Environment and Health: Heavy Metal Toxicity

Heavy metals are naturally occurring, high-density elements such as arsenic, cadmium, chromium, lead, and mercury. These five metals are the most common causes of heavy metal poisonings. Zinc is also of concern. Heavy metals are widely distributed in the environment and can be toxic even at low concentrations. Exposure commonly occurs via ingestion, inhalation, or skin absorption. Occupational exposures are common and can occur in mining, refining, and smelting operations. Lead exposure disproportionately affects lower-income, inner-city communities due to older housing stock and historical industrial contamination. Adverse health effects of exposure to heavy metals vary by type and form of metal, exposure factors (eg, route, dose, duration), and individual patient characteristics (eg, age, sex). Toxicity management includes supportive treatments, decontamination, chelation, and/or surgery depending on the clinical situation and metal involved. For some types of heavy metal toxicity, there are no definitive treatments. Acute poisoning with arsenic and chromium can be fatal. Pregnant and breastfeeding patients and young children are particularly vulnerable to heavy metal exposure due to its effects on fetal and child development. In cases of suspected exposure, patients should be evaluated with a thorough history, including detailed occupational and social histories, and a physical examination, with laboratory tests and imaging as needed.