Metal plating and metal finishing industries produce wastes that are the most toxic.

• A. Most toxic
• B. Least toxic
• C. Toxic
• D. Moderately toxic

Answer: (A)

Wastes from metal plating and finishing are asked to be categorized by how toxic they are, and the key idea is that these wastes contain substances that are extremely hazardous to both people and the environment. Plating operations use and produce heavy metals like chromium, nickel, cadmium, plus cyanide-containing complexes and acidic or basic wastes. Hexavalent chromium is a known carcinogen, cyanide is acutely toxic even in small amounts, and heavy metals persist and can bioaccumulate in organisms. Because these components create high acute and chronic hazards, plating wastes are typically considered among the most toxic waste categories. That’s why the description of “most toxic” fits best. The other levels imply lower hazard, which doesn’t accurately reflect the serious risks associated with these constituents.