There have been growing concerns about increased mercury levels in fish which people eat. Science Daily reported on Oct. 3, 2013, "Warmer Oceans Could Raise Mercury Levels in Fish." Dartmouth researchers and their colleagues have reported rising ocean surface temperatures which are caused by climate change could make fish accumulate more mercury, and therefore increase the health risk to people who eat seafood.
Mercury which is released into the air from industrial pollution can accumulate in streams and oceans and turns into methylmercury (MeHg)in the water. Researchers studied killifish under various temperatures in the lab and in salt marsh pools in Maine. The fish in the marshes ate insects, worms and other natural food sources, while the lab fish were given mercury enriched food. The research showed the fish in warmer waters ate more and grew less, but they had higher methylmercury levels in their tissues, which suggested increases in their metabolic rate caused the increased uptake of the mercury enriched food.
Plos One has reported on this research, "Experimental and Natural Warming Elevates Mercury Concentrations in Estuarine Fish." It has been postulated that warming temperatures may increase human exposure to MeHg, which is a potent neurotoxin, by increasing MeHg production as well as its bioaccumulation and trophic transfer via marine food webs. This would result in increased human exposure to MeHg.