Industrial processes and other human activities are responsible for approximately one-third of all current mercury emissions, according to a report published by Dartmouth researchers on Dec. 3.
The research on atmospheric and oceanic mercury may impact international environmental policy, according to Laurie Rardin, the Research Translation Coordinator for the Toxic Metals Superfund Research Program.
The extent of the research and the conclusions the report draws on mercury contamination at different points in its dissemination makes the findings unique, Dartmouth biology professor Celia Chen said.
"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 of the ocean and then up the food chain to the seafood [that] most people eat," Chen said.
This new research also contains "promising" news for the reduction of oceanic mercury levels, adding extra incentive for international policy makers to agree to a reduction treaty, according to the press release. Research models show that methylmercury concentrations in marine fish will decline roughly in proportion with decreases in all mercury inputs.
"Our model estimates show that for the North Atlantic Ocean, a 20 percent cut in the amount of mercury deposited to the ocean from the atmosphere would lead to about a 16 percent decline in mercury levels in fish," Robert P. Mason, Marine Sciences professor at the University of Connecticut, said
The research which was conducted by the Dartmouth-led Coastal and Marine Mercury Ecosystem Research Collaborative reported that mercury released into the air is currently accumulating in the oceans, affecting and contaminating seafood eaten by national and international consumers, according to the collaborative's press release.
Over the past century, mercury levels have more than doubled as a result of past and current human activities. In particular, mining, coal-burning and other industrial processes are the main contributors to mercury contamination.
The team, which consisted of 70 scientists from different institutions and disciplines, examined the effects of local mercury inputs and their impact on coastal waters in North America. The team also analyzed data on the pathways and the effects of mercury contamination in rivers across the nation, such as the Hudson River Estuary and the Gulf of Mexico.
The report investigated sources of contamination and human exposure to mercury by examining how mercury enters the ocean and transformations into the poisonous neurotoxin methylmercury, which is sometimes found in seafood.
The report's release coincides with an upcoming meeting of the United Nations Environment Programme's Intergovernmental Negotiating Committee, which will take place in Geneva, Switzerland from Jan. 13 to 18.
The committee hopes to produce a legally binding mechanism to control mercury releases and curtail its impact on the environment, according to the press release.
The research was published in the journal "Environmental Research" and in a companion report titled "Sources to Seafood: Mercury Pollution in the Marine Environment.