What are persistent organic pollutants (POPs), and why are they a concern for water quality?

• A. Sodium chloride is an example of POPs.
• B. Inorganic metals that dissolve quickly are POPs.
• C. Persistent organic pollutants are long-lasting organic chemicals that resist degradation, bioaccumulate, and harm wildlife and humans (examples include PCBs, DDT, and dioxins).
• D. Natural organic compounds that degrade rapidly are POPs.

Answer: (C)

Persistent organic pollutants are long-lasting organic chemicals that resist degradation, bioaccumulate in organisms, and can harm wildlife and human health. Because they persist in water, sediments, and even air for long periods and can travel long distances, they create chronic water quality problems far from where they were released. Their tendency to accumulate in fatty tissues means they concentrate up the food chain, so top predators and people who eat fish can be exposed to higher levels even if local emissions stop. They are toxic at low concentrations and can disrupt hormones, reproduction, and development, among other effects. This combination makes water quality monitoring challenging and requires advanced treatment methods to remove them from drinking water and wastewater. Examples like PCBs, DDT, and dioxins illustrate the traits of persistence, bioaccumulation, and harm. Other options don’t fit because sodium chloride is a simple, non-persistent salt; inorganic metals that dissolve quickly aren’t persistent organic pollutants; and natural organic compounds that degrade rapidly don’t have the lasting, bioaccumulative, and toxic profile of POPs.