Remedial Investigation and Feasiblity Study
The U.S. Environmental Protection Agency (EPA) is currently taking the lead in assessing human health and environmental risks from sediment contamination. In 2004, EPA drafted a scoping plan for a Remedial Investigation and Feasibility Study (RI/FS). EPA’s work is authorized under federal Superfund legislation. Lake Roosevelt, however, has not been designated as a Superfund clean up site.

The EPA anticipates the RI/FS will take a minimum of four years to complete, at the end of which EPA will inform the public about:

The amount and locations of contamination,
If contaminants pose risks to human health or the environment,
If cleanup is needed, and
Cleanup options, if needed.

EPA will share information as study results are known, and each year of study work will be refined as new knowledge is obtained. In 2005, initial sediment sampling and fish tissue studies are the major actions EPA is taking.

SEDIMENT SAMPLING

In April and May of 2005, about 400 sediment samples were taken from the upper to lower reaches of Lake Roosevelt. These samples and other information will help EPA:
Further define the distribution of contaminants from north to south and bank to bank
Assess potential risk of direct contact to beach users at specific recreational areas,
Explore whether contaminated sediments are toxic to lake bottom organisms (benthic community),
Explore the depth of sediment contamination and distribution of the contaminants in the sediments (e.g, are the sediments more contaminated at or below the sediment surface, and how different are the concentrations),
Assess the potential for future movement and redistribution of sediment contamination,
Consider the effects of tributaries.

Initial results are planned to be available at the end of 2005.

Click here to enlarge map.

FISH TISSUE SAMPLING

In September/October 2005, over 100 fish tissue samples will be taken at eleven diverse locations, a combination of fish (e.g.– walleye, rainbow trout, lake whitefish and largescale suckers) will be used. Sampling will allow EPA to:

Determine concentration levels of metals, furans, dioxins and PCBs in skin, tissue and organs,
Assess potential human health risks,
Assess risks to the fish themselves, and wildlife that may consume them.
The Washington Department of Health will also review this data to assess and advise the public of potential human health risks. The Spokane and Colville tribes will use information to update fish advisories for tribal members.

Initial results are planned to be available by Spring 2006.

OTHER STUDIES

The United States Geological Survey (USGS) is also engaged in studying sediment contamination, specifically processes related to the movement of metals in the system. These studies include:

AIR MONITORING

When water levels are lowered between January and May of each year, extensive areas of contaminated sediments are exposed. Wind storms suspend dust (fine grain sediments) into the atmosphere, raising potential human health concerns.

USGS, in collaboration with the Colville Confederated Tribes and the Lake Roosevelt Water Quality Council, continues to collect air samples at three sites [Inchelium, Seven Bays, and Kettle Falls (2002)/Marcus (2003-2005)] on a regular schedule from January through June. The results show that many trace metals found in the bed sediments are also present in the air. Concentrations found do not exceed the current California EPA air quality standards for arsenic and cadmium. However, EPA outdoor air standards do not exist for most of the trace elements. Further monitoring is planned through 2006, with particular interest in changes that might occur in years when lake level draw downs are more severe.

EFFECTS OF METALS IN BED SEDIMENT ON WATER AND BIOTA

USGS, in collaboration with the National Park Service, collected sediment samples from eight sites in 2003. All eight samples were analyzed for concentrations of metals. The pore water was extracted from sediment sub-samples and also analyzed for concentrations of metals. Another sediment sub sample was exposed to water for several days and concentrations in the water determined at several time intervals to measure the uptake of metals by the water.

Finally, benthic invertebrates were exposed to one last sediment sub-sample, then the organisms were analyzed for concentrations of metals. The results of these analyses are being interpreted and will be described in a journal article in 2006.