Scientists say mercury released into the air and then deposited into the oceans contaminates seafood that is eaten by people across the world.

Over the past century, mercury pollution in the surface ocean has more than doubled, as a result of past and present human activities such as coal burning, mining, and other industrial processes.

The report is presented through nine scientific papers in the journal Environmental Research, and in a companion report, Sources to Seafood: Mercury Pollution in the Marine Environment, by the Dartmouth-led Coastal and Marine Mercury Ecosystem Research Collaborative (C-MERC). The research also examines the effects of mercury on near-shore coastal waters.

“Despite the fact that most people’s mercury exposure is through the consumption of marine fish, this is the first time that scientists have worked together to synthesize what is known about how mercury moves from its various sources to different areas,” says Celia Y. Chen, research professor of biological sciences at Dartmouth.

Two other papers focusing on the health effects of methylmercury were published earlier this year in Environmental Health Perspectives. Methylmercury has long been known as a potent neurotoxicant, particularly as a result of acute and high level human exposures primarily through seafood consumption, but more recent research has revealed health effects at increasingly lower levels of exposure.

Chen says about a third of all mercury emissions are associated with certain industrial sources and other human actions that can be controlled. “The good news,” Chen says, “is that the science suggests that if mercury inputs are curtailed, mercury levels in ocean fish will decline and decrease the need for warnings to limit consumption of this globally important food source.”

“Our model estimates show that for the North Atlantic Ocean, a 20% cut in the amount of mercury deposited to the ocean from the atmosphere would lead to about a 16% decline in mercury levels in fish… But it is important to realize that achieving a 20% decrease in mercury deposition will require substantial cuts in current anthropogenic emissions, given the already very sizeable build-up of mercury in terrestrial environments and ocean waters,” said Robert P. Mason, Ph.D., Professor of Marine Sciences at the University of Connecticut. Mason is a lead author of the Environmental Research paper on mercury biogeochemical cycling in the ocean and a lead author of “Sources to Seafood.”

About the Coastal and Marine Mercury Ecosystem Research Collaborative (C-MERC)

In 2010, the Toxic Metals Superfund Research Program at Dartmouth College brought together an international group of scientists and policy stakeholders to establish the Coastal and Marine Mercury Ecosystem Research Collaborative (C-MERC). The goal was to review current knowledge – and knowledge gaps – relating to a global environmental health problem: mercury contamination of the world’s marine fish. C-MERC participants attended two workshops over a two-year period, and in 2012, C-MERC authors published a series of peer-reviewed papers in the journals Environmental Health Perspectives and Environmental Research that elucidated key processes related to the inputs, cycling, and uptake of mercury in marine ecosystems, effects on human health, and policy implications. For more information, please visit: www.dartmouth.edu/~toxmetal/C-MERC/index.html

The translation of this research through C-MERC and “Sources to Seafood: Mercury Pollution in the Marine Environment” was made possible by the Superfund Research Program of the National Institute of Environmental Health Sciences of the National Institutes of Health under award number P42ES007373. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the National Institutes of Health.

Further reading:
New Research Has Implications for Discussion of International Mercury Treaty