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Lead Poisoning

Lead (Pb) is a heavy metal element that is a known neurotoxicant. It is naturally occurring, but human exposure primarily results from lead made available through industrial uses. In the United States, lead was a component of many house paints until 1978, and until recently was used as an additive in gasoline. Additionally, lead was used in piping and soldering for water systems until the ban of such uses in 1986. Lead-based paint and lead contaminated dust and soil are the primary sources of lead exposure for children in the United States. Contaminated air, water, and food can also be avenues for lead uptake. Fetal and perinatal exposure is also a significant concern. In addition, lead exposure may occur through imported lead-containing toys, vinyl miniblinds, folk medicines and cosmetics, pottery, and other routes that are difficult to identify and control.

Although much progress has been made, childhood lead poisoning remains a critical environmental health concern. Data from 2004 reveal that over 500,000 children in the United States under age six currently experience blood lead levels above the Centers for Disease Control and Prevention blood lead action level of 10 µg/dL, with an overall geometric mean blood lead level of 2.1 µg/dL. Since the late 1970s, mounting research demonstrates that lead causes irreversible, asymptomatic effects far below levels previously considered safe, and potentially at any level of exposure. Low-level lead exposure, including prenatal exposure, has been linked to decreased performance on standardized IQ tests and end-of-grade testing for school-aged children.

Children are not uniformly exposed to lead. The age of the child, race/ethnicity, socioeconomic status, and age of housing all play a role in exposure to and development of childhood lead poisoning. Additionally, nutritional status and genetics also influence lead adsorption, distribution, metabolism, and toxicity. In examining the factors that influence the risk of lead exposure, it is important to recognize that the factors all relate to and influence one another.

Lead poisoning continues to be a major environmental health concern. While ongoing research is revealing new understanding of the biological impacts and pathways of lead, much about the risks and routes of exposure is well understood and highly amenable to intervention.

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