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A new study by the US Geological Survey of mercury levels in fish has revealed widespread contamination. Every single fish tested from nearly 300 water streams in the US was found to contain mercury. More than 2/3rds of the fish tested exceeded mercury standards of concern set by the Environmental Protection Agency for fish. Previous studies have focused on lakes and reservoirs. But this study, the first of its kind, examined river beds and streams. Mercury enters the atmosphere through emissions from industrial processes, particularly coal-fired power plants. Those emissions condense into water and are absorbed by fish. Bioaccumulation of mercury compounds occurs rapidly in larger predatory fish, often consumed by humans. The USGS study found particularly high levels of mercury near coal mining areas. While that result was predictable, an additional conclusion surprised scientists: fish found in many undeveloped areas rich in pine forests and wetlands also showed substantial mercury contamination. The theory is that the natural conditions are particularly conducive to the conversion of inorganic mercury to an organic compound called Methyl mercury – this compound is far more toxic and more easily absorbed into the bodies of fish and those who eat them. Methyl mercury contamination from eating fish is considered particularly dangerous for pregnant women and infants.

GUEST: Michael Bender, Director of the Mercury Policy Project

Read the original USGS paper here: http://pubs.usgs.gov/sir/2009/5109/pdf/sir20095109.pdf

For more information visit www.mercurypolicy.org and www.zeromercury.org.