Moses Lake Wellfield Contamination Superfund Site | Region 10 | US EPA

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Moses Lake Wellfield Contamination Superfund Site

Site Information

Contacts:

Rod Lobos (lobos.rod@epa.gov), Project Manager, 509-376-3749

Rebecca Gerhart (gerhart.rebecca@epa.gov), Hydrogeologist, 206-553-1049

Julius Nwosu (nwosu.julius@epa.gov), Human Health Risk Assessor, 206-553-7121

Site Description:

The Moses Lake Wellfield Contamination Superfund Site is located in the City of Moses Lake in eastern Washington. The cleanup site includes parts of the former Larson Air Force Base, Grant County Airport, and some areas south of the airport. Several soil and groundwater areas at the site are contaminated with trichloroethylene (TCE) and other hazardous chemicals from the old base and aircraft industrial activities.

Most residents in Moses Lake get their drinking water from the city’s municipal system or a community system. The city and community system operators test these public wells regularly to meet safe drinking water standards. EPA and the Army Corps of Engineers test private drinking water wells in the Superfund site regularly to be sure they are safe. Several private wells within the Superfund site have whole-house filters installed to remove TCE. EPA’s long-term cleanup will restore the groundwater as a drinking water source.

Cleanup plan

EPA issued a final cleanup plan in 2008. In 2010, EPA and the Army Corps of Engineers signed a cleanup settlement with Boeing, Lockheed Martin, and the City of Moses Lake. Boeing, Lockheed Martin, and City of Moses Lake will pay $3.25 million for cleanup and the federal government will pay $55 million.

EPA has been designing and testing a treatment system to remove TCE from one of the two major groundwater contamination plumes. EPA will also start testing and designing cleanup at two contaminated soil sites.

Groundwater Treatment

Two groundwater TCE plumes begin under the former Larson Air Force Base and spread to the south. We are starting cleanup at the South Groundwater Plume since it is closer to homes with private wells and we want to clean up the source of this plume.

  • The South Groundwater Plume starts 150–250 feet underground at the South Base Dump (Site 20) and goes about 1.3 miles south-southwest. TCE levels in this plume range from 88 ppb beneath the dump and down to 5 ppb at the outer edge further south.
  • We are drilling groundwater monitoring and extraction wells to learn more about the size of the plume and the best way to clean it up. The groundwater treatment system will to pump out the groundwater and filter out the TCE. After we start the groundwater treatment system, we will keep the treatment system going until the groundwater meets EPA’s safe drinking water standard of 5 ppb TCE.

Soil Cleanup

Twelve soil sites on the former base and around the airport were used as dumps and landfills. EPA is starting the investigation and cleanup at two of the soil sites that pose the biggest environmental risk.

  • The South Base Dump (Site 20) is located in the south corner of the former base. Toxic metals like arsenic, lead, and mercury, plus gasoline, diesel, oil, PCBs, and TCE waste were probably disposed at this dump. We think that the South Groundwater Plume begins at Site 20. EPA will test the soils and groundwater, then design a cleanup to remove all the contamination that exceeds EPA’s safety levels for residential areas.
  • The Paint Hangar Leach Pit (Site 22) is located near the eastern corner of the airport. Toxic metals like lead, and toxic substances such as PCBs were detected during the initial investigation. EPA will test the soils and groundwater, then design a cleanup to remove all the contamination that exceeds EPA’s safety levels for industrial areas.

Interactive Map

The US Army Corps of Engineers provides an interactive map of the Moses Lake site. When following the Link to the Army Corp’s map, please read the CorpsMap HOW-TO/Guide on the left hand side menu. The HOW-TO/Guide will show you how to look up the current and historical groundwater sample results for the superfund site.

Key documents
Site contaminants

Soil and groundwater at the site are contaminated with trichloroethylene (TCE) and other hazardous chemicals from the old base and aircraft industrial activities. Learn more about TCE and your health.

Where to review site documents

You can review documents, fact sheets, and other written information about this site at the following locations:

  • Big Bend Community College Library
    Building 1800
    7611 Bolling Street
    Moses Lake, WA 98837
    509-793-2350
  • EPA Region 10 Superfund Records Center
    1200 Sixth Avenue, Suite 900, ECL-076
    Seattle, WA 98101
    206-553-4494 or toll-free at 1-800-424-4372 (please call for an appointment)


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