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EPA Baseline Modeling Report Released: Model Confirms Sediments Are Still Source of PCBs to the Hudson River and Will Be For Years

Release Date: 05/18/1999
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(99082) -- The U.S. Environmental Protection Agency (EPA) today released its Baseline Modeling Report, which confirms that the sediments of the Upper Hudson River will still be a source of PCBs (polychlorinated biphenyls) to the Hudson River for years into the future.
This report, which is part of Phase 2 of the overall Hudson River PCBs Reassessment, presents results and findings from the application of mathematical models to predict future levels of PCBs in Upper Hudson River sediments, water and fish. The computer model provides predictions under a "baseline" scenario, in which no action is taken to clean up the river. A number of different models were run for a 21-year forecast period beginning January 1, 1998.

The overall goal of the modeling was to develop and validate scientifically credible models that would answer the following principal questions:

! When will PCB levels in fish recover to levels that meet the criteria for protecting human health and the ecology if no action is taken to clean up the river?

! Can taking action to clean up the river significantly shorten the time required to achieve acceptable risk levels?

! Are there contaminated sediments now buried that are likely to become stirred up following a major flood, possibly resulting in increased contamination of the fish population?

The work presented in this Baseline Modeling Report provides information relevant to the first and third questions. Predictions regarding various cleanup scenarios (question 2) will be generated in the future and presented in the Feasibility Study (Phase 3 Report) due out in December 2000.

Major Findings:

The sediments in the Upper Hudson River are a major source of PCBs. Projections show that the sediments will continue to release PCBs into the water for years to come.

PCBs from sources above the Fort Edward area, such as the General Electric Hudson Falls Plant site, do not determine PCB concentrations in surface sediments in the Upper Hudson River.

Longer timeframes are predicted for fish to attain lower, more protective levels. For example, for largemouth bass above Stillwater, the model predicted that it would take a minimum of 10 years to reach the FDA level for commercial fishing and more than 21 years (the maximum forecast period) to reach the Great Lakes Sport Fishing Advisory.

A 100-year flood would not be expected to substantially increase the concentrations of PCBs in fish.

An important source of PCBs in the water is due to scour that occurs during low flow river conditions. This scour could be caused by factors such as wind-driven dispersion, the churning up of sediments by organisms and boat propellers.

The Baseline Modeling Report will undergo peer review by a panel of independent scientific experts. EPA will present the findings of the Baseline Modeling Report to the public at an informational meeting to be held this evening, Tuesday, May 18, 1999, at 7:30 p.m. at the Marriott Hotel located at 189 Wolf Road in Albany, New York. Copies of the Baseline Modeling Report will be available in the near future for public review at the information repositories established for the Hudson River PCBs Reassessment project. You can find their locations on our website at https://www.epa.gov/hudson. Public comment on this document will be accepted until June 23, 1999.