Anacortes Former Water Treatment Plant

Last Updated:  July 2021

Response to Comments

Response to Comments Summary (July 2021)

Final Documents

Final Cleanup Action Plan (July 2021) Final Consent Decree (in process...)

Fact Sheet (June 2021)

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Engineering Design Begins for Cleanup Implementation
Ecology conducted a 30-day public comment (June 1 - 30, 2021) on a draft Cleanup Action Plan and associated documents for the Anacortes Former Water Treatment Plant (Plant) cleanup site (Site).  Ecology held an online public meeting on June 7, 2021 to provide more information and answer questions.

Ecology has reviewed and considered the public comment received on the Cleanup Action Plan, Consent Decree, and SEPA Determination. Based on Ecology’s evaluation of the comment, no changes were necessary in the documents, and they are being finalized. (Download the Response to Comments Summary)

Work will begin on the engineering design. See graphic below and visit Ecology’s cleanup process webpage to learn more about Washington’s formal cleanup process

The Site is located next to the Skagit River in Mount Vernon (see map) and is next to the current water treatment plant, which provides the drinking water for the City of Anacortes (City) and surrounding communities. 


Drinking water information

For more information on the City’s drinking water monitoring, see below and visit www.safeandcleanwater.com. 

The Model Toxics Control Act (MTCA) is Washington’s environmental cleanup law. It provides requirements for contaminated site cleanup and sets standards that protect human health and the environment. Ecology enacts the MTCA and oversees cleanups. The MTCA site cleanup process is completed in steps (see graphic below) over a variable timeline. 

• June 1 - 30, 2021:  Held 30-day public comment period.
• June 7, 2021:  Held an online public meeting. (Download presentation PDF)
• Summer 2021:  Finalize the Cleanup Action Plan and associated documents. Ecology will review and consider all comments received and respond accordingly.
• 2021-2022: Complete design of the cleanup and implement the cleanup action.

Current Anacortes Former Water Treatment Plant cleanup site Public Participation Plan 

This plan includes information for the public regarding opportunities to get involved in the Site cleanup process. The outreach activities and mechanisms presented reflect Ecology’s current plans for keeping the public informed and for receiving information and comments from the public.

The City, with Ecology oversight, completed an environmental study (Remedial Investigation/Feasibility Study) of the Site and assessed cleanup options. Based on this work, which was approved in May 2020, Ecology has prepared a Cleanup Action Plan to address soil contamination at the Site. 

Removal and Off-Site Disposal

All soils exceeding the MTCA Method A Unrestricted Land Use cleanup level for PCBs (1 mg/kg) will be excavated and disposed off-Site in a permitted landfill.  Structures that represent a source of PCB contamination to shallow soil (the Sedimentation and Filtration Basins) will be demolished and also properly disposed off-Site.

For more information on cleanup standards download the fact sheet: “Focus on: Washington’s Environmental Cleanup Law”

PCBs were found in the exterior wall coatings of the Sedimentation and Filtration basins and adjacent soils (see “Soil Removal” in figure ). The thin veneer coating on the exterior of the concrete basin walls of the Sedimentation and Filtration Basins is the source of localized PCB contamination in shallow soils. PCBs in the coatings were also absorbed into the top 1- to 3- centimeters (cm) of the concrete walls, which are just over 20 cm thick. The figure to the left shows the typical PCB concentrations in the coating and adjacent concrete of Site structures. 

No contamination was found in the Sedimentation and Filtration basin interior walls.

In 2015, while conducting a demolition and hazardous materials assessment of the decommissioned Site, samples of building materials and soil were found to contain polychlorinated biphenyls (PCBs). The Remedial Investigation and the 2015 Hazardous Materials Assessment found:

• Groundwater and surface water:  The field sampling confirmed that there was no indication of PCBs released to groundwater or surface water. 
• Building Materials:  PCBs were found in the exterior coatings of the Sedimentation and Filtration Basins and some of the building materials of the Administration Building. This is the source of PCBs in soil at the property.
• Soil:  PCBs were only found in shallow soils between 0 to 12 inches below ground surface on a limited portion immediately next to Site structures. PCBs were detected in shallow soils at concentrations that exceed the residential/unrestricted land use cleanup level (1 milligram per kilogram [mg/kg]) under MTCA. These shallow soils will be removed and disposed off-Site in a permitted landfill. See figures on page 3 of the Fact Sheet.  

For more information on cleanup standards download the fact sheet: “Focus on: Washington’s Environmental Cleanup Law”

BACKGROUND AND LOCATION
The Site is located at 14489 River Bend Road in Mount Vernon. The former plant was constructed on the property between 1969 and 1970 to treat water from the Skagit River prior to transfer to the City of Anacortes municipal water storage and distribution network. The former plant's structures were decommissioned in 2013 when the new water treatment plant (built on a different part of the same property) became active.

Based on the Remedial Investigation, the Site consists of these decommissioned structures and the adjacent contaminated soils (click on site layout to the left for larger image):

• Filtration Basin:  a nearly 8,000 square foot concrete basin that used anthracite,  sand, and gravel for water purification.

• Sedimentation Basin:  an over 19,000 square foot concrete basin that featured  gravity flow through the system into clean water overflow troughs for settled  particulate collection.

The City conducted regular sampling of drinking water produced from the former Plant beginning in 1976 and continuing throughout operation. No samples of drinking water tested for PCBs ever contained detectable concentrations of PCBs.

In 2017, the City conducted an evaluation of potential human health risks associated with contamination at the Site and determined that no adverse health effects are likely to have occurred to customers, workers, or water plant visitors as a result of PCBs at the former Plant. 

For more information, to sign-up for updates, and to view the  Human Health Assessment go to:  www.safeandcleanwater.com

Contact the City of Anacortes:   info@safeandcleanwater.com 360-299-1950

• Anacortes Former Water Treatment Plant – Human Health Risk Assessment (March 2017)
• Anacortes Former Water Treatment Plant – Site Hazard Assessment (August 2018)
• Anacortes Former Water Treatment Plant - Fact Sheet (April 2019)
• Anacortes Former Water Treatment Plant – Online Public Meeting – March 23, 2020 (View 35 min. YouTube recording)
• Anacortes Former Water Treatment Plant – Final Remedial Investigation/Feasibility Study (May 2020)