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The Columbia Slough runs parallel to the Columbia River and includes about 31 miles of waterway from the Willamette River to Fairview Lake. Industrial, agricultural and urban development along the Columbia Slough has resulted in contamination accumulating in the bottom of the slough. Some contaminants, including polychlorinated biphenyls (PCBs) and pesticides bioaccumulate in fish that live in the slough year-round. These fish are now unsafe to eat. In 2005, DEQ issued a cleanup plan that established a program to clean up the slough. This program includes addressing individual sites that released contamination into the slough, controlling any ongoing sources of contamination, and monitoring conditions over the long term to make sure conditions were improving.
DEQ is working with many partners to address Columbia Slough contamination including:
Fact sheet: 2012 Lower Columbia Slough Sediment Investigation
Fact sheet: 2012 Whitaker Slough Sediment Investigation
Fact sheet – 2014 Columbia Slough Sediment Investigation
Below are resources for properties conducting an upland source control evaluation:
Columbia Slough Screening Level Values
General Columbia Slough sediment SLVs
Lower Columbia Slough specific sediment SLVs
Whitaker Slough specific sediment SLVs
Columbia Slough stormwater SLVs Please use Upland Source Control Evaluation Guidance Appendix D: Non-Portland Harbor SLVs
Industrial, commercial and agricultural facilities located within the Columbia Slough Watershed have contributed to sediment contamination through historical and current wastewater discharge, stormwater runoff, bank erosion and groundwater discharge. The following fact sheet provides additional information to understand Columbia Slough Sediment Liability for owners, operators and prospective purchasers within the Columbia Slough:
Columbia Slough Sediment Cleanup: Option for Liability Release Through Cash Settlements
City of Portland Intergovernmental Agreement
Multnomah County Drainage District Memorandum of Understanding
Funds available for habitat enhancement
Habitat Enhancements Completed
Project Managers: Heidi Nelson - 503-229-6802Sarah Miller - 503-229-5040
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