Which characteristic of PCBs contributes to their status as an environmental and health hazard?

The characteristic of chemical stability is a significant factor contributing to the environmental and health hazards posed by polychlorinated biphenyls (PCBs). PCBs are resistant to degradation in the environment, which means they persist for long periods without breaking down. This stability allows them to accumulate in the food chain and in the tissues of living organisms. Their persistence increases exposure risk, as they can bioaccumulate in fatty tissues, resulting in higher concentrations in organisms at higher trophic levels.

Further, the stability of PCBs can lead to long-lasting contaminations of soil, water, and air, posing continuous risks to both environmental health and human safety. This characteristic, combined with their potential to cause adverse health effects—including hormonal disruptions, immune system impairments, and carcinogenic effects—highlights why their stability is a key factor in their classification as environmental and health hazards.

Other characteristics, while notable, do not directly address their persistence and long-term impact as effectively as chemical stability does in this context.