Which of the following is a main chelating agent used in heavy metal toxicity?

• A. EDTA
• B. Penicillin
• C. Vitamin C
• D. Saline

Answer: (A)

Chelation therapy works by using agents that tightly bind metal ions to form stable, water-soluble complexes that are then excreted by the kidneys. The main chelating agent used in heavy metal toxicity is EDTA (ethylenediaminetetraacetic acid). EDTA has multiple donor sites that grab metal ions such as lead and other divalent metals, creating stable complexes that can be eliminated in urine. For lead poisoning, a calcium-containing form, calcium disodium EDTA, is often used to avoid depleting calcium in the body, which underscores how chelation therapy is tailored to the metal involved. The other options aren’t chelating agents: penicillin is an antibiotic, vitamin C is an antioxidant with limited metal-binding effects, and saline is just a fluid for support and does not bind metals.