Heavy Metal Toxicity and its Impact is . . .
Global Incidence of Lead Toxicity
The NHANES III study published in the Archives of Internal Medicine in 2003 showed that there was an increase in death rates of cancers and heart disease (approx 70%) associated with low lead levels in blood.
Intravenous EDTA is FDA approved for treating acute lead poisoning, however we believe that Detoxamin (EDTA in suppository form) can help reduce cumulative low levels of lead when used as preventative therapy.
Facts of lead poisoning worldwide
US research predicts that some 30 million Americans are at risk from early death from lead due to having exceeded a blood lead level of 20 µg/dL at least once in their adulthood (Lustberg and Silbergeld, 2002). If the US rate of exposure – remembering that the US was the first country to begin phasing out the most dispersive use of lead, leaded gasoline in 1972 (50 years after it’s introduction) – has such a huge predicted impact in the US, then what must be the impact of lead on the global early death rate and indeed on the life quality of the ageing? The Global Lead Advice and Support Service (GLASS) predicts that researching appropriate advice on treatment or care of the ageing population will be a huge task of lead poisoning management for the future, as we move at least one lifetime away from the 1970s and 1980s, the great era of lead poisoning due to leaded petrol. “With so many people having higher blood lead levels in the past than today, it is little wonder that we associate ageing with many of the effects of lead poisoning, but especially:- poor memory and hearing, falls (from loss of balance), reduced sperm count, loss of libido, strokes and heart attacks (from raised blood pressure), tooth decay, Alzheimers disease. It is fair to say that all these effects of lead add up to a reasonable description of what we think of as “normal” ageing and it is certainly time that we measured blood lead levels in older people who display these symptoms before discounting their symptoms as just “a natural part of getting old” (Bailey, 2003)
The World Health Organisation (WHO) estimates that there are 120 million people worldwide who are lead poisoned i.e. have a blood lead level greater than 10 micrograms per decilitre (µg/dL) (Fewtrell et al, 2003). Recent research indicates that the aim should be to get everyone below 5 µg/dL. So it would be more reasonable to see our aim as reducing the blood lead levels of the 240 million people WHO estimates have a blood lead level greater than 5 µg/dL. But actually, looking at the blood lead surveys that have been done, even this huge figure would seem to be an underestimation. Sure, the only Australian blood lead survey of children in 1996 found 7.3% of preschoolers were lead poisoned (and this is probably an underestimate) but in a Chinese meta-analysis more than one third of the children in China were found to have blood lead levels greater than 10µg/dL. In an Indian survey of 2,031 children and adults in 5 cities, more than half of them had blood lead levels greater than 10 µg/dL (George Foundation, 1999). And in just one African city Johannesburg, which may be representative of all the cities in the 43 African countries still using leaded petrol – 78% of the children were lead poisoned as shown in Table 2.
Blood Lead Levels (BLL) of children in various countries
|Country||Date||BLL (median)||BLL>10 µg/dL|
|South Africa1||2002||11.9 µg/dL||78%|
|Jamaica2Rural areasUrban areascontaminated area, the site of a former lead ore processing plant||2000||9.2 µg/dL16.6 µg/dL35 µg/dL*||42%71%-|
|India – 1852 urban children3||1999||–||51.4%[12.6%>20µg/dL]|
|Europe/Urban area6||N/A||–||0.1 – 30.2%|
|* reduced now by implementation of mitigation strategies1 Mathee et al., 2002; 2 Lalor et al., 2001; 3 George Foundation, 1999 4 Wang and Zhang, 2004; 5 CDC, 2005; 6 WHO, 2004; 7 Donovan 1996|
It is salutary, to reflect on just how much lead is in a “modern” human, and how badly poisoned some people are, compared to humans of earlier times. Henry Falk’s Case Study of Lead Poisoning (Falk, 2003), reports that people living right next to backyard smelters, mines or shops where lead acid batteries are repaired, typically have a higher blood lead level than 10µg/dL (Falk, 2003). The results of a study by Wang Sun-qin, Zhang Jin-liang in 2004 showed that blood lead levels among Chinese children are very high and are considered to be one potential environmental risk factor for children’s development (Wang and Zhang, 2004).
For centuries, lead has been mined and used in industry and in household products. Modern industrialization, with the introduction of lead in mass-produced plumbing, solder used in food cans, paint, ceramic ware, and countless other products resulted in a marked rise in population exposures in the 20th century.
The dominant source of worldwide dispersion of lead into the environment (and into people) for the past 50 years has clearly been the use of lead organic compounds as antiknock motor vehicle fuel additives. Since leaded gasoline was introduced in 1923, its combustion and resulting contamination of the atmosphere has increased background levels everywhere, including the ice cap covering Northern Greenland where there is no industry and few cars and people. Although a worldwide phase-out of leaded gasoline is in progress (see http://www.earthsummitwatch.org/gasoline.html for details), it is still being used all over the world.
The current annual worldwide production of lead is approximately 5.4 million tons and continues to rise. Sixty percent of lead is used for the manufacturing of batteries (automobile batteries, in particular), while the remainder is used in the production of pigments, glazes, solder, plastics, cable sheathing, ammunition, weights, gasoline additive, and a variety of other products. Such industries continue to pose a significant risk to workers, as well as surrounding communities.
In response to these risks, many developed countries over the last 25 years have implemented regulatory action that has effectively decreased actual exposures to the general population. However, exposures remain high or are increasing in many developing countries through a rapid increase in vehicles combusting leaded gasoline and polluting industries (some of which have been “exported” by corporations in developed countries seeking relief from regulations. Moreover, some segments of the population in developed countries (such as the U.S.) remain at high risk of exposure because of the persistence of lead paint, lead plumbing, and lead-contaminated soil and dust, particularly in areas of old urban housing. A number of factors can modify the impact of lead exposures. For example, water with a lower pH (such as drinking water stemming from the collection of untreated “acid rain”) will leach more lead out of plumbing connected by lead solder than more alkaline water.2 Lead from soil tends to concentrate in root vegetables (e.g., onion) and leafy green vegetables (e.g., spinach). Individuals will absorb more lead in their food if their diets are deficient in calcium, iron, or zinc. Other more unusual sources of lead exposure also continue to be sporadically found, such as improperly glazed ceramics, lead crystal, imported candies, certain herbal folk remedies, and vinyl plastic toys.
Lead has been the intensefocus of environmental health research for many decades. Studies in humans were greatly assisted by the development of methods (such as graphite furnace atomic absorption spectroscopy) for the accurate and reliable measurement of lead in blood (measured in units of micrograms per deciliter [mg/dL]), a technique that is now widely available and used for surveillance and monitoring, as well as research. The general body of literature on lead toxicity indicates that, depending on the dose, lead exposure in children and adults can cause a wide spectrum of health problems, ranging from convulsions, coma, renal failure, and death at the high end to subtle effects on metabolism and intelligence at the low end of exposures. Children (and developing fetuses) appear to be particularly vulnerable to the neurotoxic effects of lead. A plethora of well-designed prospective epidemiologic studies has convincingly demonstrated that low-level lead exposure in children less than five years of age (with blood lead levels in the 5-25 mg/dL range) results in deficits in intellectual development as manifested by lost intelligence quotient points.6 As a result, in the U.S., the Centers for Disease Control (CD) lowered the allowable amount of lead in a child’s blood from 25 to 10 mg/dL and recommended universal blood lead screening of all children between the ages of six months and five years. (For more details, see http://www.cdc.gov/nceh/lead/lead.htm.) However, a number of issues still remain unresolved with respect to lead toxicity in children. Among the most important is the risk posed to the fetus posed by mobilization of longlived skeletal stores of lead in pregnant women. Recent research has clearly demonstrated that maternal bone lead stores are mobilized at an accelerated rate during pregnancy and lactation and are associated with decrements in birth weight, growth rate, and mental development. Since bone lead stores persist for decades it is possible that lead can remain a threat to fetal health many years after environmental exposure had actually been curtailed.
In contrast to children, adults are generally allowed by regulations to be exposed to higher amounts of lead. In the U.S., for example, the Occupational Safety and Health Administration requires that the blood lead levels of exposed workers be maintained below 40 mg/dL as a way of preventing toxic effects to nerves, the brain, kidney, reproductive organs, and heart. (For more information, see http://www.osha-slc.gov/OshStd_data/ 1910_1025_APP_C.html.) This standard is probably outdated, however. First, the standard does not protect the fetuses of women who become pregnant while on the job (or even if they leave the job for several years because of the issue of bone lead mobilization, as discussed above). Second, recent epidemiologic studies have linked blood lead levels in the range of 7-40 mg/dL with evidence of toxicity in adults, such as neurobehavioral decrements and renal impairments. Third, recent studies using a newly developed technique, K-x-ray fluorescence, to directly measure bone lead levels (as opposed to blood lead levels) have provided evidence demonstrating that cumulative lead exposure in individuals with blood lead levels well below 40 mg/dL is a major risk factor for the development of hypertension, cardiac conduction delays and cognitive impairments. Finally, even as research progresses to delineate the full toxicologic implications of lead exposure, investigations at the interface of genetics and environmental health are beginning to uncover subgroups of individuals who may be particularly susceptible to the toxicity of lead.
Epidemiology of lead exposure
Since lead has been used widely for centuries, the effects of exposure are worldwide. Environmental lead is ubiquitous, and everyone has some measurable blood lead level. Lead is one of the largest environmental medicine problems in terms of numbers of people exposed and the public health toll it takes. Lead exposure accounts for about 0.2% of all deaths and 0.6% of disability adjusted life years globally.
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. In all countries that have banned leaded gasoline, average blood lead levels have fallen sharply. However, some developing countries still allow leaded gasoline, which is the primary source of lead exposure in most developing countries. Beyond exposure from gasoline, the frequent use of pesticides in developing countries adds a risk of lead exposure and subsequent poisoning. Poor children in developing countries are at especially high risk for lead poisoning. Of North American children, 7% have blood lead levels above 10 μg/dL, whereas among Central and South American children, the percentage is 33 to 34%. About one fifth of the world’s disease burden from lead poisoning occurs in the Western Pacific, and another fifth is in Southeast Asia.
In developed countries, nonwhite people with low levels of education living in poorer areas are most at risk for elevated lead. In the US, the groups most at risk for lead exposure are the impoverished, city-dwellers, and immigrants. 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. 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 for elevated lead exposure include alcohol consumption and smoking (possibly because of contamination of tobacco leaves with lead-containing pesticides). 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. 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.
In adults, blood lead levels steadily increase with increasing age. In adults of all ages, men have higher blood lead levels than women do. Children are more sensitive to elevated blood lead levels than adults are. 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. Children ages 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. Blood levels usually peak at about 18–24 months old. In many countries including the US, household paint and dust are the major route of exposure in children.
Estimated costs (billions) of pediatric disease of environmental origin, United States, 1997.
Disease Best estimate Low estimate High estimate
Lead poisoning $43.4 $43.4 $43.4
Asthma $2.0 $0.7 $2.3
Cancer $0.3 $0.2 $0.7
Neurobehavioral disorders $9.2 $4.6 $18.4
Total $54.9 $48.8 $64.8
Environmental Pollutants and Disease in American Children: Estimates ofMorbidity, Mortality, and Costs for Lead Poisoning,Asthma, Cancer, andDevelopmental Disabilities
Philip J. Landrigan, 1,2 Clyde B. Schechter, 2 Jeffrey M. Lipton,3 Marianne C. Fahs,4 and Joel Schwartz5
The Center for Children’s Health and the Environment, The Department of Community and Preventive Medicine, and The Departmentof Pediatrics, Mount Sinai School of Medicine, New York, New York, USA; The Health Policy Research Center, New School for SocialResearch, New York, New York, USA; and The Environmental Epidemiology Program, Harvard School of Public Health, Boston,Massachusetts, USA
In this study, we aimed to estimate the contribution of environmental pollutants to the incidence, prevalence, mortality, and costs of pediatric disease in American children. We examined four categories of illness: lead poisoning, asthma, cancer, and neurobehavioral disorders. To estimate the proportion of each attributable to toxins in the environment, we used an environmentally attributable fraction (EAF) model. EAFs for lead poisoning, asthma, and cancer were developed by panels of experts through a Delphi process, whereas that for neurobehavioral disorders was based on data from the National Academy of Sciences. We define environmental pollutants as toxic chemicals of human origin in air, food, water, and communities. To develop estimates of costs, we relied on data from the U.S. Environmental Protection Agency, Centers for Disease Control and Prevention, National Center for Health Statistics, the Bureau of Labor Statistics, the Health Care Financing Agency, and the Practice Management Information Corporation. EAFs were judged to be 100% for lead poisoning, 30% for asthma (range, 10–35%), 5% for cancer (range, 2–10%) and 10% for neurobehavioral disorders (range, 5–20%). Total annual costs are estimated to be $54.9 billion (range $48.8–64.8 billion): $43.4 billion for lead poisoning, $2.0 billion for asthma, $0.3 billion for childhood cancer, and $9.2 billion for neurobehavioral disorders. This sum amounts to 2.8 percent of total U.S. health care costs. This estimate is likely low because it considersonly four categories of illness, incorporates conservative assumptions, ignores costs of painand suffering, and does not include late complications for which etiologic associations are poorlyquantified. The costs of pediatric environmental disease are high, in contrast with the limitedresources directed to research, tracking, and prevention. Environ Health Perspect 110:721–728 (2002). [Online 31 May 2002] http://ehpnet1.niehs.nih.gov/docs/2002/110p721-728landrigan/abstract.html
Lead Blood Levels in the US Morbidity and Mortality November 29, 2013 / 62(47);967-971
Over the past several decades there has been a remarkable reduction in environmental sources of lead, improved protection from occupational lead exposure, and an overall decreasing trend in the prevalence of elevated blood lead levels (BLLs) in U.S. adults. As a result, the U.S. national BLL geometric mean among adults was 1.2 µg/dL during 2009–2010 (1). Nonetheless, lead exposures continue to occur at unacceptable levels (2). Current research continues to find that BLLs previously considered harmless can have harmful effects in adults, such as decreased renal function and increased risk for hypertension and essential tremor at BLLs <10 µg/dL (3–5). CDC has designated 10 µg/dL as the reference BLL for adults; levels ≥10 µg/dL are considered elevated (2). CDC’s Adult Blood Lead Epidemiology and Surveillance (ABLES) program tracks elevated BLLs among adults in the United States (2). In contrast to the CDC reference level, prevailing Occupational Safety and Health Administration (OSHA) lead standards allow workers removed from lead exposure to return to lead work when their BLL falls below 40 µg/dL (6). During 2002–2011, ABLES identified 11,536 adults with very high BLLs (≥40µg/dL). Persistent very high BLLs (≥40 µg/dL in ≥2 years) were found among 2,210 (19%) of these adults. Occupational exposures accounted for 7,076 adults with very high BLLs (91% of adults with known exposure source) and 1,496 adults with persistent very high BLLs. Adverse health effects associated with very high BLLs (4,5,7) underscore the need for increased efforts to prevent lead exposure at workplaces and in communities.
Forty-one states participated in the ABLES program in 2011.* These states received adult BLL data from laboratories and physicians through mandatory reporting. Adults were defined as persons aged ≥16 years at the time of BLL testing. Each state ABLES program assigned a unique identifier to each adult to protect individual privacy while permitting longitudinal analyses (2). For this analysis, a BLL ≥40 µg/dL was defined as a very high BLL. A very high BLL measured over a period ≥2 years was defined as a persistent very high BLL. The number of adults with very high BLLs and the number with persistent very high BLLs during 2002–2011 were counted. Persistent very high BLLs can result in spontaneous abortion, reduced newborn birthweight, neurocognitive deficits, sperm abnormalities, subclinical peripheral neuropathy, hypertension, anemia, kidney dysfunction, and nonspecific symptoms (4,5). As part of their regular activities, and to the extent resources allow, state ABLES programs 1) investigate the circumstances associated with reports of elevated BLLs; 2) contact health-care providers, workers, and employers to gather industry and occupation data and additional exposure information and provide information and educational materials; and 3) refer employers in occupational cases to OSHA offices for technical assistance or enforcement of the lead standards.
From 2002 to 2011, a total of 11,536 adults had very high BLLs among the 1,201,669 adults reported to the ABLES program during this period. Among these adults, 2,210 (19%) had persistent very high BLLs, 1,487 (13%) had BLLs ≥60 µg/dL, and 96 had BLLs ≥60 µg/dL for ≥2 years. A total of 7,076 adults with very high BLLs (91% of adults with known exposure source) were exposed at work and 1,496 of these had persistent very high BLLs (93% of adults with known exposure source). These 7,076 workers were predominantly employed in the manufacturing, construction, services, or mining sectors. Within this group, 49% of the workers were employed in three subsectors (i.e., battery manufacturing, nonferrous metal production and processing, and painting and wall covering contractors). Shooting firearms; remodeling, renovating, or painting; and using lead-containing alternative medicines were the most common sources for nonoccupational very high BLLs. The following four case histories illustrate the persistent problem of adults with very high BLLs in the United States.
Worker A. Worker A is a man aged 48 years who was working for a bridge painting firm and was responsible for recycling grit and steel shot from sandblasting operations. His primary protection from lead exposure was an air-supplied sandblasting hood. This worker had BLLs of 67 µg/dL in May and June of 2010. He was removed from all work and received chelation treatments (therapy to remove heavy metals from the body). His BLL dropped to 42µg/dL in July and to 26 µg/dL in September 2010. At last contact in February 2011, he continued to be removed from work per physician orders.
Worker B. Worker B is a painter for a small construction company, aged 46 years, who, in December 2007, was seen in a hospital emergency department because of severe stomach pain. His BLL was 143 µg/dL; he was given a chelation treatment and was followed at an occupational health clinic. His last BLL on record in February 2010 was 13 µg/dL. At the time of initial testing, this worker was scraping paint from a house that was >100 years old. He used no respirator and wore no protective clothing except for gloves. He was not informed about lead hazards. His employer did not provide laundry services or disposable clothing. No other source of lead exposure was identified.
Worker C. Worker C is a man aged 45 years who began working for a battery manufacturing company in May 2000. He worked in maintenance and was responsible for cleaning under lead pots. He did not use a respirator as instructed by his employer because of the heat in the factory. His first BLL was 25µg/dL in March 2001, and by August 2002 his BLL was 60 µg/dL. Because of the very high BLL, the company moved him into a job with low likelihood of lead exposure. After his BLL dropped below 40 µg/dL in November 2002, he was reassigned to job duties with high likelihood of lead exposure. When his BLL rose to 40 µg/dL again in April 2003, the company issued him a full-face respirator and required him to use it. He was also instructed to shower at the end of the day and for breaks and lunch. He later transferred into jobs at the plant with lower lead exposures and his BLL continued to drop. His most recent BLL in August 2011 was 14 µg/dL.
Adult D. Adult D is a man aged 60 years with a BLL of 84 µg/dL in March 2009 who had no known occupational exposure. His known exposures were target shooting at an indoor shooting range and casting bullets. He was given a chelation treatment in April 2009. Approximately 100 BLLs analyzed through June 2012 ranged from 6 µg/dL to 84 µg/dL, with a mean of 28 µg/dL. He and his physician were informed about the detrimental effects of lead and how to limit his exposure, but the patient continues his two hobbies.
Kathryn Kirschner, Indiana Univ. Kathy Leinenkugel, MPA, Div of Environmental Health, Iowa Dept of Public Health. Mike Makowski, MPH, Div of Environmental Health Epidemiology, Pennsylvania Dept of Health. Alicia M. Fletcher, MPH, Bur of Occupational Health and Injury Prevention, New York State Dept of Health. Carol R. Braun, Bur of Environmental Epidemiology, Missouri Dept of Health and Senior Svcs. Walter A. Alarcon, MD, Marie H. Sweeney, PhD, Geoffrey M. Calvert, MD, Div of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, CDC. Corresponding contributor: Walter A. Alarcon,email@example.com, 513-841-4451.
Reducing lead exposures at work and in the community is essential to avoid adverse health effects in humans. Reducing by 10% the rate of persons who have elevated BLLs (i.e., BLLs ≥10 µg/dL) from work exposures is a Healthy People 2020 objective (OHS-7) (8). The 2010 baseline rate for BLLs ≥10 µg/dL is 26.4 adults per 100,000 employed adults (2). Reducing adverse health effects resulting from lead exposures requires 1) adherence to engineering controls and safe work practices; 2) BLL testing and management of elevated BLLs according to the most current medical guidelines and recommendations; and 3) education in the workplace and community (4–7,9). OSHA lead standards give the examining physician broad flexibility to tailor special protective procedures to the needs of individual employees (6). Therefore, the most current guidelines for management of lead-exposed adults (4,5,7) should be implemented by the medical community at the current CDC reference BLL of 10 µg/dL (2), including consideration of removal from lead exposure at lower levels than the current OSHA lead standards require. Increasing the number and timeliness of referrals to OSHA of workplaces identified by state ABLES programs fosters prompt intervention and mitigation of lead exposure hazards.
The findings of this report demonstrate that many adults in the United States continue to have very high BLLs. The fact that some adults had persistent very high BLLs is of grave concern. These adults were chronically exposed to lead above BLLs known to cause neurologic, cardiovascular, reproductive, hematologic, and kidney adverse effects (3–5). The risks for adverse chronic health effects are even higher if the exposure is maintained for many years (4,5,7).
The findings in this report are subject to at least three limitations, all of which suggest that ABLES underestimates the number of adults with elevated BLLs. First, employers might not provide BLL testing to all lead-exposed workers as required by OSHA regulations (10). Second, nonoccupationally exposed adults might not be tested. Finally, some laboratories might not report all tests as required by state laws or regulations (Susan Payne, California Department of Public Health, personal communication, June 18, 2012).
Possible factors contributing to the persistence of very high BLLs include 1) prevailing OSHA lead standards require medical removal from lead exposures only after a construction worker’s BLL reaches or exceeds 50 µg/dL or a general industry worker’s BLL reaches or exceeds 60 µg/dL; 2) examining physicians rarely recommend more stringent worker protections, which the OSHA lead standards allow but do not require; 3) some employers fail to implement appropriate engineering protections and workplace controls; 4) some adults fail to comply with safe practices and behaviors; and 5) state ABLES programs do not always have the resources to investigate and refer to OSHA all cases with very high BLLs.
Very high BLLs continue to be documented in adults in the United States. Actions that might decrease the number of adults with harmful BLLs include 1) increased employer efforts to reduce work-related lead exposure (6,9) and to comply with current guidance (4,7) for testing and managing lead-exposed workers; 2) adherence by lead-exposed workers to safe work practices, such as properly using personal protective equipment, washing before eating, and showering and changing clothes before going home; 3) education of the medical community to use current guidelines and recommendations for management of lead-exposed adults with BLLs ≥10 µg/dL (4,5,7); and 4) increased involvement of the public health community to prevent nonoccupational lead exposures.
ABLES program coordinators in Alaska, Alabama, Arizona, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Montana, North Carolina, Nebraska, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Utah, Vermont, Washington, Wisconsin, and Wyoming.
- Fourth national report on human exposure to environmental chemicals. Updated tables, September 2013. Atlanta, GA: US Department of Health and Human Services, CDC; 2012. Available athttp://www.cdc.gov/exposurereport/pdf/fourthreport_updatedtables_sep2013.pdf .
- Adult Blood Lead Epidemiology and Surveillance (ABLES). Cincinnati, OH: US Department of Health and Human Services, CDC, National Institute for Occupational Safety and Health; 2013. Available athttp://www.cdc.gov/niosh/topics/ables/description.html.
- National Toxicology Program. Health effects of low-level lead evaluation. Research Triangle Park, NC: US Department of Health and Human Services, National Toxicology Program; 2013. Available athttp://ntp.niehs.nih.gov/go/36443.
- Association of Occupational and Environmental Clinics. Medical management guidelines for lead-exposed adults. Washington, DC: Association of Occupational and Environmental Clinics; 2007. Available athttp://www.aoec.org/documents/positions/MMG_FINAL.pdf .
- Kosnett MJ, Wedeen, RP, Rothenberg SJ, et al. Recommendations for medical management of adult lead exposure. Environ Health Perspect 2007;115:463–71.
- Occupational Safety and Health Administration. Lead standards: general industry (29 CFR 1910.1025) and construction industry (29 CFR 1926.62). Washington, DC: US Department of Labor, Occupational Safety and Health Administration; 1978. Available athttps://www.osha.gov/sltc/lead.
- California Department of Public Health. Medical guidelines for the lead-exposed worker. Richmond, CA: California Department of Public Health, Occupational Lead Poisoning Prevention Program; 2009. Available athttp://www.cdph.ca.gov/programs/olppp/documents/adultmgtguide.pdf .
- US Department of Health and Human Services. Healthy people 2020: occupational safety and health objective 7. Washington, DC: US Department of Health and Human Services; 2013. Available athttp://www.healthypeople.gov/2020/topicsobjectives2020/objectiveslist.aspx?topicid=30.
- Occupational Safety and Health Administration. OSHA technical manual (OTM). Section V: chapter 3. Controlling lead exposures in the construction industry: engineering and work practice controls. Washington, DC: US Department of Labor, Occupational Safety and Health Administration; 1999. Available athttp://www.osha.gov/dts/osta/otm/otm_v/otm_v_3.html#2.
- Whittaker SG. Lead exposure in radiator repair workers: a survey of Washington State radiator repair shops and review of occupational lead exposure registry data. J Occup Environ Med 2003;45:724–33.
* Federal funding for state ABLES program was discontinued in September 2013. The ABLES program continues to provide technical assistance to states with adult blood lead surveillance programs and maintains the ABLES website for reporting ongoing analyses of ABLES data.
What is already known on this topic?
The vast majority of elevated blood lead levels (BLLs) in the United States are workplace-related. Most lead exposures at work occur in the manufacturing, construction, services, and mining industries. Current research has found that even BLLs <10 µg/dL can cause harm in adults. CDC considers BLLs ≥10µg/dL to be elevated. In contrast to the CDC reference level, prevailing Occupational Safety and Health Administration (OSHA) lead standards allow workers removed from lead exposure to return to lead work when their BLL falls below 40 µg/dL.
What is added by this report?
Data collected by the Adult Blood Lead Epidemiology and Surveillance program during 2002–2011 identified 11,536 adults with very high BLLs (≥40 µg/dL), of whom 19% had elevated BLLs recorded during ≥2 years. Among those with known exposure source, occupational exposures accounted for 91% of adults with very high BLLs.
What are the implications for public health practice?
The finding that many workers have harmful BLLs, some that are persistent for ≥2 years, is of grave concern. Examining physicians should be aware that the OSHA lead standards give them broad flexibility to tailor protections to the worker’s needs, including consideration of removal from lead exposure at BLLs lower than the current OSHA lead standards require. To prevent adverse health outcomes caused by very high BLLs, public health practitioners need to increase lead exposure prevention activities directed at employers, workers, health-care providers, and the community.
|TABLE 1. Number of adults with very high blood lead levels (BLLs ≥40 µg/dL) in multiple years — Adult Blood Lead Epidemiology and Surveillance (ABLES) Program, United States, 2002–2011|
|Characteristic||No. of adults with
BLLs ≥40 µg/dL
|No. of adults with
BLLs ≥60 µg/dL*
|No. of years with
very high BLLs
|Total no. of adults with at least one very high BLL in 10 years||11,536||1,487|
|Total no. of adults with persistent very high BLLs (≥2 years)||2,210||96|
|* Adults with BLLs ≥60 µg/dL are a subset of those adults with BLLs ≥40 µg/dL.|
|TABLE 2. Number and percentage of adults with very high blood lead levels (BLLs ≥40 µg/dL), by industry subsector, and number and percentage by nonoccupational sources of exposure — Adult Blood Lead Epidemiology and Surveillance (ABLES) Program, United States, 2002–2011|
|Characteristic||40–59 µg/dL||≥60 µg/dL||Total (≥40 µg/dL)|
|Unknown exposure source||3,222||(32.1)||575||(38.7)||3,797||(32.9)|
|Industry subsector [NAICS codes]||6,330||746||7,076||(100.0)|
|Battery manufacturing ||1,671||(49.2)||70||(27.7)||1,741|
|Nonferrous metal production and processing [3313 and 3314]||577||(17.0)||47||(18.6)||624|
|Fabricated metal product manufacturing ||257||(7.6)||31||(12.3)||288|
|Other manufacturing industries||644||(19.0)||77||(30.4)||721|
|Painting and wall covering contractors ||890||(56.5)||185||(58.2)||1,075|
|Highway, street, and bridge construction ||262||(16.6)||37||(11.6)||299|
|Site preparation contractors ||96||(6.1)||21||(6.6)||117|
|Other construction industries||327||(20.8)||75||(23.6)||402|
|Services (except public safety)||555||(100.0)||87||(100.0)||642||(9.1)|
|Remediation services ||186||(33.5)||27||(31.0)||213|
|All other amusement and recreation industries ||102||(18.4)||17||(19.5)||119|
|Automotive repair and maintenance ||71||(12.8)||9||(10.3)||80|
|Other services industries||196||(35.3)||34||(39.1)||230|
|Mining (except oil and gas extraction)||428||(100.0)||16||(100.0)||444||(6.3)|
|Lead ore and zinc ore mining ||418||(97.7)||14||(87.5)||432|
|Other mining industries||10||(2.3)||2||(12.5)||12|
|Other/missing industry data||379||72||451||(6.4)|
|Shooting firearms (target shooting)||144||(29.0)||17||(10.2)||161||(24.3)|
|Complementary and alternative medicines (e.g., Ayurvedic medicines)||31||(6.2)||28||(16.9)||59||(8.9)|
|Eating food containing lead||39||(7.8)||18||(10.8)||57||(8.6)|
|Retained bullets (gunshot wounds)||30||(6.0)||15||(9.0)||45||(6.8)|
|Casting (e.g., bullets and fishing weights)||33||(6.6)||6||(3.6)||39||(5.9)|
|Pica (i.e., the eating of nonfood items)||16||(3.2)||20||(12.0)||36||(5.4)|
|Other or unknown nonoccupational source||115||(23.1)||40||(24.1)||155||(23.4)|
|Abbreviation: NAICS = North American Industry Classification System.|
FIGURE. Four adults with very high blood lead levels (BLL ≥40 µg/dL) in multiple years, by year — Adult Blood Lead Epidemiology and Surveillance (ABLES) Program, United States, 2002–2011
Alternate Text: The figure above indicates blood lead levels (BLLs) in four adults with very high BLLs (≥40 μg/dL) in multiple years, by year, in the United States during 2002-2011.
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