Which of the following is NOT classified as a POP?

Which of the following is NOT classified as a POP?

• A. DDT
• B. PCBs
• C. Lead
• D. Mercury

Answer: (C)

POPs are persistent organic pollutants—organic chemicals that resist degradation, linger in the environment for long periods, bioaccumulate in organisms, and cause toxic effects. DDT and PCBs are classic organic POPs because they are stable, long-lasting in ecosystems, and tend to build up in fatty tissues as they move up the food chain. Mercury is included because, in the environment, it becomes methylmercury, a highly toxic organic form that readily bioaccumulates. Lead is an inorganic heavy metal, not an organic pollutant, and while it is toxic and persistent, it’s not classified as a POP under the typical definition. Therefore, lead is not a POP.

POPs are persistent organic pollutants—organic chemicals that resist degradation, linger in the environment for long periods, bioaccumulate in organisms, and cause toxic effects. DDT and PCBs are classic organic POPs because they are stable, long-lasting in ecosystems, and tend to build up in fatty tissues as they move up the food chain. Mercury is included because, in the environment, it becomes methylmercury, a highly toxic organic form that readily bioaccumulates. Lead is an inorganic heavy metal, not an organic pollutant, and while it is toxic and persistent, it’s not classified as a POP under the typical definition. Therefore, lead is not a POP.