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PCBs and Arctic Contamination


Scientists find high levels of PCB contamination in the lipids of polar bears in Arctic Norway. Many of PCB contaminates are manufactured and applied in temperate and tropical regions.

Which of the following is the BEST explanation of the high concentrations of PCB in polar bears?


The process of global distillation causes PCB to concentrate near the poles and enter the food chain.


Large ships transporting goods from the tropics to the poles release PCBs into the water.


PCBs naturally bioaccumulate in polar bears.


Polar bears drink water contaminated by PCBs that travel through oceanic currents from the topics to the poles.


Polar bears consume large quantities of phytoplankton that have absorbed high levels of PCB, thus biomagnifying in the polar bears.