Which group includes mercury, lead, and arsenic?

• A. Heavy metals
• B. Nutrients
• C. Organic solvents
• D. Gases

Answer: (A)

Mercury, lead, and arsenic are classic heavy metals. Heavy metals are metallic elements with relatively high density and atomic weight that can be toxic to living organisms even at low concentrations and tend to persist in soil, water, and air. These metals are not nutrients—essential nutrients are elements the body needs in small amounts to function properly, whereas mercury, lead, and arsenic provide no health benefit and cause harm. They aren’t organic solvents, which are carbon-based liquids used to dissolve other substances, nor are they gases in their typical environmental context. In pollution scenarios, these metals’ persistence and tendency to accumulate in ecosystems make them key contaminants to study and control.