BONNER — For decades, chemicals known as polychlorinated biphenyls (PCBs) have lingered in the environment, causing health problems.
Right now, the Environmental Protection Agency (EPA) is working in Western Montana to better understand where PCBs are getting into the river systems and the ripple effect those chemicals are having.
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"They are here in the river. We know they are present. It's a concern to the community, and so this is the EPA taking decisive action to start answering some of those questions," EPA Region 8 Administrator Cyrus Western told MTN.
PCBs were used in a variety of products including insulation, plastics, and industrial equipment until they were banned in 1979 after evidence showed they were toxic.
"They don't break down very quickly, so they're very persistent in nature. This is not just here in Montana. This is across the country," Western said.
In the past, PCBs have prompted fish consumption advisories and research. Yet this latest study by the EPA will focus on sediment and aquatic insects to understand watershed-wide contamination.
"The fish tissue studies have been helpful. They're great data, but we are doing something that's more broad, robust, and comprehensive and really looking at these huge watersheds to figure out, is it coming from one source? Is it coming from multiple? What stretch of river is it coming from? Are there multiple stretches?” Western said.
The EPA says that studying the macro-invertebrates can showcase more localized conditions than solely relying on fish tissue samples.
Samples will be analyzed for all 209 PCB compounds, generating approximately 27,000 new data points, and allowing EPA to evaluate both the relative magnitude of PCBs and how PCB composition varies across the river system.
A Denver-based team will be at 64 sites throughout the Blackfoot, Clark Fork, and Bitterroot rivers through September, taking sediments and two grams of the aquatic insects per site.
"We look at the water column itself. Wwe look at bugs. We look at sedimentation. Wwe kind of look at all the classic environmental indicators of the health of a water, what's in it and where it's coming from.”
Analysis is set to be done by a lab in North Carolina, where samples will be tested for all 209 PCB compounds. Results are expected next summer.
"Validating the data, processing the data so then we can turn it around and sort of actionable outcomes from the study," Western said.
The EPA believes this study will fill needed gaps in data and present a more complete picture of PCB contamination in the studied river systems.
