Which kinds of chemicals are organic contaminants?

• A. Salts and minerals
• B. Metals
• C. Herbicides and insecticides
• D. Gases

Answer: (C)

Organic contaminants are carbon-containing compounds that can enter water from living processes or human activities, such as agriculture, industry, or fuel use. Herbicides and insecticides are classic examples because they are carbon-based chemicals used to control weeds and pests; they persist in the environment and can dissolve into water, making them organic contaminants. In contrast, salts and minerals are inorganic, as are most metals and many gases; they do not have the carbon-hydrogen backbone that defines organic compounds. That linkage to carbon-based chemistry is what makes herbicides and insecticides the best example of organic contaminants in drinking water.