Mercury pollution in marine ecosystems from sources to seafood
Tuesday, November 5, 2013
: 4:30 PM - 4:50 PM
Mercury pollution in the surface ocean has doubled over the past century while more than 90 percent of mercury exposure in the U.S. and in many regions of the world comes from this consumption of estuarine and marine fish. The Coastal and Marine Mercury Ecosystem Research Collaborative (C-MERC), comprised of more than 70 scientists and policy experts, recently published a series of 11 papers and produced a synthesis report, “Sources to Seafood: Mercury Pollution in the Marine Environment”. The main objective of this collaborative effort was to inform policies and management actions currently under consideration at the local, national and international level to limit mercury pollution. Four major findings emerged from the C-MERC synthesis: 1. Mercury pollution contaminates commonly consumed marine fish at levels that exceed human health guidelines, and mercury pollution continues to rise. 2. Mercury pollution enters the marine environment along distinct pathways that are linked to different mercury sources. Atmospheric inputs from global sources of mercury emissions dominate in the open ocean and in coastal systems strongly influenced by ocean currents. Riverine mercury inputs dominate coastal waters that are receiving bodies of watersheds. Some coastal waters receive multiple inputs from both the atmosphere and rivers. 3. Most seafood consumers are “general consumers” whose methylmercury exposure comes from fish typically harvested from the open oceans while “local consumers” generally eat seafood from nearby coastal waters. 4. Methylmercury concentrations in marine fish will decline roughly in proportion to decreases in mercury inputs, though the timing of the response will vary. Methylmercury in open ocean fish will begin to decrease within many years to decades after emissions controls. In contrast, methylmercury in fish from coastal systems contaminated by legacy mercury may take many decades, or even centuries, to fully reflect the declines in inputs.
Environmental health sciences
Describe the different pathways along which mercury sources on land are transported to the oceans.
Differentiate between “general” and “local” seafood consumers and how different types of mercury inputs affect them.
Explain why the rate of decline in fish mercury levels will depend on the types of mercury sources that are controlled.
Presenting author's disclosure statement:
Qualified on the content I am responsible for because: I have been the principal or co-principal of multiple federally funded grants focusing on the fate of contaminants in aquatic ecosystems. Among my scientific interests has been the study of methylmercury in marine food webs leading to fish that humans consume.
Any relevant financial relationships? No
I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines,
and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed
in my presentation.