University of Michigan and University of Hawaii researchers claim to have solved a longstanding scientific mystery of how mercury gets into open-water fish. Based on their study findings, published in the journal Nature Geoscience, they also project that mercury levels in Pacific fish will rise in the coming years.
The researchers discovered that up to 80 percent of the toxic form of mercury, methylmercury, is generated deep in the ocean, most likely by bacteria attached to sinking pieces of organic matter. Mercury found in Pacific fish near Hawaii likely traveled thousands of miles through the air before being deposited in the ocean, the team concludes, blaming industrial nations such as China and India that rely on coal-burning power plants. The U.S. Food and Drug Administration notes that large fish have the highest levels of methylmercury because they live longer and have more time to accumulate it.