How does some of the mercury in the air end up in fish?
Once airborne mercury is deposited back to the ground, it is washed into soils, rivers, lakes and oceans. Then, through interactions with bacteria in soils, sediments and water, mercury may become chemically transformed into methylmercury. Methylmercury in fresh and salt waters can then be taken up by algae or plankton. As small fish and other animals eat plants and algae, and are in turn eaten by bigger animals (and those bigger animals are eaten by still bigger animals), methylmercury may bioaccumulate in the food chain.
