Cleaning up: Boeing Auburn groundwater contamination investigation nears completion

By Robin Harrover and Neal Hines, cleanup co-managers

Robin Harrover

Neal Hines

Before you can clean up a contaminated site, you have to know where the contamination is. Gathering the needed information and developing a report on the contamination is the first step in the cleanup process. Called the remedial investigation, it lays the foundation for all of the steps that follow.

                    

Ecology oversees a remedial investigation that The Boeing Company is conducting on a plume of groundwater contamination at the company’s Auburn facility.  The plume extends more than a mile outside Boeing’s property to the north and northwest, extending under parts of Auburn and Algona.

The plume affects parts of Algona and Auburn.
(Click to englarge.)

The groundwater at the site is contaminated with a degreaser called trichloroethene (TCE) and its breakdown products, which was used at the site to clean metal parts from the 1960s through the 1980s. The solvent likely leaked through cracks that developed over time in the concrete lining of floor pits where part cleaning occurred.

Sizing up the big plume

A reality we face with underground contamination is how difficult it can be to study. Because of this challenge, a multi-year remedial investigation is common for major cleanup sites. This site has turned out to be unusually complex and large, which adds to the study time.

It has taken 13 years, more than 275 wells, hundreds of other underground probes, and thousands of air, surface water, groundwater and soil samples to fully map out this contamination. It takes time to do this: time to determine where to drill; time to get approval to drill on private property or public rights of way; time to study samples; and, when the data show a need to continue the search, time to repeat these steps.

In 2004-05, Ecology oversaw an interim action, which is a partial cleanup conducted during the remedial investigation. Boeing treated a small area on its property that had a very high concentration of TCE that was a likely source area for the plume. The company used a process called bio-remediation in which bacteria consumed the compound and converted it to simpler and safe substances.

Robin Harrover helps people learn about the
investigation at Algona Days last summer. 

Drinking water not affected

The water in homes and businesses in the area comes from public water systems that are regularly monitored by the Washington Department of Health. The City of Auburn’s 2014 Water Quality Report provides the most recent summary of data from this monitoring, which shows no detection of chemicals of concern from the Boeing Auburn site.

The contaminated area is outside designated protection areas for public water system wells. The area’s groundwater flow carries the contaminants away from these wells.

Gathering knowledge

We now know where the contamination is located and in what concentrations. To date, the chemicals are mostly found at low levels that are not expected to pose a risk to human health and the environment.  

Neal Hines explains a map of the plume during an
availability session before an Algona City Council meeting.

This is welcome news, because as investigators traced the plume, some of it was found to lay under parts of residential and commercial areas. The presence of contamination in such areas raises understandable health and safety concerns. And, contamination in groundwater can affect property development decisions.  These highlight the importance of completing the cleanup process.

Later in 2016, we expect to formally receive and review Boeing’s report on the investigation. Ecology will ask for public comments on whether we should approve the report, or if there are unanswered questions that would require the company to do additional research and testing.

Second phase builds on first

The remedial investigation provides information needed for the next major cleanup phase, which explores options for cleaning up and remediating the groundwater. It is called the feasibility study.

Ecology works to keep people up to date, including advance notice about
investigation projects, such as this groundwater probing in Algona. 

Ecology is overseeing Boeing’s work on some preliminary work on this study. The feasibility study requires nowhere near the amount of time needed for the remedial investigation, and we expect to have it for public review and comment within months of the remedial investigation report.

The final planning step is called the cleanup action plan. Ecology will select a cleanup strategy and propose a detailed plan to carry it out. As with the other major steps, we’ll invite public review and comment on a draft plan.

Samples and the story they tell

As part of the investigation, Boeing’s environmental contractor has installed a network of more than 275 wells in Auburn and Algona. These are used to collect samples so that we can see how the plume may change over time.

Ecology also oversaw the testing of indoor air and soil air at some locations above the contaminated groundwater, and sampling and testing of surface water in yards, ponds, drainage ditches and other waterways.

With Mill Creek and its wetlands a short distance from the groundwater plume, Ecology wanted to determine whether contaminants from the plume were reaching the stream. Water samples taken from sediments in Mill Creek showed neither of the plume’s key contaminants – TCE and vinyl chloride.

To find out more:

• See our 2015 Year in Review fact sheet.
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• Attend our open house, 10 a.m. to 2 p.m. Feb. 27, Alpac Elementary School, 310 Milwaukee Blvd. N., Pacific.  It’s a drop-in event: come any time between 10 and 2. We’ll have information displays in English and Spanish, and experts available to answer questions in either language. We’re providing childcare, too.

We’re glad to answer questions any time. Please email us, or call our English and Spanish message line at 253-219-7645 and we’ll get back to you promptly.