Pacific Southwest Region
California, Nevada and Klamath Basin

Sediment Data from Klamath River Reservoirs Available

Aug 13, 2010

August, 12, 2010
Contacts: Matt Baun (530) 340-2387
Mary Simms (415) 947-4270

Sediment Data from Klamath River Reservoirs Available
Preliminary Results Suggest Human Health is Not at Risk Due to Contact With Sediment

SAN FRANCISCO -- The Interior Department’s Klamath Technical Management Team, in conjunction with the Environmental Protection Agency (EPA) today announced preliminary results of reservoir bottom sediment sampling. The results of the tests indicate human health is not at risk due to contact with the sediment and confirm the findings of previous reports regarding the low-level presence of chemicals in the sediment behind the dams including, PCBs and dioxins.

Federal environmental health officials stressed that, based on a preliminary analysis of the data, these levels indicate no current public health concerns from direct exposure to reservoir bottom sediments. Interior Secretary Ken Salazar had ordered this additional analysis of the sediments behind the Klamath River dams in order to fully assess any potential effects of releasing sediments downstream if the four dams (Iron Gate, JC Boyle, Copco 1 and Copco 2) are removed.

“Based on our initial screening of the data, these levels indicate no current public health concerns from direct exposure to reservoir sediments,” said Alexis Strauss, Director of the Water Division in EPA Region 9. “A more thorough evaluation of these data, including human health risks, will be conducted as part of the Environmental Impact Statement/Environmental Impact Report on the issue of Klamath River dam removal.”

“The data from our recent sampling is not unexpected given an earlier study in 2006 and the prevalence of these chemicals in the environment, but we wanted to make this information available as part of our commitment to an open and transparent scientific process,” stated Dennis Lynch, Program Manager for the Klamath Basin Secretarial Determination. “Further analysis will be undertaken to ensure there is a full understanding of how dam removal might affect humans and the environment if some of the sediments move downstream and some of them remain behind becoming part of the terrestrial landscape.”

-Federal and state officials noted that chemical presence in these reservoirs is more than likely a product of decades of human activity and natural processes in the Klamath Basin, which may be the reason why there was some sampling that showed chemical concentrations to be slightly greater than national and western United States “background” levels. Background is the concentration that one would expect to find in most sediment collected within the region without a known specific source for that chemical.

Scientists collected and analyzed bottom sediment samples from JC Boyle, Copco 1 and Iron Gate reservoirs.  Sampling from Copco 2 reservoir was also attempted, but there were no significant sediments from which to obtain samples. The data from this sampling effort is available on the Internet at In addition, the Department, along with appropriate federal and state agencies, will continue to reach out to local governments, residents, tribes and others in the Klamath River Basin as more information becomes available.

-- FWS --