Lead at Superfund Sites: Human Health
On this page:
- Lead in the environment
- Possible ways to be exposed to lead
- Symptoms of lead exposure
- Medical tests for lead exposure
- References
For links to information on preventing lead exposure, please refer to the Related Links page.
Lead in the Environment
Lead is a naturally occurring element that can be harmful to humans when ingested or inhaled, particularly to children under the age of six. Lead exposure can cause a number of adverse human health effects. It is particularly detrimental to the neurological development of children. To learn more about the effects of lead exposure and EPA's role in reducing the presence of lead in the environment, visit EPA’s Lead Web page.
For hundreds of years, lead has been mined, smelted, refined and used in products (e.g., as an additive in paint, gasoline, leaded pipes, solder, crystal, and ceramics). Natural levels of lead in U.S. soils range from below detection (0.5 ppm) to greater than 1,200 ppm with a nationwide average of 26 ppm (standard deviation 185 ppm). Mining, smelting and refining activities have resulted in substantial increases in lead levels in the environment, especially near mining and smelting sites. For example, soil lead concentrations higher than 11,000 ppm have been found near some facilities and next to highways (National Research Council, 1980; Chaney et al., 1984; Shacklette et al., 1984).
Lead particles in the environment can attach to dust and be carried long distances in the air. Such lead-containing dust can be removed from the air by rain and deposited on surface soil, where it may remain for many years. In addition, heavy rains may cause lead in surface soil to migrate into ground water and eventually into water systems.
Possible Ways to be Exposed to Lead
Everyone is exposed to background levels of lead, given its widespread distribution. Possible routes of lead exposure include:
- Ingestion of lead-contaminated water, soil, paint chips or dust.
- Inhalation of lead-containing particles of soil or dust in air.
- Ingestion of foods that contain lead from soil or water.
Symptoms of Lead Exposure
Lead poisoning can be a serious public health threat with no unique signs or symptoms. Early symptoms of lead exposure may include:
- persistent fatigue
- irritability
- loss of appetite
- stomach discomfort and/or constipation
- reduced attention span
- insomnia
Failure to treat lead poisoning in the early stages can cause long-term or permanent health damage. Because of the general nature of symptoms at early stages, lead poisoning is often not suspected.
In adults, lead poisoning can cause:
- poor muscle coordination
- nerve damage to the sense organs and nerves controlling the body
- increased blood pressure
- hearing and vision impairment
- reproductive problems (e.g., decreased sperm count)
- retarded fetal development even at relatively low exposure levels
In children, lead poisoning can cause:
- damage to the brain and nervous system
- behavioral problems
- anemia
- liver and kidney damage
- hearing loss
- hyperactivity
- developmental delays
- in extreme cases, death
Although the effects of lead exposure are a potential concern for all humans, young children (less than seven years old) are most at risk (Reagan and Silbergeld, 1989). This increased vulnerability results from a combination of the following factors:
- Children typically have higher intake rates (per unit body weight) for environmental media (such as soil, dust, food, water, air and paint) than adults, since they are more likely to play in dirt and put their hands and other objects in their mouths.
- Children tend to absorb a higher fraction of ingested lead from the gastrointestinal tract than adults.
- Children tend to be more susceptible than adults to the adverse neurological and developmental effects of lead.
- Nutritional deficiencies of iron or calcium, which are common in children, may facilitate lead absorption and exacerbate the toxic effects of lead.
The national average blood lead levels in children have dropped over time as our understanding of lead risk has evolved and as efforts are undertaken to reduce exposure to lead. While banning of lead paint and lead in gasoline were national efforts to stop childhood lead poisoning, contaminated sites require cleanup to reduce exposure to populations nearby.
Medical Tests for Lead Exposure
If you have concerns about possible lead exposure, contact your personal physician or county/state health department. Your doctor can conduct blood tests to determine lead concentrations in your blood. Blood tests are inexpensive and sometimes free; please consult your insurance provider to determine coverage for such tests. Lead in bone and teeth can be measured using x-ray techniques, but this test is not used very often. In communities where houses are old and deteriorating, residents are encouraged to take advantage of available screening programs offered by local health departments and to have children living in the residence checked regularly for lead poisoning. Because the early symptoms of lead poisoning are similar to those of other illnesses, it is difficult to diagnose lead poisoning without medical testing.
References
Chaney, R.L. et al. 1984. The potential for heavy metal exposure from urban gardens and soils, pp. 37-84. In: J.R. Preer ed. Proceedings of the symposium on heavy metals in urban gardens. Agricultural Experiment Station, University of the District of Columbia, Washington, D.C.
National Research Council. 1980. Lead in the human environment. Washington, D.C.: National Academy of Sciences. Report Number PB-82-117136. OSTI Identifier: 5455381; ISBN No. 0309030218.
Reagan, P.L. & E.K. Silbergeld. 1989. Establishing a health based standard for lead in residential soils. In: Hemphill and Cothern, eds. Trace substances in environmental health, supplement to Volume 12, (1990) of Environmental Geochemistry and Health.
Schacklette, H.T., and Boerngen, J.G., Element Concentrations in Soils and Other Surficial Materials of the Conterminous United States, U.S. Geological Survey Professional Paper; 1270, 1984.
U.S. EPA. Air Quality Criteria for Lead (2006) Final Report. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-05/144aF-bF, 2006.