What is a key environmental issue associated with the persistence of PCBs in ecosystems?

The persistence of polychlorinated biphenyls (PCBs) in ecosystems is primarily linked to their ability to bioaccumulate in wildlife. PCBs are synthetic organic chemicals that do not easily break down in the environment, which allows them to accumulate in the fatty tissues of living organisms over time. As these chemicals move up the food chain, the concentration of PCBs can increase significantly through a process known as biomagnification.

This accumulation poses serious health risks not only to wildlife but also to humans who consume contaminated fish or other wildlife. The long-term presence of PCBs in ecosystems can lead to toxic effects, including reproductive and developmental problems, immune system dysfunction, and increased cancer risks.

In contrast, the other options do not accurately represent the characteristics of PCBs or their environmental impact. PCBs do not degrade quickly in soil; rather, they are known for their persistence. They are also not readily metabolized by organisms, which contributes to their bioaccumulation. Additionally, PCBs are hydrophobic, meaning they are not water-soluble, which further limits their ability to break down in aquatic environments and enhances their potential for accumulation in living organisms.