Scientists at Duke University have figured out why mercury poses a bigger hazard in seafood caught in the ocean than fish caught in fresh water.
The researchers told The News & Observer of Raleigh that the chloride in ocean salt sticks to the more dangerous form of mercury, known as methyl mercury, in a way that makes it harder for sunlight to break down the metal.
The scientists found it took at least 10 times longer to break down the mercury in salt water than in fresh water.
One of the study's authors Heileen Hsu-Kim says more research needs to be done on how mercury cycles through the marine environment.
The findings were published in Nature Geoscience.