A new EPA study shows concentrations of toxic chemicals in fish tissue from lakes and reservoirs in nearly all 50 U.S. states, according to an agency press release. For the first time, EPA is able to estimate the percentage of lakes and reservoirs nationwide that have fish containing potentially harmful levels of chemicals such as mercury and PCBs, according to the agency.

“These results reinforce Administrator Jackson’s strong call for revitalized protection of our nation’s waterways and long-overdue action to protect the American people,” said Peter S. Silva, assistant administrator for EPA’s Office of Water. “EPA is aggressively tackling the issues the report highlights. Before the results were even finalized, the agency initiated efforts to further reduce toxic mercury pollution and strengthen enforcement of the Clean Water Act – all part of a renewed effort to protect the nation’s health and environment.”

The data showed mercury concentrations in game fish exceeding EPA’s recommended levels at 49 percent of lakes and reservoirs nationwide, and polychlorinated biphenyls (PCBs) in game fish at levels of potential concern at 17 percent of lakes and reservoirs. These findings are based on a comprehensive national study using more data on levels of contamination in fish tissue than any previous study.

Burning fossil fuels, primarily coal, accounts for nearly half of mercury air emissions caused by human activity in the U.S., and those emissions are a significant contributor to mercury in water bodies. From 1990 through 2005, emissions of mercury into the air decreased by 58 percent. EPA is committed to developing a new rule to substantially reduce mercury emissions from power plants, and the Obama Administration is actively supporting a new international agreement that will reduce mercury emissions worldwide.

The study also confirms the widespread occurrence of PCBs and dioxins in fish, illustrating the need for federal, state and local government to continue efforts to reduce the presence of these harmful chemicals in our lakes and reservoirs and ensure that fish advisory information is readily available.

It is important that women of child-bearing age and children continue to follow the advice of EPA and the Food and Drug Administration on fish consumption as it relates to mercury, according to the agency. This study is also a strong message to state and local governments to redouble their efforts in looking for opportunities to reduce mercury discharges, as well as developing fish advisories, especially to reach those in sensitive and vulnerable populations, states EPA.

Results from the four-year National Study of Chemical Residues in Lake Fish Tissue show that mercury and PCBs are widely distributed in U.S. lakes and reservoirs. Mercury and PCBs were detected in all of the fish samples collected from the nationally representative sample of 500 lakes and reservoirs in the study. Because these findings apply to fish caught in lakes and reservoirs, it is particularly important for recreational and subsistence fishers to follow their state and local fish advisories.

EPA is conducting other statistically based national aquatic surveys that include assessment of fish contamination, such as the National Rivers and Streams Assessment and the National Coastal Assessment. Sampling for the National Rivers and Streams Assessment is underway, and results from this two-year study are expected to be available in 2011. Collection of fish samples for the National Coastal Assessment will begin in 2010.