=30 August 2017}}</ref>

===Secondary prevention===
Secondary prevention of lead poisoning seeks to detect early exposures in individuals and intervene to prevent progression and long-term health complications.<ref>{{cite journal |last1=Sample |first1=Jennifer |title=Lead Exposure in Children: Failure to Protect the Most Vulnerable |journal=J Pediatr Pharmacol Ther. |date=10 June 2024 |volume=29 |issue=3 |pages=212–214 |doi=10.5863/1551-6776-29.3.212 |pmid=38863859 |pmc=11163901 }}</ref>

'''Screening'''

Screening may be an important method of prevention for those at high risk,<ref name="Guidotti07-PedClin"/> such as those who live near lead-related industries.<ref name="Mycyk05-463"/> The [[United States Preventive Services Task Force]] (USPSTF) has stated that general screening of those without symptoms, including children and pregnant women, is of unclear benefit {{as of|2019|lc=y}}.<ref>{{cite journal | vauthors = Curry SJ, Krist AH, Owens DK, Barry MJ, Cabana M, Caughey AB, Doubeni CA, Epling JW, Kemper AR, Kubik M, Landefeld CS, Mangione CM, Pbert L, Silverstein M, Simon MA, Tseng CW, Wong JB | title = Screening for Elevated Blood Lead Levels in Children and Pregnant Women: US Preventive Services Task Force Recommendation Statement | journal = JAMA | volume = 321 | issue = 15 | pages = 1502–1509 | date = April 2019 | pmid = 30990556 | doi = 10.1001/jama.2019.3326 | s2cid = 116860513 | doi-access = free }}</ref> The [[American College of Obstetricians and Gynecologists]] (ACOG) and [[American Academy of Pediatrics]] (AAP), however, recommend asking about risk factors and testing those who have them.<ref>{{cite journal |vauthors=Spanier AJ, McLaine P, Gilden RC |date=April 2019 |title=Screening for Elevated Blood Lead Levels in Children and Pregnant Women |url=https://jamanetwork.com/journals/jama/fullarticle/2730594 |url-status=live |journal=JAMA |volume=321 |issue=15 |pages=1464–1465 |doi=10.1001/jama.2019.2594 |pmid=30990534 |s2cid=205099056 |archive-url=https://web.archive.org/web/20190416191924/https://jamanetwork.com/journals/jama/fullarticle/2730594 |archive-date=16 April 2019|url-access=subscription }}</ref>

===Tertiary prevention===
Tertiary prevention methods focus on treatment, mitigation of symptoms, and improving quality of life in individuals who have already been affected by lead poisoning. These treatment methods are explored in the following section.<ref>{{cite journal |last1=Sample |first1=Jennifer |title=Lead Exposure in Children: Failure to Protect the Most Vulnerable |journal=J Pediatr Pharmacol Ther. |date=10 June 2024 |volume=29 |issue=3 |pages=212–214 |doi=10.5863/1551-6776-29.3.212 |pmid=38863859 |pmc=11163901 }}</ref>

==Treatment==
{| class="wikitable" style="float:right; margin-left:15px;"
|+ CDC management guidelines for children with elevated blood levels<ref name="Kosnett06-242">[[#CITEREFKosnett06Pois|Kosnett (2006)]] p. 242</ref>
! Blood lead<br /> level (μg/dL) !! Treatment
|-
! 10–14
| Education,<br /> repeat screening
|-
! 15–19
| Repeat screening, case<br /> management to abate sources
|-
! 20–44
| Medical evaluation,<br /> case management
|-
! 45–69
| Medical evaluation,<br /> chelation, case management
|-
! >69
| Hospitalization, immediate<br /> chelation, case management
|}

The mainstays of treatment are removal from the source of lead and, for people who have significantly high blood lead levels or who have symptoms of poisoning, [[chelation therapy]].<ref name="Henretig061321">[[#CITEREFHenretig06|Henretig (2006)]] p. 1321</ref> Treatment of iron, [[Hypocalcaemia|calcium]], and [[zinc deficiency|zinc deficiencies]], which are associated with increased lead absorption, is another part of treatment for lead poisoning.<ref name="Mycyk05-465">[[#CITEREFMycyk05|Mycyk, Hryhorczuk, Amitai (2005)]] p. 465</ref> When lead-containing materials are present in the gastrointestinal tract (as evidenced by abdominal X-rays), [[whole bowel irrigation]], [[Cathartic (medicine)|cathartic]]s, [[endoscopy]], or even surgical removal may be used to eliminate it from the gut and prevent further exposure.<ref name="Olson07">[[#CITEREFOlson07|Olson (2007)]] p. 1658</ref> Lead-containing bullets and shrapnel may also present a threat of further exposure and may need to be surgically removed if they are in or near fluid-filled or [[Synovial membrane|synovial]] spaces.<ref name="Kosnett06-241">[[#CITEREFKosnett06Pois|Kosnett (2006)]] p. 241</ref> If lead encephalopathy is present, [[anticonvulsant]]s may be given to control seizures, and treatments to control [[cerebral edema|swelling of the brain]] include [[corticosteroids]] and [[mannitol]].<ref name="Katzung07-948"/><ref name="Kosnett05-832">[[#CITEREFKosnett05|Kosnett (2005)]] p. 832</ref> Treatment of organic lead poisoning involves removing the lead compound from the skin, preventing further exposure, treating seizures, and possibly chelation therapy for people with high blood lead concentrations.<ref name="Katzung07-949">[[#CITEREFKatzung07|Kosnett (2007)]] p. 949</ref>

Before the advent of organic chelating agents, salts of [[iodide]] were given orally, such as heavily popularized by [[Louis Melsens]] and many nineteenth- and early twentieth-century doctors.<ref>[https://books.google.com/books?id=Cj9FAAAAcAAJ&pg=PP1 "Sur l'emploi de l'iodure de potassium pour combattre les affections saturnines et mercurielles"], in ''Annales de chimie et de physique'', t. 26, 3<sup>e</sup> série, 1849.</ref><ref name=KI_en>[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5192934/ "On the Employment of Iodide of Potassium as a Remedy for the Affections Caused by Lead and Mercury"], in ''Br Foreign Med Chir Rev.'' 1853 Jan; 11(21): 201–224.</ref>

<!--
CHELATION -->
[[File:Metal-EDTA.svg|thumb|left|EDTA, a [[Chelation|chelating agent]], binds a heavy metal, sequestering it.|alt=a chemical diagram of [CH2N(CH2CO2-)2]2 (shown in black) with the four O-tails binding a metal ion (shown in red).]]

<!--DEFINITION-->
A chelating agent is a molecule with at least two negatively charged groups that allow it to form complexes with metal ions with multiple positive charges, such as lead.<ref name="Trevor07-480">[[#CITEREFTrevor07|Trevor, Katzung, Masters (2007)]] p. 480</ref> The [[chelate]] that is thus formed is nontoxic<ref name="Lightfoot08-VetClin"/> and can be excreted in the urine, initially at up to 50 times the normal rate.<ref name="Kosnett05-822">[[#CITEREFKosnett05|Kosnett (2005)]] p. 822</ref> The chelating agents used for treatment of lead poisoning are edetate disodium calcium ([[Sodium calcium edetate|CaNa<sub>2</sub>EDTA]]), [[dimercaprol]] (BAL), which are injected, and [[Dimercaptosuccinic acid|succimer]] and d-[[penicillamine]], which are administered orally.<ref name="Menkes06">[[#CITEREFMenkes06|Menkes (2006)]] p.706</ref>
<!--
INDICATIONS
-->
[[Chelation therapy]] is used in cases of acute lead poisoning,<ref name="Patrick06">{{cite journal | vauthors = Patrick L | title = Lead toxicity, a review of the literature. Part 1: Exposure, evaluation, and treatment | journal = Alternative Medicine Review | volume = 11 | issue = 1 | pages = 2–22 | date = March 2006 | pmid = 16597190 }}</ref>{{ums|date=December 2017}} severe poisoning, and encephalopathy,<ref name="Olson07"/> and is considered for people with blood lead levels above 25&nbsp;μg/dL.<ref name="Brunton07-31"/> While the use of chelation for people with symptoms of lead poisoning is widely supported, use in asymptomatic people with high blood lead levels is more controversial.<ref name="Katzung07-948"/> Chelation therapy is of limited value for cases of chronic exposure to low levels of lead.<ref name="Meyer08-MutatRes">{{cite journal | vauthors = Meyer PA, Brown MJ, Falk H | title = Global approach to reducing lead exposure and poisoning | journal = Mutation Research | volume = 659 | issue = 1–2 | pages = 166–75 | year = 2008 | pmid = 18436472 | doi = 10.1016/j.mrrev.2008.03.003 | bibcode = 2008MRRMR.659..166M }}</ref> Chelation therapy is usually stopped when symptoms resolve or when blood lead levels return to premorbid levels.<ref name="Katzung07-948"/> When lead exposure has taken place over a long period, blood lead levels may rise after chelation is stopped because lead is leached into blood from stores in the bone;<ref name="Katzung07-948"/> thus, repeated treatments are often necessary.<ref name="Need2004" />

People receiving dimercaprol need to be assessed for peanut allergies since the commercial formulation contains peanut oil. Calcium EDTA is also effective if administered four hours after the administration of dimercaprol. Administering dimercaprol, DMSA (Succimer), or [[2,3-Dimercapto-1-propanesulfonic acid|DMPS]] before calcium EDTA is necessary to prevent the redistribution of lead into the central nervous system.<ref name=Flora2010>{{cite journal | vauthors = Flora SJ, Pachauri V | title = Chelation in metal intoxication | journal = International Journal of Environmental Research and Public Health | volume = 7 | issue = 7 | pages = 2745–88 | date = July 2010 | pmid = 20717537 | pmc = 2922724 | doi = 10.3390/ijerph7072745 | doi-access = free }}</ref> Dimercaprol used alone may also redistribute lead to the brain and testes.<ref name=Flora2010/> An adverse side effect of calcium EDTA is renal toxicity. Succimer (DMSA) is the preferred agent in mild to moderate lead poisoning cases. This may be the case in instances where children have a blood lead level >25&nbsp;μg/dL. The most reported adverse side effect for succimer is gastrointestinal disturbances.<ref name="Gra2007"/> It is also important to note that chelation therapy only lowers blood lead levels and may not prevent the lead-induced cognitive problems associated with lower lead levels in tissue. This may be because of the inability of these agents to remove sufficient amounts of lead from tissue or the inability to reverse preexisting damage.<ref name="Gra2007"/>
<!--
SIDE EFFECTS
-->
Chelating agents can have [[adverse medical effect|adverse effects]];<ref name="Brodkin07-CMAJ"/> for example, chelation therapy can lower the body's levels of necessary nutrients like zinc.<ref name="Lightfoot08-VetClin"/><ref>{{cite journal | vauthors = Bradberry S, Vale A | title = A comparison of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning | journal = Clinical Toxicology | volume = 47 | issue = 9 | pages = 841–58 | date = November 2009 | pmid = 19852620 | doi = 10.3109/15563650903321064 | s2cid = 29615354 }}</ref> Chelating agents taken orally can increase the body's absorption of lead through the intestine.<ref name="Pearson03-370"/>

<!--
CHELATION CHALLENGE
-->
Chelation challenge, also known as provocation testing, is used to indicate an elevated and mobilizable body burden of heavy metals including lead.<ref name="Brodkin07-CMAJ"/> This testing involves collecting urine before and after administering a one-off dose of chelating agent to mobilize heavy metals into the urine.<ref name="Brodkin07-CMAJ"/> Then urine is analyzed by a laboratory for levels of heavy metals; from this analysis overall body burden is inferred.<ref>{{cite journal | vauthors = Lee BK, Schwartz BS, Stewart W, Ahn KD | title = Provocative chelation with DMSA and EDTA: evidence for differential access to lead storage sites | journal = Occupational and Environmental Medicine | volume = 52 | issue = 1 | pages = 13–9 | date = January 1995 | pmid = 7697134 | pmc = 1128144 | doi = 10.1136/oem.52.1.13 }}</ref> Chelation challenge mainly measures the burden of lead in soft tissues, though whether it accurately reflects long-term exposure or the amount of lead stored in bone remains controversial.<ref name="who.int"/><ref name="Katzung07-948"/> Although the technique has been used to determine whether chelation therapy is indicated and to diagnose heavy metal exposure, some evidence does not support these uses as blood levels after chelation are not comparable to the reference range typically used to diagnose heavy metal poisoning.<ref name="Brodkin07-CMAJ"/> The single chelation dose could also redistribute the heavy metals to more sensitive areas such as central nervous system tissue.<ref name="Brodkin07-CMAJ"/>

==Epidemiology==
Since lead has been used widely for centuries, the effects of exposure are worldwide.<ref name="Payne08">{{cite journal | vauthors = Payne M | title = Lead in drinking water | journal = CMAJ | volume = 179 | issue = 3 | pages = 253–4 | date = July 2008 | pmid = 18663205 | pmc = 2474873 | doi = 10.1503/cmaj.071483 }}</ref> Environmental lead is ubiquitous, and everyone has some measurable blood lead level.<ref name="Karri08">{{cite journal | vauthors = Karri SK, Saper RB, Kales SN | title = Lead encephalopathy due to traditional medicines | journal = Current Drug Safety | volume = 3 | issue = 1 | pages = 54–9 | date = January 2008 | pmid = 18690981 | pmc = 2538609 | doi = 10.2174/157488608783333907 }}</ref><ref name="Hu07"/> Atmospheric lead pollution increased dramatically beginning in the 1950s as a result of the widespread use of leaded gasoline.<ref>{{cite web| url=http://www.unc.edu/courses/2006fall/envr/230/001/Needleman_2000.pdf| first = Herbert L. | last = Needleman | title=The Removal of Lead from Gasoline| publisher=University of North Carolina| date=June 28, 1999| url-status=live| archive-url=https://web.archive.org/web/20160303214833/http://www.unc.edu/courses/2006fall/envr/230/001/Needleman_2000.pdf| archive-date=March 3, 2016}}</ref> Lead is one of the largest [[environmental medicine]] problems in terms of numbers of people exposed and the public health toll it takes.<ref name="Pokras08-Ecohealth"/> Lead exposure accounts for about 0.2% of all deaths and 0.6% of [[disability adjusted life years]] globally.<ref>{{cite book|title=Global health risks: mortality and burden of disease attributable to selected major risks.|year=2009|publisher=World Health Organization|location=Geneva, Switzerland|isbn=978-92-4-156387-1|page=24|url=https://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_report_full.pdf|url-status=live|archive-url=https://web.archive.org/web/20120214111235/http://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_report_full.pdf|archive-date=2012-02-14}}</ref>

<!-- COUNTRY -->
Although regulation reducing lead in products has greatly reduced exposure in the developed world since the 1970s, lead is still allowed in products in many developing countries.<ref name="Pokras08-Ecohealth"/> According to the [[World Health Organization]], as of June 2022, only 45% of countries had confirmed legally-binding controls on production and use of lead paint.<ref>{{cite web |title=Legally-binding controls on lead paint |url=https://www.who.int/data/gho/data/themes/topics/indicator-groups/legally-binding-controls-on-lead-paint |access-date=2023-01-15 |website=www.who.int |language=en}}</ref> Significant disparities exist in the enactment of bans, with regions such as the [[Middle East]], [[North Africa]], and [[Sub-Saharan Africa]] currently the most likely to have countries lacking such measures. Despite a phase-out in many parts of the [[Global North]], Global South exposure has increased by nearly three times.<ref>{{cite book|last=Renfrew|first=Daniel|url=https://www.worldcat.org/oclc/1102765674|title=Life without lead: contamination, crisis, and hope in Uruguay|date=2019|isbn=978-0-520-96824-0|location=Oakland, California|pages=8|oclc=1102765674}}</ref> In all countries that have banned leaded gasoline, average blood lead levels have fallen sharply.<ref name="Meyer08-MutatRes"/> However, some developing countries still allow leaded gasoline,<ref name="Payne08"/> which is the primary source of lead exposure in most developing countries.<ref name="Meyer-IntJHyge"/> Beyond exposure from gasoline, the frequent use of pesticides in developing countries adds a risk of lead exposure and subsequent poisoning.<ref>{{cite journal | vauthors = Konradsen F, van der Hoek W, Cole DC, Hutchinson G, Daisley H, Singh S, Eddleston M | title = Reducing acute poisoning in developing countries--options for restricting the availability of pesticides | journal = Toxicology | volume = 192 | issue = 2–3 | pages = 249–61 | date = November 2003 | pmid = 14580791 | doi = 10.1016/S0300-483X(03)00339-1 | bibcode = 2003Toxgy.192..249K }}</ref><ref>{{cite web |date=2016-05-23 |title=THE PUBLIC HEALTH IMPACT OF CHEMICALS: KNOWNS AND UNKNOWNS |url=https://www.who.int/publications/i/item/WHO-FWC-PHE-EPE-16-01 |access-date=2023-01-15 |website=World Health Organization}}</ref> Poor children in developing countries are at especially high risk for lead poisoning.<ref name="Meyer-IntJHyge">{{cite journal | vauthors = Meyer PA, McGeehin MA, Falk H | title = A global approach to childhood lead poisoning prevention | journal = International Journal of Hygiene and Environmental Health | volume = 206 | issue = 4–5 | pages = 363–9 | date = August 2003 | pmid = 12971691 | doi = 10.1078/1438-4639-00232 | bibcode = 2003IJHEH.206..363M | url = https://zenodo.org/record/1236064 }}</ref> Of North American children, 7% have blood lead levels above 10&nbsp;μg/dL, whereas among Central and South American children, the percentage is 33–34%.<ref name="Payne08"/> About one fifth of the world's [[disease burden]] from lead poisoning occurs in the Western Pacific, and another fifth is in Southeast Asia.<ref name="Payne08"/>

<!-- RACE AND SES -->
In developed countries, people with low levels of education living in poorer areas are most at risk for elevated lead.<ref name="Pokras08-Ecohealth"/> In the US, the groups most at risk for lead exposure are the impoverished, city-dwellers, and immigrants.<ref name="Cleveland08">{{cite journal | vauthors = Cleveland LM, Minter ML, Cobb KA, Scott AA, German VF | title = Lead hazards for pregnant women and children: part 1: immigrants and the poor shoulder most of the burden of lead exposure in this country. Part 1 of a two-part article details how exposure happens, whom it affects, and the harm it can do | journal = The American Journal of Nursing | volume = 108 | issue = 10 | pages = 40–9; quiz 50 | date = October 2008 | pmid = 18827541 | doi = 10.1097/01.NAJ.0000337736.76730.66 }}</ref> African-American children and those living in old housing have also been found to be at elevated risk for high blood lead levels in the US.<ref name="Jones09">{{cite journal | vauthors = Jones RL, Homa DM, Meyer PA, Brody DJ, Caldwell KL, Pirkle JL, Brown MJ | title = Trends in blood lead levels and blood lead testing among US children aged 1 to 5 years, 1988-2004 | journal = Pediatrics | volume = 123 | issue = 3 | pages = e376-85 | date = March 2009 | pmid = 19254973 | doi = 10.1542/peds.2007-3608 | s2cid = 29464201 }}</ref> Low-income people often live in old housing with lead paint, which may begin to peel, exposing residents to high levels of lead-containing dust.

<!-- RISK FACTORS -->
Risk factors for elevated lead exposure include alcohol consumption and smoking (possibly because of contamination of tobacco leaves with lead-containing pesticides).<ref name="Hu07"/> Adults with certain risk factors might be more susceptible to toxicity; these include calcium and iron deficiencies, old age, disease of organs targeted by lead (e.g., the brain, the kidneys), and possibly genetic susceptibility.<ref name="Kosnett07EnvironHealthPers"/> <!--
SEX -->
Differences in vulnerability to lead-induced neurological damage between males and females have also been found, but some studies have found males to be at greater risk, while others have found females to be.<ref name="Bellinger04-Pedi"/>

<!-- AGE -->
In adults, blood lead levels steadily increase with increasing age.<ref name="Rossi09"/> In adults of all ages, men have higher blood lead levels than women do.<ref name="Rossi09"/> Children are more sensitive to elevated blood lead levels than adults are.<ref name="Murata">{{cite journal | vauthors = Murata K, Iwata T, Dakeishi M, Karita K | title = Lead toxicity: does the critical level of lead resulting in adverse effects differ between adults and children? | journal = Journal of Occupational Health | volume = 51 | issue = 1 | pages = 1–12 | year = 2009 | pmid = 18987427 | doi = 10.1539/joh.K8003 | s2cid = 27759109 | doi-access = free }}</ref> Children may also have a higher intake of lead than adults; they breathe faster and may be more likely to have contact with and ingest soil.<ref name="Dart041423"/> Children aged one to three tend to have the highest blood lead levels, possibly because at that age they begin to walk and explore their environment, and they use their mouths in their exploration.<ref name="Bellinger04-Pedi"/> Blood levels usually peak at about 18–24&nbsp;months old.<ref name="Pearson03"/> In many countries, including the US, household paint and dust are the major route of exposure in children.<ref name="Dart041423"/>

<gallery class="center" mode="packed" heights="170px">
Map showing the mean blood lead levels of overall adults in China during 1980–2018.jpg|Map showing the mean blood lead levels (BLLs) of adults in China during 1980–2018.
Trend of blood lead levels in Chinese adults in different regions from 1980 to 2018.jpg|Trend of blood lead levels (BLLs) in Chinese adults in different regions from 1980 to 2018. A decreasing trend was found in all regions except for South China.<ref>{{cite journal|url=https://www.sciencedirect.com/science/article/pii/S014765132100405X | title=Blood lead levels and their associated risk factors in Chinese adults from 1980 to 2018| year=2021| doi=10.1016/j.ecoenv.2021.112294| last1=Li| first1=Yanan| last2=Chen| first2=Jing| last3=Bu| first3=Shuhua| last4=Wang| first4=Shuo| last5=Geng| first5=Xue| last6=Guan| first6=Ge| last7=Zhao| first7=Qianwen| last8=Ao| first8=Lin| last9=Qu| first9=Weidong| last10=Zheng| first10=Yuxin| last11=Jin| first11=Yuan| last12=Tang| first12=Jinglong| journal=Ecotoxicology and Environmental Safety| volume=218| page=112294| pmid=33984660| bibcode=2021EcoES.21812294L| s2cid=234495451}}</ref>
</gallery>

===Notable cases===
{{Main|Lead poisoning epidemics}}
Cases of mass lead poisoning can occur. In 2009, 15,000 people were planned to be relocated from [[Jiyuan]] in central [[Henan province]] to other locations after 1000 children living around China's largest smelter plant (owned and operated by Yuguang Gold and Lead) were found to have excess lead in their blood. The total cost of this project is estimated to around 1&nbsp;billion yuan ($150&nbsp;million). 70% of the cost was estimated to be paid by the local government and the smelter company, while the rest would be paid by the residents themselves. The government suspended production at 32 of 35 lead plants.<ref name="China to relocate 15,000 from lead-poisoned area">{{cite news|url= https://news.yahoo.com/s/afp/20091016/hl_afp/healthchinaenvironmentpollutionlead |title=China to relocate 15,000 from lead-poisoned area |date=2009-10-16 |publisher=AFP|access-date=2009-10-20|archive-url= https://web.archive.org/web/20091019040748/http://news.yahoo.com/s/afp/20091016/hl_afp/healthchinaenvironmentpollutionlead <!--Added by H3llBot-->|archive-date=2009-10-19}}</ref> The affected area includes people from 10 different villages.<ref name="China to move residents from lead smelter base-report">{{cite news|url=https://www.reuters.com/article/rbssIndustryMaterialsUtilitiesNews/idUSPEK14546420091019|archive-url=https://web.archive.org/web/20180314104710/https://www.reuters.com/article/china-lead/china-to-move-residents-from-lead-smelter-base-report-idUSPEK14546420091019|archive-date=2018-03-14|title=China to move residents from lead smelter base-report|date=2009-10-18|work=Reuters|access-date=2009-10-20|url-status=live}}</ref>{{Update inline|date=January 2024}}

The [[Zamfara State lead poisoning epidemic]] occurred in Nigeria in 2010. As of 5 October 2010, at least 400 children have died from the effects of lead poisoning.<ref name="Aid groups say lead poisoning has killed 400 children in Nigeria">{{cite news |url= http://edition.cnn.com/2010/WORLD/africa/10/05/nigeria.lead.poisoning/|title=Aid groups say lead poisoning has killed 400 children in Nigeria |date=2010-10-05|agency=Associated Press|access-date=2010-10-05|url-status=live|archive-url= https://web.archive.org/web/20110805063306/http://edition.cnn.com/2010/WORLD/africa/10/05/nigeria.lead.poisoning/ |archive-date=2011-08-05}}</ref>

===Sex-specific susceptibility===
Neuroanatomical pathology due to lead exposure is more pronounced in males, suggesting that lead-related toxicity has a disparate impact across sexes.<ref name="Cecil08" />

==Prognosis==

===Reversibility===
The outcome is related to the extent and duration of lead exposure.<ref name="Chisolm04-223">[[#CITEREFChisolm04|Chisolm (2004)]] p. 223</ref> Effects of lead on the physiology of the kidneys and blood are generally reversible; its effects on the central nervous system are not.<ref name="Rubin08-267"/> While peripheral effects in adults often go away when lead exposure ceases, evidence suggests that most of lead's effects on a child's central nervous system are irreversible.<ref name="Bellinger04-Pedi">{{cite journal | vauthors = Bellinger DC | title = Lead | journal = Pediatrics | volume = 113 | issue = 4 Suppl | pages = 1016–22 | date = April 2004 | pmid = 15060194 | doi = 10.1542/peds.113.S3.1016 }}</ref> Children with lead poisoning may thus have adverse health, cognitive, and behavioral effects that follow them into adulthood.<ref name="Woolf07-PedClin">{{cite journal | vauthors = Woolf AD, Goldman R, Bellinger DC | title = Update on the clinical management of childhood lead poisoning | journal = Pediatric Clinics of North America | volume = 54 | issue = 2 | pages = 271–94, viii | date = April 2007 | pmid = 17448360 | doi = 10.1016/j.pcl.2007.01.008 }}</ref>

===Encephalopathy===
Lead encephalopathy is a medical emergency and causes permanent brain damage in 70–80% of children affected by it, even those that receive the best treatment.<ref name="Mycyk05-463"/> The mortality rate for people who develop cerebral involvement is about 25%, and of those who survive who had lead encephalopathy symptoms by the time chelation therapy was begun, about 40% have permanent neurological problems such as [[cerebral palsy]].<ref name="Brunton07-31">[[#CITEREFBrunton07|Brunton (2007)]] p. 1131</ref>

===Long-term===
Exposure to lead may also decrease lifespan and have health effects in the long term.<ref name="Need2004" /> [[Mortality rate|Death rates]] from a variety of causes are higher in people with elevated blood lead levels; these include cancer, stroke, heart disease, and general death rates from all causes.<ref name="Rossi09"/> Lead is considered a possible human [[carcinogen]] based on evidence from [[animal experimentation|animal studies]].<ref name="Merrill07862">[[#CITEREFMerrill07|Merrill, Morton, Soileau (2007)]] p. 862</ref> Evidence also suggests that age-related mental decline and psychiatric symptoms are correlated with lead exposure.<ref name="Hu07"/> Cumulative exposure over a prolonged period may have a more important effect on some aspects of health than recent exposure.<ref name="Hu07">{{cite journal | vauthors = Hu H, Shih R, Rothenberg S, Schwartz BS | title = The epidemiology of lead toxicity in adults: measuring dose and consideration of other methodologic issues | journal = Environmental Health Perspectives | volume = 115 | issue = 3 | pages = 455–62 | date = March 2007 | pmid = 17431499 | pmc = 1849918 | doi = 10.1289/ehp.9783 | bibcode = 2007EnvHP.115..455H }}</ref> Some health effects, such as [[high blood pressure]], are only significant risks when lead exposure is prolonged (over about one year).<ref name="Kosnett07EnvironHealthPers">{{cite journal | vauthors = Kosnett MJ, Wedeen RP, Rothenberg SJ, Hipkins KL, Materna BL, Schwartz BS, Hu H, Woolf A | title = Recommendations for medical management of adult lead exposure | journal = Environmental Health Perspectives | volume = 115 | issue = 3 | pages = 463–71 | date = March 2007 | pmid = 17431500 | pmc = 1849937 | doi = 10.1289/ehp.9784 | bibcode = 2007EnvHP.115..463K }}</ref> Furthermore, the neurological effects of lead exposure are exacerbated and long-lasting in low-income children in comparison to those of higher economic standing.<ref>{{cite journal|last1=Marshall|first1=Andrew T.|last2=Betts|first2=Samantha|last3=Kan|first3=Eric C.|last4=McConnell|first4=Rob|last5=Lanphear|first5=Bruce P.|last6=Sowell|first6=Elizabeth R.|date=January 2020|title=Association of lead-exposure risk and family income with childhood brain outcomes|journal=Nature Medicine|volume=26|issue=1|pages=91–97|doi=10.1038/s41591-019-0713-y|pmid=31932788|pmc=6980739|issn=1546-170X}}</ref> This does not imply that being wealthy can prevent lead from causing long-term mental health issues.<ref>{{cite journal |title=Childhood Lead Exposure May Affect Personality, Mental Health in Adulthood |last=Sancar |first=Feyza |date=March 27, 2019 |journal=JAMA |volume=321 |issue=15 |pages=1445–1446 |doi=10.1001/jama.2019.1116 |pmid=30916713 |s2cid=85530942 |quote=Associations between childhood BLL and adult personality and psychopathology remained significant even after adjusting for sex, maternal IQ, socioeconomic status, and family history of mental illness.|doi-access=free }}</ref>

== Violence ==
{{see also|Lead–crime hypothesis}}
Lead poisoning in children has been linked to changes in brain function that can result in low [[Intelligence quotient|IQ]] and increased impulsivity and aggression.<ref>{{cite journal|last=Sampson|first=R. J.|date=1992-12-01|title=A General Theory of Crime. By Michael R. Gottfredson and Travis Hirschi. Stanford University Press, 1990. 297 pp. Cloth $39.50; paper $12.95|url=http://dx.doi.org/10.1093/sf/71.2.545|journal=Social Forces|volume=71|issue=2|pages=545–546|doi=10.1093/sf/71.2.545|issn=0037-7732|url-access=subscription}}</ref> These traits of childhood lead exposure are associated with crimes of passion, such as aggravated assault in young adults.<ref>{{cite journal|last1=Carpenter|first1=David O.|last2=Nevin|first2=Rick|date=2010-02-09|title=Environmental causes of violence|url=http://www.sciencedirect.com/science/article/pii/S003193840900300X|journal=Physiology & Behavior|series=Conversations in the Discipline About Hormones- Part 1 of 2: The 50th Anniversary of the Discovery of the Estrogen Receptor.|volume=99|issue=2|pages=260–268|doi=10.1016/j.physbeh.2009.09.001|pmid=19758571|s2cid=5706643|issn=0031-9384|url-access=subscription}}</ref> An increase in lead exposure in children was linked to an increase in aggravated assault rates 22 years later.<ref name=":1">{{cite journal|last1=Mielke|first1=Howard W.|last2=Zahran|first2=Sammy|date=2012-08-01|title=The urban rise and fall of air lead (Pb) and the latent surge and retreat of societal violence|url=http://www.sciencedirect.com/science/article/pii/S0160412012000566|journal=Environment International|volume=43|pages=48–55|doi=10.1016/j.envint.2012.03.005|pmid=22484219|bibcode=2012EnInt..43...48M |issn=0160-4120|url-access=subscription}}</ref> For instance, the peak in [[leaded gasoline]] use in the late 1970s correlates with a peak in aggravated assault rates in the late 1990s in urban areas across the [[United States]].<ref name=":1" />

==History==
[[File:Dioscorides01.jpg|thumb|upright|[[Pedanius Dioscorides|Dioscorides]] noted lead's effect on the mind in the first century AD.|alt=an ancient Greek black-and-white woodcut print of a middle-aged bearded man. His left hand rests on a book, and in his right hand he holds a plant.]]
[[File:DSC00125 - Tubi di piombo romani - Foto di G. Dall'Orto.jpg|Roman lead water pipes with taps|thumb|right|alt=a block with two dull, dark gray metal spouts coming from the top. The spouts are chipped and very old-looking.]]
Lead poisoning was among the first known and most widely studied work-related [[environmental hazard]]s.<ref name="Flora08"/> One of the first metals to be [[smelting|smelted]] and used,<ref name="Henretig06"/> lead is thought to have been discovered and first [[mining|mine]]d in [[Anatolia]] around 6500 BC.<ref name="Gilbert06"/> Its density, workability, and corrosion resistance were among the metal's attractions.<ref name="Flora08"/>

<!-- GREEKS -->
In the 2nd century BC, the Greek botanist [[Nicander]] described the [[colic]] and [[paralysis]] seen in lead-poisoned people.<ref name="Pearce07-EurNeurol"/><ref name="Need2004" /> [[Pedanius Dioscorides|Dioscorides]], a Greek physician who lived in the 1st century AD, wrote that lead makes the mind "give way".<ref name="Henretig06"/><ref name="Needleman09-AnnEP">{{cite journal | vauthors = Needleman H | title = Low level lead exposure: history and discovery | journal = Annals of Epidemiology | volume = 19 | issue = 4 | pages = 235–8 | date = April 2009 | pmid = 19344860 | doi = 10.1016/j.annepidem.2009.01.022 }}</ref>

<!--ROMANS -->
Lead was used extensively in [[Roman aqueduct]]s from about 500&nbsp;BC to 300&nbsp;AD.<ref name="Gilbert06"/> [[Julius Caesar]]'s engineer, [[Vitruvius]], reported, "water is much more wholesome from [[earthenware]] pipes than from lead pipes. For it seems to be made injurious by lead, because [[white lead]] is produced by it, and this is said to be harmful to the human body."<ref name="Prioreschi98">{{cite book |title= A History of Medicine, Volume 3 Of Roman Medicine | vauthors = Prioreschi P |year=1998 |publisher= Horatius Press |isbn= 978-1-888456-03-5 |page=279}}</ref> [[Gout]], prevalent in affluent Rome, is thought to be the result of lead, or leaded eating and drinking vessels. Sugar of lead ([[lead(II) acetate]]) was used to sweeten wine, and the gout that resulted from this was known as "saturnine" gout.<ref>{{cite journal | vauthors = Couper RT | title = The severe gout of Emperor Charles V | journal = The New England Journal of Medicine | volume = 355 | issue = 18 | pages = 1935–6; author reply 1936 | date = November 2006 | pmid = 17079773 | doi = 10.1056/NEJMc062352 }}</ref> It is even [[Roman lead poisoning theory|hypothesized that lead poisoning]] may have contributed to the [[decline of the Roman Empire]],<ref name="Need2004" /><ref name="Henretig06"/> a hypothesis thoroughly disputed:

{{blockquote|The great disadvantage of lead has always been that it is poisonous. This was fully recognised by the ancients, and Vitruvius specifically warns against its use. Because it was nevertheless used in profusion for carrying drinking water, the conclusion has often been drawn that the Romans must therefore have suffered from lead poisoning; sometimes conclusions are carried even further and it is inferred that this caused infertility and other unwelcome conditions, and that lead plumbing was largely responsible for the decline and fall of Rome.

Two things make this otherwise attractive hypothesis impossible. First, the [[calcium carbonate]] deposit that formed so thickly inside the [[aqueduct (watercourse)|aqueduct]] channels also formed inside the pipes, effectively insulating the water from the lead, so that the two never touched. Second, because the Romans had so few [[faucet|taps]] and the water was constantly running, it was never inside the pipes for more than a few minutes, and certainly not long enough to become contaminated.<ref>{{harvnb|Hodge|1992|p=308}}</ref>}}

However, recent research supports the idea that the lead found in the water came from the supply pipes, rather than another source of contamination. It was not unknown for locals to punch holes in the pipes to draw water off, increasing the number of people exposed to the lead.

Romans also consumed lead through the consumption of [[defrutum|''defrutum'', ''carenum'', and ''sapa'']], [[must]]s made by boiling down fruit in lead cookware. {{Lang|la|Defrutum}} and its relatives were used in [[ancient Roman cuisine]] and cosmetics, including as a [[food preservative]].<ref name="Brighton">{{cite video |title=Tales of the Living Dead: Poisoned Roman Babies |date=2004 |medium=television |publisher=Brighton TV for National Geographic |people=Director: Chris Warren}}</ref> The use of leaden cookware, though popular, was not the general standard and copper cookware was used far more generally. There is also no indication how often {{Lang|la|sapa}} was added or in what quantity.

In 1983, environmental chemist [[Jerome Nriagu]] argued in a milestone paper that Roman civilization collapsed as a result of lead poisoning.<ref name="pmid6338384">{{cite journal |vauthors=Nriagu JO |date=March 1983 |title=Saturnine gout among Roman aristocrats. Did lead poisoning contribute to the fall of the Empire? |journal=The New England Journal of Medicine |volume=308 |issue=11 |pages=660–3 |doi=10.1056/NEJM198303173081123 |pmid=6338384}}</ref> [[Clair Patterson]], the scientist who convinced governments to ban lead from gasoline, enthusiastically endorsed this idea, which nevertheless triggered a volley of publications aimed at refuting it.{{Citation needed|reason=Where does Patterson endorse Nriagu?|date=February 2025}} In 1984, John Scarborough, a pharmacologist and classicist, criticized the conclusions drawn by Nriagu's book as "so full of false evidence, miscitations, typographical errors, and a blatant flippancy regarding primary sources that the reader cannot trust the basic arguments."<ref name="pmid6389691">{{cite journal |vauthors=Scarborough J |date=October 1984 |title=The Myth of Lead Poisoning Among the Romans: An Essay Review |journal=Journal of the History of Medicine and Allied Sciences |volume=39 |issue=4 |pages=469–75 |doi=10.1093/jhmas/39.4.469 |pmid=6389691}}</ref> Although today lead is no longer seen as the prime culprit of Rome's demise, its status in the system of water distribution by lead pipes ({{Lang|la|fistulæ}}) still stands as a major public health issue. By measuring Pb isotope compositions of sediments from the Tiber River and the Trajanic Harbor, the present work shows that "tap water" from ancient Rome had 100 times more lead than local spring waters.<ref>{{cite journal | vauthors = Delile H, Blichert-Toft J, Goiran JP, Keay S, Albarède F | title = Lead in ancient Rome's city waters | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 111 | issue = 18 | pages = 6594–9 | date = May 2014 | pmid = 24753588 | pmc = 4020092 | doi = 10.1073/pnas.1400097111 | bibcode = 2014PNAS..111.6594D | doi-access = free }}</ref><ref>{{cite web | url = https://www.theguardian.com/science/2014/apr/21/ancient-rome-tap-water-contaminated-lead-researchers | title = Ancient Rome's tap water heavily contaminated with lead, researchers say | archive-url = https://web.archive.org/web/20170227163345/https://www.theguardian.com/science/2014/apr/21/ancient-rome-tap-water-contaminated-lead-researchers | archive-date=2017-02-27 | work = The Guardian | date = 21 April 2014 }}</ref><ref>{{cite web | first =  Gemma | last = Tarlach | url = http://blogs.discovermagazine.com/d-brief/2014/04/21/ancient-romes-water-100-times-lead-local-spring-water/ | title = Lead in Ancient Rome's Water Was 100 Times Natural Levels | archive-url = https://web.archive.org/web/20160114092050/http://blogs.discovermagazine.com/d-brief/2014/04/21/ancient-romes-water-100-times-lead-local-spring-water/ | archive-date=2016-01-14 | work = Discover | date = 21 April 2014 }}</ref>

A study published in January 2025 concluded that lead pollution peaked during a prosperous period known as the Pax Romana, adding credence to the theory that lead pollution have contributed to the decline of the Roman Empire.<ref>{{Cite journal |last1=McConnell |first1=Joseph R. |last2=Chellman |first2=Nathan J. |last3=Plach |first3=Andreas |last4=Wensman |first4=Sophia M. |last5=Plunkett |first5=Gill |last6=Stohl |first6=Andreas |last7=Smith |first7=Nicole-Kristine |last8=Møllesøe Vinther |first8=Bo |last9=Dahl-Jensen |first9=Dorthe |last10=Steffensen |first10=Jørgen Peder |last11=Fritzsche |first11=Diedrich |last12=Camara-Brugger |first12=Sandra O. |last13=McDonald |first13=Brandon T. |last14=Wilson |first14=Andrew I. |date=2025-01-21 |title=Pan-European atmospheric lead pollution, enhanced blood lead levels, and cognitive decline from Roman-era mining and smelting |journal=Proceedings of the National Academy of Sciences |language=en |volume=122 |issue=3 |doi=10.1073/pnas.2419630121 |issn=0027-8424 |pmc=11760502 |pmid=39761387|bibcode=2025PNAS..12219630M }}</ref>

<!-- 16TH, 17TH, 18TH CENTURIES -->
After [[Classical Antiquity|antiquity]], mention of lead poisoning was absent from [[medical literature]] until the end of the [[Middle Ages]].<ref name="Hernberg00">{{cite journal | vauthors = Hernberg S | title = Lead poisoning in a historical perspective | journal = American Journal of Industrial Medicine | volume = 38 | issue = 3 | pages = 244–54 | date = September 2000 | pmid = 10940962 | doi = 10.1002/1097-0274(200009)38:3<244::AID-AJIM3>3.0.CO;2-F }}</ref> In 1656 the German physician [[Samuel Stockhausen]] recognized dust and fumes containing lead compounds as the cause of disease, called since ancient Roman times {{Lang|la|morbi metallici}}, that were known to afflict miners, smelter workers, [[pottery|potters]], and others whose work exposed them to the metal.<ref name="Eisinger-colic" /><ref name="Gochfeld-history">{{cite journal | vauthors = Gochfeld M | title = Chronologic history of occupational medicine | journal = Journal of Occupational and Environmental Medicine | volume = 47 | issue = 2 | pages = 96–114 | date = February 2005 | pmid = 15706170 | doi = 10.1097/01.jom.0000152917.03649.0e | s2cid = 35548035 }}</ref>

The painter [[Caravaggio]] might have died of lead poisoning. Bones with high lead levels were recently found in a grave thought likely to be his.<ref>{{cite web | first = Tom | last = Kington | url = https://www.theguardian.com/artanddesign/2010/jun/16/caravaggio-italy-remains-ravenna-art | title = The mystery of Caravaggio's death solved at last – painting killed him | archive-url = https://web.archive.org/web/20130825140508/http://www.theguardian.com/artanddesign/2010/jun/16/caravaggio-italy-remains-ravenna-art | archive-date=2013-08-25 | work = The Guardian | date = 16 June 2010 }}</ref> Paints used at the time contained high amounts of lead salts. Caravaggio is known to have exhibited violent behavior, a symptom commonly associated with lead poisoning.

In 17th-century Germany, the physician [[Eberhard Gockel]] discovered lead-contaminated wine to be the cause of an epidemic of [[colic]].<ref name="Eisinger-colic" /> He had noticed that monks who did not drink wine were healthy, while wine drinkers developed colic,<ref name="Pearce07-EurNeurol"/> and traced the cause to sugar of lead, made by simmering [[litharge]] with vinegar.<ref name="Eisinger-colic" /> As a result, [[Eberhard Ludwig, Duke of Württemberg]] issued an [[edict]] in 1696 banning the adulteration of wines with litharge.<ref name="Eisinger-colic">{{cite journal | vauthors = Eisinger J | title = Lead and wine. Eberhard Gockel and the colica Pictonum | journal = Medical History | volume = 26 | issue = 3 | pages = 279–302 | date = July 1982 | pmid = 6750289 | pmc = 1139187 | doi = 10.1017/s0025727300041508 }}</ref>

In the 18th century lead poisoning was fairly frequent on account of the widespread drinking of [[rum]], which was made in [[still]]s with a lead component (the "worm"). It was a significant cause of mortality amongst slaves and sailors in the colonial West Indies.<ref>{{cite journal|journal=Caribbean Connection|title=A Preliminary Investigation of Lead Poisoning in a Napoleonic Era Naval Cemetery in Antigua, W.I.|volume=2|date=October 2012| last1 = Varney | first1 = Tamara L | last2 = Murphy | first2 = A. Reginald |url=http://journal.fieldresearchcentre.org/Varney,%20et%20al.pdf |archive-url=https://web.archive.org/web/20211122101900/http://journal.fieldresearchcentre.org/Varney,%20et%20al.pdf |url-status=dead |archive-date=November 22, 2021 |display-authors=etal}}</ref><ref>{{cite book|title=Death by Migration: Europe's Encounter with the Tropical World in the Nineteenth Century| last = Curtin | first = Philip D. |date=November 1989|isbn=978-0-521-38922-8|pages=78–79| publisher = Cambridge University Press }}</ref> Lead poisoning from rum was also noted in [[Boston, Massachusetts|Boston]].<ref>{{cite book | vauthors = Brands HW |author-link=H. W. Brands |title=The First American: The Life and Times of Benjamin Franklin |location=New York |publisher=Anchor Books |year=2000 |isbn=978-0-385-49540-0}}</ref> [[Benjamin Franklin]] suspected lead to be a risk in 1786.<ref>{{cite web | work = The Franklin Institute | date = 2010 | url = http://www.fi.edu/learn/brain/metals.html | title = Benjamin Franklin's Lead Letter, History's Lead Story | archive-url = https://web.archive.org/web/20140409224551/http://www.fi.edu/learn/brain/metals.html | archive-date = 2014-04-09 }}</ref> Also in the 18th century, "[[Devonshire colic]]" was the name given to the symptoms experienced by people of [[Devon]] who drank cider made in [[fruit press|press]]es that were lined with lead.<ref name="Pearce07-EurNeurol"/> Lead was added to cheap wine illegally in the 18th and early 19th centuries as a sweetener.<ref name="Mai06-JRColl"/> The composer [[Ludwig van Beethoven|Beethoven]], a heavy wine drinker, had elevated lead levels (as later detected in his [[human hair|hair]]) possibly due to this; lead poisoning is a contender as a factor to his [[hearing loss]] and death (cause of which is still controversial).<ref name="Mai06-JRColl">{{cite journal | vauthors = Mai FM | title = Beethoven's terminal illness and death | journal = The Journal of the Royal College of Physicians of Edinburgh | volume = 36 | issue = 3 | pages = 258–63 | date = October 2006 | doi = 10.1177/1478271520063603021 | pmid = 17214130 }}</ref><ref>{{cite news | last = Weiss | first = Rick | url = https://www.washingtonpost.com/wp-dyn/content/article/2005/12/05/AR2005120501937.html | title = Study Concludes Beethoven Died From Lead Poisoning | archive-url =  https://web.archive.org/web/20170215071732/http://www.washingtonpost.com/wp-dyn/content/article/2005/12/05/AR2005120501937.html | archive-date=2017-02-15 | newspaper = The Washington Post | date = December 6, 2005 }}</ref><ref>{{Cite news |last=Kolata |first=Gina |date=2024-05-06 |title=Locks of Beethoven's Hair Offer New Clues to the Mystery of His Deafness |url=https://www.nytimes.com/2024/05/06/health/beethoven-deaf-lead-hair.html |url-status=live |archive-url=https://web.archive.org/web/20240506213229/https://www.nytimes.com/2024/05/06/health/beethoven-deaf-lead-hair.html |archive-date=2024-05-06 |access-date=2024-06-15 |work=The New York Times |language=en-US |issn=0362-4331}}</ref>

<!-- 19TH AND 20TH CENTURIES -->
With the [[Industrial Revolution]] in the 19th century, lead poisoning became common in the work setting.<ref name="Henretig06"/> The introduction of lead paint for residential use in the 19th century increased childhood exposure to lead; for millennia before this, most lead exposure had been [[occupational disease|occupational]].<ref name="Bellinger04-Pedi"/> The first legislation in the UK to limit pottery workers' exposure to lead was included in the [[Factory Acts#Factories Act Extension Act 1867|Factories Act Extension Act in 1864]], with further introduced in 1899.<ref>{{cite web |url=http://www.stokemuseums.org.uk/collections/browse_collections/ceramics/research_resources/general/health_risks_pottery |title=Stoke Museums - Health Risks in a Victorian Pottery Industry |date=7 July 2012 |website=Stoke Museums |access-date=23 February 2022 |archive-url=https://web.archive.org/web/20120707001548/http://www.stokemuseums.org.uk/collections/browse_collections/ceramics/research_resources/general/health_risks_pottery |archive-date=7 July 2012 |url-status=dead}}</ref><ref>{{cite web | url=https://www.historyofosh.org.uk/timeline.html | title=Timeline - History of Occupational Safety and Health }}</ref> [[William James Furnival]] (1853–1928), research ceramist of City & Guilds London Institute, appeared before Parliament in 1901 and presented a decade's evidence to convince the nation's leaders to remove lead completely from the British ceramic industry. His 852-page treatise, ''Leadless Decorative Tiles, Faience, and Mosaic'' of 1904, published that campaign and provided recipes to promote lead-free ceramics.<ref>{{cite book|last=Furnival|first= William James|title=Leadless Decorative Tiles, Faience, and Mosaic, comprising notes and receipts on the History, Materials, Manufacture & Use of Ornamental Flooring Tiles, Ceramic Mosaic, and Decorative Tiles and Faience| publisher=W.J. Furival, Stone, Staffordshire|year=1904}}</ref> At the request of the Illinois state government in the US, [[Alice Hamilton]] (1869–1970) documented lead toxicity in Illinois industry and in 1911 presented results to the 23rd Annual Meeting of the American Economic Association.<ref>{{cite journal|journal=The American Economic Review|title = Lead Poisoning in Illinois|volume = 1| number=2|date = April 1911| pages = 257–264 | last= Hamilton| first= Alice}}</ref> Hamilton was a founder of the field of [[occupational safety and health]] and published the first edition of her manual, ''Industrial Toxicology'', in 1934, yet in print in revised forms.<ref>{{cite book|last=Hamilton|first= Dr. Alice|title=Industrial Toxicology|publisher=University of Michigan|year=1934}}</ref> An important step in the understanding of childhood lead poisoning occurred when [[toxicity]] in children from lead paint was recognized in Australia in 1897.<ref name="Henretig06"/> France, Belgium, and Austria banned white lead interior paints in 1909; the [[League of Nations]] followed suit in 1922.<ref name="Gilbert06"/> However, in the United States, laws banning lead house paint were not passed until 1971, and it was phased out and not fully banned until 1978.<ref name="Gilbert06"/>

The 20th century saw an increase in worldwide lead exposure levels due to the increased widespread use of the metal.<ref name="Grant09-757">[[#CITEREFGrant09|Grant (2009)]] p. 757</ref> Beginning in the 1920s, [[Gasoline#Tetraethyl lead|lead was added to gasoline]] to improve its [[combustion]]; lead from this [[exhaust gas|exhaust]] persists today in soil and dust in buildings.<ref name="Rossi09"/> Midcentury ceramicist [[Carol Janeway]] provides a case history of lead poisoning in an artist using lead glazes in decorating tiles in the 1940s; her monograph suggests that other artists' potential for lead poisoning be investigated, for example [[Vally Wieselthier]] and [[Dora Carrington]].<ref>{{cite book|last=Jenssen| first=Victoria|title= The Art of Carol Janeway| chapter= ''Ch.16 Unsafe Studio Practice; Lead Poisoning''|publisher=Friesen Press |year=2022|pages=198–206}}</ref> Blood lead levels worldwide have been declining sharply since the 1980s, when leaded gasoline began to be phased out.<ref name="Rossi09"/> In those countries that have banned lead in [[solder]] for food and drink cans and have banned leaded [[gasoline additive]]s, blood lead levels have fallen sharply since the mid-1980s.<ref name="Mycyk05-467">[[#CITEREFMycyk05|Mycyk, Hryhorczuk, Amitai (2005)]] p. 467</ref>

The levels found today in most people are orders of magnitude greater than those of [[pre-industrial society]].<ref name="Merrill07861">[[#CITEREFMerrill07|Merrill, Morton, Soileau (2007)]] p. 861</ref> Due to reductions of lead in products and the workplace, acute lead poisoning is rare in most countries today, but low-level lead exposure is still common.<ref name="Chiras09">{{cite book |title= Environmental Science |edition= 8th | vauthors = Chiras DD |year= 2009 |publisher= Jones & Bartlett |isbn= 978-0-7637-5925-4 |page= [https://archive.org/details/environmentalsci8thechir/page/394 394] |url= https://archive.org/details/environmentalsci8thechir/page/394 }}</ref><ref>{{cite journal|last1=Ericson|first1=Bret|last2=Hu|first2=Howard|last3=Nash|first3=Emily|last4=Ferraro|first4=Greg|last5=Sinitsky|first5=Julia|last6=Taylor|first6=Mark Patrick|date=2021-03-01|title=Blood lead levels in low-income and middle-income countries: a systematic review|journal=The Lancet Planetary Health|language=English|volume=5|issue=3|pages=e145–e153|doi=10.1016/S2542-5196(20)30278-3|issn=2542-5196|pmid=33713615|s2cid=232222146|doi-access=free}}{{Dead link|date=July 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> It was not until the second half of the 20th century that [[subclinical]] lead exposure became understood to be a problem.<ref name="Hernberg00"/> During the end of the 20th century, the blood lead levels deemed acceptable steadily declined.<ref name="Grant09-758">[[#CITEREFGrant09|Grant (2009)]] p. 758</ref> Blood lead levels once considered safe are now considered hazardous, with no known safe threshold.<ref name="Sanborn"/><ref>{{cite web |author=Agency for Toxic Substances and Disease Registry |url=https://www.atsdr.cdc.gov/csem/csem.html |title=Lead Toxicity Cover Page |work=Environmental Health and Medicine Education |publisher=U.S. Department of Health and Human Services |id=Course: WB 1105 |date=August 20, 2007 |url-status=live |archive-url=https://archive.today/20120718161039/http://www.atsdr.cdc.gov/csem/csem.asp?csem=7&po=0 |archive-date=July 18, 2012 }}</ref>

In the late 1950s through the 1970s [[Herbert Needleman]] and [[Clair Patterson|Clair Cameron Patterson]] did research trying to prove lead's toxicity to humans.<ref>{{cite book |last=Denworth |first=Lydia |title=Toxic Truth: a scientist, a Doctor, and the battle over Lead |publisher=Beacon Press |page=[https://archive.org/details/toxictruthscient00denw_0/page/210 210] |isbn=978-0-8070-0032-8 |year=2008 |url-access=registration |url=https://archive.org/details/toxictruthscient00denw_0/page/210 }}</ref> In the 1980s Needleman was falsely accused of scientific misconduct by lead industry associates.<ref>{{cite book |last=Kennedy |first=Donald |date=1997 |title=Academic Duty |url=https://archive.org/details/academicduty00dona |url-access=registration |publisher=Harvard University Press |page=[https://archive.org/details/academicduty00dona/page/237 237] |isbn=978-0-674-00222-7 }}</ref><ref>{{cite journal | vauthors = Needleman H | title = Standing up to the lead industry: an interview with Herbert Needleman. Interview by David Rosner and Gerald Markowitz | journal = Public Health Reports | volume = 120 | issue = 3 | pages = 330–7 | date = May–June 2005 | pmid = 16134577 | pmc = 1497712 | doi = 10.1177/003335490512000319 | url = http://www.publichealthreports.org/issueopen.cfm?articleID=1479 | url-status = live | archive-date = 3 September 2014 | archive-url = https://web.archive.org/web/20140903191927/http://www.publichealthreports.org/issueopen.cfm?articleID=1479 | author-link1 = David Rosner }}</ref>

In 2002 [[Tommy Thompson]], United States Secretary of Health and Human Services, appointed at least two persons with [[Conflict of interest|conflicts of interest]] to the CDC's Lead Advisory Committee.<ref>{{cite web |url=http://www.ucsusa.org/scientific_integrity/abuses_of_science/lead-poisoning-prevention.html |title=Lead Poisoning Prevention Panel Influenced by Industry |author=<!--Staff writer(s); no by-line.--> |date=8 February 2004 |website=The Center for Science and Democracy |publisher=Union of Concerned Scientists |access-date=8 October 2002 |url-status=live |archive-url=https://web.archive.org/web/20081025233131/http://www.ucsusa.org/scientific_integrity/abuses_of_science/lead-poisoning-prevention.html |archive-date=25 October 2008 }}</ref><ref>{{cite web |url=http://www.house.gov/markey/iss_environment_rpt021008.pdf |title=Turning Lead Into Gold: How the Bush Administration is Poisoning the Lead Advisory Committee at the CDC |last1=Markey |first1=Edward J. |date=8 October 2002 |website=US House of Representatives |access-date=28 August 2014| url-status=dead | archive-url=https://web.archive.org/web/20021024155813/http://www.house.gov/markey/iss_environment_rpt021008.pdf |archive-date=24 October 2002}}</ref>

In 2014, a case by the State of California against several companies decided against [[Sherwin-Williams]], [[NL Industries]], and [[ConAgra]] and ordered them to pay $1.15 billion.<ref>{{cite web|vauthors=Hsiao H, Stanley A|title=Lead Paint Companies Hit With Billion Dollar Judgment in California Public Nuisance Case|url=https://media2.mofo.com/documents/140113-lead-paint.pdf|access-date=21 August 2016|archive-date=1 December 2017|archive-url=https://web.archive.org/web/20171201041416/https://media2.mofo.com/documents/140113-lead-paint.pdf|url-status=dead}}</ref> The disposition of ''The People v. ConAgra Grocery Products Company et al.'' in the California 6th Appellate District Court on 14 November 2017 is that:{{blockquote|... the judgment is reversed, and the matter is remanded to the trial court with directions to (1) recalculate the amount of the abatement fund to limit it to the amount necessary to cover the cost of remediating pre-1951 homes, and (2) hold an evidentiary hearing regarding the appointment of a suitable receiver. The Plaintiff shall recover its costs on appeal.<ref name=PeopleVsConagra>{{cite web |url=http://appellatecases.courtinfo.ca.gov/search/case/dockets.cfm?doc_id=2073589&doc_no=H040880&dist=6 |title=The People v. ConAgra Grocery Products Company et al. | vauthors  = Mihara ND, Premo EM, Elia FD |date=2017-11-14 |website=California Courts - Appellate Court Case Information |publisher=Judicial Council of California |access-date=2017-11-19 |quote=...we can accept the inference that defendants' pre-1951 promotions increased the use of lead paint on residential interiors during the period of those promotions...}}</ref>}}

On 6 December 2017, the petitions for rehearing from NL Industries, Inc., ConAgra Grocery Products Company, and The Sherwin-Williams Company were denied.<ref name=PeopleVsConagra />

Studies have found a weak link between lead from leaded gasoline and crime rates.<ref>{{cite journal | vauthors = Hall W | title = Did the elimination of lead from petrol reduce crime in the USA in the 1990s? | journal = F1000Research | volume = 2 | page = 156 | date = 2013 | pmid = 24555074 | pmc = 3829390 | doi = 10.12688/f1000research.2-156.v2 | doi-access = free }}</ref>

{{as of|2022}} in the United States, lead paint in rental housing remains a hazard to children. Both landlords and insurance companies have adopted strategies that limit the chance of recovery for damages due to lead poisoning: insurance companies by excluding coverage for lead poisoning from policies, and landlords by crafting barriers to the collection of any monetary damages compensating plaintiffs for damage.<ref name="NYT32922">{{cite news |author1=Ellen Gabler |title=How 2 Industries Stymied Justice for Young Lead Paint Victims |url=https://www.nytimes.com/2022/03/29/us/lead-poisoning-insurance-landlords.html |access-date=March 29, 2022 |work=The New York Times |date=March 29, 2022}}</ref>

==Other species==
{{Main|Animal lead poisoning}}
Humans are not alone in suffering from lead's effects; plants and animals are also affected by lead toxicity to varying degrees depending on species.<ref name="Yu05-188"/> Animals experience many of the same effects of lead exposure as humans do, such as abdominal pain, peripheral [[neuropathy]], and behavioral changes such as increased aggression.<ref name="Pokras08-Ecohealth"/> Much of what is known about human lead toxicity and its effects is derived from animal studies.<ref name="Bellinger04-Pedi"/> Animals are used to test the effects of treatments, such as chelating agents,<ref name="Redig08">{{cite journal | vauthors = Redig PT, Arent LR | title = Raptor toxicology | journal = The Veterinary Clinics of North America. Exotic Animal Practice | volume = 11 | issue = 2 | pages = 261–82, vi | date = May 2008 | pmid = 18406387 | doi = 10.1016/j.cvex.2007.12.004 }}</ref> and to provide information on the pathophysiology of lead, such as how it is absorbed and distributed in the body.<ref name="Grant09-768-71">[[#CITEREFGrant09|Grant (2009)]] pp. 768, 771, 774</ref>

Farm animals such as cows and horses<ref name="Neathery">{{cite journal | vauthors = Neathery MW, Miller WJ | title = Metabolism and toxicity of cadmium, mercury, and lead in animals: a review | journal = Journal of Dairy Science | volume = 58 | issue = 12 | pages = 1767–81 | date = December 1975 | pmid = 1107364 | doi = 10.3168/jds.S0022-0302(75)84785-0 | doi-access = free }}</ref> as well as pet animals are also susceptible to the effects of lead toxicity.<ref name="Lightfoot08-VetClin"/> Sources of lead exposure in pets can be the same as those that present health threats to humans sharing the environment, such as paint and blinds, and there is sometimes lead in toys made for pets.<ref name="Lightfoot08-VetClin"/> Lead poisoning in a pet dog may indicate that children in the same household are at increased risk for elevated lead levels.<ref name="Pokras08-Ecohealth"/>

===Wildlife===
[[File:Condor de Calofornie.jpg|thumb|right|[[Turkey vultures]] (''Cathartes aura'', shown), and [[California condor]]s can be poisoned when they eat carcasses of animals shot with lead pellets.|alt=A large tan bird of prey with dark brown neck feathers and a bare red head sits on a dead cow in a desert with dead grass and scrub]]
Lead, one of the leading causes of toxicity in waterfowl, has been known to cause die-offs of wild bird populations.<ref name="Lightfoot08-VetClin">{{cite journal | vauthors = Lightfoot TL, Yeager JM | title = Pet bird toxicity and related environmental concerns | journal = The Veterinary Clinics of North America. Exotic Animal Practice | volume = 11 | issue = 2 | pages = 229–59, vi | date = May 2008 | pmid = 18406386 | doi = 10.1016/j.cvex.2008.01.006 }}</ref> When hunters use [[lead shot]], [[waterfowl]] such as ducks can ingest the spent pellets later and be poisoned; predators that eat these birds are also at risk.<ref name="Ferreyra09">{{cite journal | vauthors = Ferreyra H, Romano M, Uhart M | title = Recent and chronic exposure of wild ducks to lead in human-modified wetlands in Santa Fe Province, Argentina | journal = Journal of Wildlife Diseases | volume = 45 | issue = 3 | pages = 823–7 | date = July 2009 | pmid = 19617495 | doi = 10.7589/0090-3558-45.3.823 | s2cid = 9693691 | doi-access = free }}</ref> Lead shot-related waterfowl poisonings were first documented in the US in the 1880s.<ref name="Pokras08-Ecohealth"/> By 1919, the spent lead pellets from waterfowl hunting was positively identified as the source of waterfowl deaths.<ref name="FedCartridge">Federal Cartridge Company Waterfowl and Steel Shot Guide. Volume I; 1988.</ref> Lead shot has been banned for hunting waterfowl in several countries,<ref name="Pokras08-Ecohealth">{{cite journal | vauthors = Pokras MA, Kneeland MR | title = Lead poisoning: using transdisciplinary approaches to solve an ancient problem | journal = EcoHealth | volume = 5 | issue = 3 | pages = 379–85 | date = September 2008 | pmid = 19165554 | doi = 10.1007/s10393-008-0177-x | s2cid = 21280606 }}</ref> including the US in 1991 and Canada in 1997.<ref name="Degernes08-VetClin">{{cite journal | vauthors = Degernes LA | title = Waterfowl toxicology: a review | journal = The Veterinary Clinics of North America. Exotic Animal Practice | volume = 11 | issue = 2 | pages = 283–300, vi | date = May 2008 | pmid = 18406388 | doi = 10.1016/j.cvex.2007.12.001 }}</ref> Other threats to wildlife include lead paint, sediment from lead mines and smelters, and lead weights from fishing lines.<ref name="Degernes08-VetClin"/> Lead in some fishing gear has been banned in several countries.<ref name="Pokras08-Ecohealth"/>

The [[Critically endangered species|critically endangered]] [[California condor]] has also been affected by lead poisoning. As [[scavenger]]s, condors eat carcasses of game that have been shot but not retrieved, and with them the fragments from lead bullets; this increases their lead levels.<ref name="Green08PLoS">{{cite journal | vauthors = Green RE, Hunt WG, Parish CN, Newton I | title = Effectiveness of action to reduce exposure of free-ranging California condors in Arizona and Utah to lead from spent ammunition | journal = PLOS ONE | volume = 3 | issue = 12 | page = e4022 | year = 2008 | pmid = 19107211 | pmc = 2603582 | doi = 10.1371/journal.pone.0004022 | veditors = Pizzari T | bibcode = 2008PLoSO...3.4022G | doi-access = free }}</ref> Among condors around the [[Grand Canyon]], lead poisoning due to eating lead shot is the most frequently diagnosed cause of death.<ref name="Green08PLoS"/> To protect this species, in areas designated as the California condor's range, the use of projectiles containing lead has been banned to hunt deer, feral pigs, elk, pronghorn antelope, coyotes, ground squirrels, and other non-game wildlife.<ref name="leadout"/> Also, conservation programs exist that routinely capture condors, check their blood lead levels, and treat cases of poisoning.<ref name="Green08PLoS"/>
{{Clear}}

==See also==
* [[2015 incidents of lead in drinking water in Hong Kong]]
* [[Lead abatement]]
* [[Lead-based paint in the United States]]
* [[Lead Exposure Elimination Project]]
* [[Lead#Production|Lead production and applications]]
* [[Particulates]]
* [[Renovation]]
* [[Sick building syndrome]]
* [[Substance-induced psychosis]]
* [[Risk factors of schizophrenia]]

==Notes==
{{reflist|refs=
<ref name="Pearson03">[[#CITEREFPearson03|Pearson, Schonfeld (2003)]] p. 369</ref>
<ref name="Pearson03-370">[[#CITEREFPearson03|Pearson, Schonfeld (2003)]] p. 370</ref>
<ref name="leadout">{{cite web | url = http://www.dfg.ca.gov/wildlife/hunting/condor/ | title = Get the Lead Out (Protecting the Condor) | access-date = 2009-07-28 | publisher = California Department of Fish and Game | archive-date = 2007-12-19 | archive-url = https://web.archive.org/web/20071219020004/http://www.dfg.ca.gov/wildlife/hunting/condor/ | url-status = dead }}</ref>
}}

'''References'''
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* {{cite book |title= Goodman and Gilman's Manual of Pharmacology and Therapeutics|chapter=Principles of toxicology | veditors = Brunton LL, Goodman LS, Blumenthal D, Buxton I, Parker KL |year= 2007 |publisher= McGraw-Hill Professional |isbn=978-0-07-144343-2 |ref=CITEREFBrunton07}}
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* {{cite book |title=Casarett and Doull's Toxicology: The Basic Science of Poisons |edition=7th |chapter= Toxic effects of metals | veditors = Casarett LJ, Klaassen CD, Doull J |year= 2007 |publisher= McGraw-Hill Professional |isbn= 978-0-07-147051-3|ref= CITEREFCasarett07}}
* {{cite book | vauthors = Chisolm JJ |title= Oski's Essential Pediatrics |edition= 2nd |chapter= Lead poisoning | veditors = Crocetti M, Barone MA, Oski FA |year= 2004 |publisher= Lippincott Williams & Wilkins |isbn= 978-0-7817-3770-8 |ref= CITEREFChisolm04 |chapter-url-access= registration |chapter-url= https://archive.org/details/oskisessentialpe0002unse }}
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* {{cite book | vauthors = Dart RC, Hurlbut KM, Boyer-Hassen LV |title= Medical Toxicology |edition=3rd |chapter= Lead | veditors = Dart RC |year= 2004 |publisher= Lippincott Williams & Wilkins |isbn= 978-0-7817-2845-4 |ref = CITEREFDart04}}
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* {{cite book | vauthors = Grant LD |title= Environmental Toxicants: Human Exposures and Their Health Effects |edition=3rd |chapter= Lead and compounds | veditors = Lippmann M |year= 2009 |publisher=Wiley-Interscience |isbn= 978-0-471-79335-9|ref=CITEREFGrant09}}
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* {{cite book | vauthors = Henretig FM |title= Goldfrank's Toxicologic Emergencies |edition=8th |chapter= Lead | veditors = Goldfrank LR |year= 2006 |publisher= McGraw-Hill Professional |isbn= 978-0-07-143763-9 |ref= CITEREFHenretig06}}
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* {{cite book | vauthors = Kosnett MJ |title=Critical Care Toxicology: Diagnosis and Management of the Critically Poisoned Patient |chapter= Lead| veditors = Brent J |year= 2005 |publisher= Gulf Professional Publishing |isbn= 978-0-8151-4387-1|ref=CITEREFKosnett05}}
* {{cite book | vauthors = Kosnett MJ |title= Basic and Clinical Pharmacology |chapter=Heavy metal intoxication and chelators | veditors =  Katzung BG |year= 2007 |publisher= McGraw-Hill Professional |isbn= 978-0-07-145153-6 |ref=CITEREFKatzung07}}
* {{cite book | vauthors = Kosnett MJ |title= Poisoning and Drug Overdose |edition=5th |chapter= Lead | veditors = Olson KR |publisher= McGraw-Hill Professional |isbn= 978-0-07-144333-3 |page= 2006 |ref=CITEREFKosnett06Pois|date= 2006-09-18 }}
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* {{cite book | vauthors = Menkes JH|title= Child Neurology |edition=7th |chapter=Toxic and nutritional disorders | veditors = Menkes JH, Sarnat HB, Maria BL |year= 2006 |publisher= Lippincott Williams & Wilkins |isbn=978-0-7817-5104-9 |page=706 |ref= CITEREFMenkes06}}
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* {{cite book | vauthors = Mycyk M, Hryhorczuk D, Amitai Y |title= Pediatric Toxicology: Diagnosis and Management of the Poisoned Child |chapter= Lead | veditors = Erickson TB, Ahrens WR, Aks S, Ling L |year= 2005 |publisher= McGraw-Hill Professional|isbn=978-0-07-141736-5 |ref= CITEREFMycyk05}}
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{{refend}}

== Further reading ==
{{refbegin}}
* {{cite web |vauthors=Binns HJ, Ricks OB |title=Helping Parents Prevent Lead Poisoning |work=ERIC Digest |url=http://www.ericdigests.org/2003-2/lead.html |access-date=2004-06-23 |archive-date=2004-05-05 |archive-url=https://web.archive.org/web/20040505072838/http://www.ericdigests.org/2003-2/lead.html |url-status=dead }}
* {{cite journal |last=Karalus |first=Daniel E |title=Review: The Great Lead Water Pipe Disaster |journal=Electronic Green Journal |volume=1 |issue=29 |year=2010 |doi=10.5070/G312910819 |url=http://escholarship.org/uc/item/6m68b873 |doi-access=free }}
* {{cite book|last1=Küpper |first1= Hendrik |chapter= Chapter 15. Lead Toxicity in Plants|pages=491–500|publisher= de Gruyter|date= 2017|series= Metal Ions in Life Sciences|volume=17|title=Lead: Its Effects on Environment and Health| veditors = Astrid S, Helmut S, Sigel RK |doi=10.1515/9783110434330-015|pmid= 28731308|isbn= 978-3-11-043433-0}}
* {{cite journal |vauthors=Liu KS, Hao JH, Zeng Y, Dai FC, Gu PQ |title=Neurotoxicity and biomarkers of lead exposure: a review |journal=Chin Med Sci J |volume=28 |issue=3 |pages=178–88 |date=September 2013 |pmid=24074621 |doi=10.1016/s1001-9294(13)60045-0 |url=}}
* {{cite journal |vauthors=Ordemann JM, Austin RN |title=Lead neurotoxicity: exploring the potential impact of lead substitution in zinc-finger proteins on mental health |journal=Metallomics |volume=8 |issue=6 |pages=579–88 |date=June 2016 |pmid=26745006 |doi=10.1039/c5mt00300h |url=|doi-access=free }}
* {{cite journal |vauthors=Vorvolakos T, Arseniou S, Samakouri M |title=There is no safe threshold for lead exposure: Α literature review |journal=Psychiatriki |volume=27 |issue=3 |pages=204–214 |date=2016 |pmid=27837574 |doi=10.22365/jpsych.2016.273.204 |url=}}
{{refend}}

== External links ==
{{refbegin}}
<!--
TREATMENT-->
* {{cite web |author=Agency for Toxic Substances and Disease Registry |url=https://www.atsdr.cdc.gov/csem/csem.html |title=Lead Toxicity |work=Environmental Health and Medicine Education |publisher=U.S. [[Department of Health and Human Services]] |id=Course: WB 1105 |date=August 20, 2007 }}
* {{cite web  |author=Agency for Toxic Substances and Disease Registry |url=https://wwwn.cdc.gov/TSP/MMG/MMGDetails.aspx?mmgid=1203&toxid=22 |title=Lead &#124; Medical Management Guidelines &#124; Toxic Substance Portal}}
<!--
GENERAL-->
* {{cite web  |author=Agency for Toxic Substances and Disease Registry |url=https://wwwn.cdc.gov/TSP/ToxProfiles/ToxProfiles.aspx?id=96&tid=22 |title=Toxicological Profile for Lead | date=2020 |doi=10.15620/cdc:95222}} Peer-reviewed profile that characterizes the toxicology and health effects information, identifies and reviews the key literature that describes lead's toxicological properties.
* {{cite web |author=Health and Safety Executive UK |title=Lead |work=Working safely with lead |publisher=HSE |url=http://www.hse.gov.uk/lead/ }}
* {{cite news |vauthors=Katz NL |title=City payout to Brooklyn family largest ever in lead poisoning |newspaper=NY Daily News |date=June 26, 2007 |url=http://www.nydailynews.com/news/2007/06/26/2007-06-26_12m_for_toxic_hell.html |access-date=2009-09-28 |archive-date=2011-06-03 |archive-url=https://web.archive.org/web/20110603180052/http://www.nydailynews.com/news/2007/06/26/2007-06-26_12m_for_toxic_hell.html |url-status=dead }}
* {{cite web |author=National Institute for Occupational Safety and Health |title=Lead |work=NIOSH Workplace Safety & Health Topics |publisher=Centers for Disease Control and Prevention |url=https://www.cdc.gov/niosh/topics/lead/ |date=2018-06-20 }}
* {{cite web |author=National Pollutant Inventory |title=Lead and compounds: Health effects |work=Fact Sheets |publisher=Department of Sustainability, Environment, Water, Population and Communities |location=Canberra, Australia |url=http://www.npi.gov.au/substances/lead/health.html |url-status=dead |archive-url=https://web.archive.org/web/20120320030408/http://www.npi.gov.au/substances/lead/health.html |archive-date=2012-03-20 }}
* {{cite web |author=National Safety Council |title=Lead Poisoning |work=Fact Sheets |publisher=National Safety Council |location=Itasca, Illinois, U.S. |year=2008 |url=http://www.nsc.org/NSCDocuments_Advocacy/Fact%20Sheets/Lead-Poisoning-Fact-Sheet.pdf |access-date=2016-06-11 |archive-url=https://web.archive.org/web/20171222135408/http://www.nsc.org/NSCDocuments_Advocacy/Fact%20Sheets/Lead-Poisoning-Fact-Sheet.pdf |archive-date=2017-12-22 |url-status=dead |author-link=National Safety Council }}
<!--
Regulations-->
*{{cite web | author=The Associated Press | title=Biden administration proposes strictest lead pipe rules in more than three decades | website=NPR | date=30 Nov 2023 | url=https://www.npr.org/2023/11/30/1216034743/lead-pipe-rules-drinking-water-epa-flint | access-date=13 Mar 2024}}
*{{cite web | last=Davenport | first=Coral | title=E.P.A. Proposes Tighter Limits on Lead Dust in Homes and Child Care Facilities | website=The New York Times | date=12 Jul 2023 | url=https://www.nytimes.com/2023/07/12/climate/epa-lead-dust-homes.html | access-date=13 Mar 2024}}
{{refend}}
  
{{Medical resources
| ICD10           = {{ICD10|T|56|0|t|51}}
| ICD9            = {{ICD9|984.9}}
| DiseasesDB      = 7307
| eMedicineSubj   = article
| eMedicineTopic  = 815399
| MedlinePlus     = 002473
| MeshID          = D007855
| Orphanet        = 330015
}}

{{Poisoning and toxicity}}
{{Elements in biology}}
{{Pigmentation disorders}}
{{Consumer Food Safety}}
{{Occupational safety and health}}
{{good article}}
{{Authority control}}

{{DEFAULTSORT:Lead Poisoning}}
[[Category:Lead poisoning| ]]
[[Category:Environmental impact by effect]]
[[Category:Occupational diseases]]
[[Category:Mass poisoning]]
[[Category:Disturbances of human pigmentation]]
[[Category:Intellectual disability]]
[[Category:Biology of attention deficit hyperactivity disorder]]
[[Category:Wikipedia medicine articles ready to translate]]