Mapping and Prioritizing Contaminants in the Columbia River Basin: Innovative Techniques and Community Collaborations

Why are we studying the Columbia River?

The Columbia River Basin covers 260,000 square miles and has been home to people for more than 15,000 years (Figure 1). Today, it’s still an important resource for fishing, farming, power, recreation, and transportation. But these activities have also affected the river’s water quality. You can learn more about the EPA’s Columbia River Basin Restoration Program.

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Water quality is a complex issue (Figure 2): Agricultural runoff, industrial waste, urban activity, and other factors tend to increase the concentrations of contaminants as the river flows toward the ocean. Evaporation, attachment to sediment, ingestion by fish, and physicochemical and biological degradation tend to decrease the concentrations. Which factors dominate – those that increase or decrease the concentrations? The available literature is silent on this question; no one knows whether the concentrations of bioavailable organic compounds gradually accumulate and reach a peak at the point where the river flows into the ocean, or whether certain upstream regions exhibit higher concentrations.

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Figure 2. Potential sources of contaminants. Made with Biorender.

How are we investigating water quality?

Our team is taking several approaches (Figure 3) to better understand the river and to share practicable information with local communities.

This multi-year project involves a yearlong monitoring of contaminants in the lower Columbia River through monthly passive sampling conducted across approximately 170 river miles. Samples are analyzed for PFAS and hundreds of known and previously unrecognized emerging organic chemicals using advanced targeted and non-targeted analytical methods. These data are used to characterize spatial and temporal trends, identify contaminant pathways, and support predictive risk modeling.

Potential biological impacts are assessed using zebrafish embryo and human cell-based assays to evaluate relative toxicity and biological activity. The project places strong emphasis on community engagement through collaboration with a multi-partner advisory board and public outreach efforts, including webinars, newsletters, infographics, and partner briefings.

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Figure 3. Study Design. Made with Biorender.

Sampling Locations and Samples Collected

Using passive sampling devices, we can sample the water continuously for one year. Lead by Food Safety and Environmental Stewardship Program Director, Dr. Kim Anderson, passive sampling devices are placed at 10 key locations along the river (Figure 4):

• Above and below The Dalles Dam (Sites 1 and 2)
• Above and below Bonneville Dam (Sites 3 and 4)
• Upstream of Portland metro area (Site 5)
• Above and below the Portland Harbor Superfund Site (Sites 6 and 8)
• At the junction with the Willamette River (Site 7)
• Confluence of the Cowlitz River (Site 9)
• The mouth of the Columbia (Site 10)

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Figure 4. Sampling locations along the Lower Columbia River.

These sites allow us to probe the influence of dams, urban areas, and river confluences. Dams exert a commanding influence on the flows of river water and its contaminants. Similarly, we have chosen locations above and below the Portland Harbor Superfund Site to assess the impact of industry and urban development.

Identifying and Quantifying Contaminants

Three teams will work to identify and quantify contaminants collected by the passive sampling devices.

• Dr. Kim Anderson will detect polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), flame retardants, dibenzofurans, pesticides, personal care products, pharmaceuticals, and other organic chemicals.
• Dr. Serhan Mermer will measure concentrations of 40 per- and polyfluoroalkyl substances (PFAS) by liquid chromatography-mass spectrometry.
• Dr. Manuel Garcia-Jaramillo will conduct non-targeted analyses (NTA) and suspect screening analysis (SSA) of the passive sampling extracts to identify unknown compounds or potentially compounds not yet known to exist on the river.

Toxicity Testing and Effects Directed Analysis

Dr. Robyn Tanguay will test the relative toxicity of the passive sampling extracts at the AAALAC accredited Sinnhuber Aquatic Research Laboratory (SARL). SARL is the world’s largest zebrafish aquatic toxicology facility. To read more about relative toxicity testing of PAH mixtures, see the Superfund Research Center webpage.

Dr. Garcia-Jaramillo will work with Dr. Tanguay to find out which chemicals collected from the river water could be harmful. They will use a process called effects-directed analysis (EDA). In EDA, the water samples are broken into smaller parts and tested for their effects on living things, like in bioassays and zebrafish studies, before being checked with chemical analysis.

Modelling Contaminant Sources

Using the chemical composition data collected by the Mermer, Anderson, and Garcia-Jaramillo labs, Dr. Gerrad Jones will work to identify the primary sources and processes ( e.g., agricultural runoff, snowmelt, natural products produced by local environment) that influence the composition of the surface water. 

Predictive Model for Prioritized Contaminants

Dr. Stephen Good will use satellite data and project results to build computer models that predict where target contaminants are found in the Lower Columbia River and how concentrated they are. He will test different machine learning methods to see which ones can most accurately match satellite data with chemical measurements, and he will also look at how climate factors like temperature and river flow affect the results.

Outreach and Education

Science works best when communities are involved, so we have created an Advisory Board made up of local community members and subject experts to review our study and share results. The Advisory Board will help make sure our project focuses on community health, resilience, sustainability, water quality, and fair treatment in exposure to water contaminants. Following EPA’s public participation model, we will keep communities informed, listen to their input, work closely with our Advisory Board, and empower people living near the Lower Columbia River.

Funding Acknowledgment

This publication was developed under Assistance Agreement No. 02J83901-0 awarded by the U.S. Environmental Protection Agency. It has not been formally reviewed by EPA. The views expressed in this document are solely those of Oregon State University and EPA does not endorse any products or commercial services mentioned in this publication.