Schwerin Concaves Walla Walla

Schwerin Concaves, Inc., began as a wheat farming operation and added a hard chromium electroplating business that operated from the late 1970s through 2000. Combine equipment used in farming contains parts called concaves that separate wheat from chaff. Concaves were brought to the electroplating facility and covered with chrome in a process called plating that protects the equipment from wear and tear.

Contamination at the site resulted from the chromium electroplating operations. Area groundwater is used for irrigation, drinking water, and recreation. Sampling of wells within a one-mile radius of the site confirmed these wells meet state standards for drinking water. Dry Creek has not been impacted by the on-site operations.

Schwerin Concaves, Inc. (Schwerin), site owner and operator, is responsible for cleaning up the site. However, they have been unable to fully fund cleanup, so Ecology has also used state funds from the Eastern Washington Clean Sites Initiative.

Hexavalent chromium is in soil and groundwater. Elevated levels of arsenic, cadmium, iron, lead, zinc, nitrate, and sulfate are also in groundwater.

In 2000, the Washington Department of Ecology (Ecology) issued an Enforcement Order requiring Schwerin to conduct a Remedial Investigation (2005) to determine the locations and extent of contamination at the site. The order also required Schwerin to submit a Feasibility Study (2008) exploring options for cleaning up the contamination.

Following this, Ecology issued a Cleanup Action Plan (2012) using the information from the Remedial Investigation and Feasibility Study, which became final following public comment and Ecology’s response to comments. In the plan, Ecology selected the following cleanup actions:

• Treating contaminated soil and groundwater by adding reactive media that converts hexavalent chromium to trivalent chromium, a safer form. Groundwater will be monitored quarterly to track progress.
• Decontaminating and tearing down the former chrome-plating building, and disposing of wastes stored there at an approved facility.
• Placing institutional controls on the property limiting access and how the land may be used until soil and groundwater meet state standards.