Several chemical elements are toxic to humans even at low exposures: lead, mercury, arsenic, cadmium, hexavalent chromium, thallium and beryllium are major examples. Other elements can be harmful in excess or certain forms — nickel, manganese, selenium, uranium and antimony — while essential metals like iron, copper and zinc become toxic at high doses. Toxicity depends on dose, chemical form and exposure route.

Common toxic elements measured in blood include lead, mercury, arsenic and cadmium. Other metals sometimes tested are chromium, nickel and aluminum; manganese and thallium may also be assessed in specific exposures. Blood tests evaluate recent or ongoing exposure and help guide treatment; interpretation depends on the element, concentration, timing, and source of exposure.

Elements 22 test is a laboratory panel that measures concentrations of 22 essential minerals and toxic metals (often by ICP‑MS) in blood, urine or hair. It helps assess nutritional mineral status and environmental or occupational heavy‑metal exposure, guiding detection of deficiencies, overloads or toxicity. Results need clinical interpretation alongside symptoms and may prompt dietary changes, supplements or further evaluation.

A toxic elements test detects and measures metals and metalloids (lead, mercury, arsenic, cadmium, etc.) in blood, urine, or hair to diagnose acute or chronic poisoning, identify occupational or environmental exposure sources, evaluate unexplained neurological, gastrointestinal, renal, or hematologic symptoms, monitor treatment effectiveness, and screen at‑risk individuals such as children and pregnant people to prevent lasting developmental or systemic harm.

Elementally, polonium (especially polonium-210) is among the most toxic to humans because tiny amounts deliver lethal alpha radiation internally. Among non‑radioactive elements, arsenic, mercury and lead are the most harmful — causing acute poisoning, neurological damage and chronic disease at relatively low exposures. Acute harm depends on chemical form, dose and route of exposure.

Commonly recognized heavy metals include arsenic, lead, mercury, cadmium, chromium, nickel, zinc, copper, iron, manganese, cobalt, molybdenum, vanadium, tin, antimony, bismuth, thallium, uranium, silver, gold, platinum, palladium and aluminum. Many occur naturally but can be toxic at elevated exposures, bioaccumulate in tissues and food chains, and pose human and ecological health risks; monitoring and reducing exposure are important public health measures.