Historically polychlorinated biphenyls (PCBs) have been used in various industrial applications such as electrical equipment and hydraulic fluids. PCBs are highly stable organic compounds that persist in the environment for a long time. When released into water bodies, PCBs are absorbed by plankton and other small aquatic organisms. As larger predators consume these contaminated organisms, they accumulate higher concentrations of PCBs in their bodies. This process continues as predators higher up the food chain consume contaminated prey, leading to an increase in concentration of the PCBs. Consequently, top predators like birds of prey and marine mammals end up with dangerously high levels of PCBs in their tissues, which can impair their immune systems, reproductive abilities, and overall health. This underscores the importance of proper waste management and regulations to prevent further contamination of ecosystems and protect biodiversity.