I just finished going through the results of a survey of perfluorinated compounds (“PFCs”) in Washington waters that Ecology released last week. Most people are familiar with PFCs as Teflon, although they form a broader class of compounds that include the active ingredient in Scotchgard and other chemicals. There has been increasing concern regarding the presence of these compounds in the environment because they are persistent, can bioaccumulate, and have poorly quantified but possible toxic effects on humans and organisms.
Ecology conducted this study because there was a lack of data regarding PFC distribution in waters and organisms in the state. The study looked at PFCs in rivers and lakes, in wastewater treatment plant effluent, and in fish and osprey eggs. The osprey eggs were considered proxy for higher-level consumers of fish, and may provide some insight into the bioaccumulation of PFCs in Washington. Here are the main findings of the study:
Sample locations included the following areas:
The results are interesting:
- Wastewater treatment effluent had consistently higher concentrations of PFCs as compared to surface waters, ranging from 61 to 418 nanograms per liter.
- Elevated (greater than 10 nanograms per liter) concentrations were found in Lake Washington, the South Fork of the Palouse River, and West Medical Lake. All of these water bodies receive discharges from wastewater treatment plants.
- Rivers without wastewater treatment plant discharges had consistently low concentrations of PFCs. In fact, urban rivers such as the Duwamish, Nooksack, Snohomish and Puyallup Rivers had concentrations that were similar to the Entiat and Quinault Rivers, both of which were selected by Ecology as background or reference sites.
- There was no seasonal pattern of PFC concentrations. But, one type of PFC, PFHpA (perfluoroheptanoic acid), was more frequently detected in the spring than in the fall. PFHpA is a breakdown product of perfluorooctane acid (PFOA). PFOA was used in the manufacture of Teflon, and is also used in a variety of industrial and consumer products such as stain-resistant coatings, waxes, adhesives, flame-retardant foams and polishes. I wonder if the seasonal signal of PFHpA is due to environmental conditions leading to breakdown of PFOA, or if there are different seasonal sources. The study suggests the latter, noting that PFHpA is thought to be a tracer of atmospheric sources of PFCs to surface waters.
- Washington generally had PFCs’ concentrations on the low end of what is seen throughout the United States.
- Fish concentrations were highest in the Lower Columbia River, and higher in predatory fish than in bottom feeders. PFOS (perfluorooctane sulfate) was the most dominant type of PFC, which may be due to that particular PFC having a higher affinity for tissues and a greater propensity to bioaccumulate.
- Finally, the highest concentrations measured in any media in the study were in osprey eggs. These eggs primarily contained PFOS as was seen in fish, but at higher concentrations, suggesting that PFOS continues to bioaccumulate in the food chain.
What does this all mean?
Ecology’s press release accompanying this report stated that the study “affirms state’s aim to reduce perfluorinated compounds,” and mentions the development of a chemical action plan for PFCs. The study’s recommendations include:
- Conducting a food web study to accurately estimate PFOS biomagnifications.
- Developing analytical capabilities to analyze PFCs.
- Conducting a larger fish tissue study to better characterize fish tissue concentrations state-wide.
- Developing PFC criteria to address human health, wildlife, and aquatic concerns.
In other words, Ecology is going to invest resources to address PFCs in the environment. I’m not a public health expert, but it seems intuitive to me that in an era of dwindling public resources, those resources should be allocated to obtain the best bang for the buck—i.e., go after the low-hanging toxic fruit first. I’m not sure PFCs are that low-hanging toxic fruit. The difficulty is that there isn’t much solid toxicology data available for PFCs—particularly at these low levels. Minnesota has adopted a fish consumption advisory that is a sliding scale, allowing a one-meal-per-week standard if fish PFC concentrations are between 40 and 200 nanograms per gram. Only largemouth bass, Columbia River and Lake Washington fish sampled in this study would be subject to that advisory. Minnesota also has a drinking water standard of 300 nanograms per liter for PFOS and PFOA, and has assumed that concentrations of another PFC (PFBA) below 1,000 nanograms per liter are likely to not be of a concern. If those numbers were applied to the water data in this study, only the Spokane wastewater effluent sample would be of a concern, with all of the surface waters well below these thresholds.
Minnesota is due to release a comprehensive public health assessment for PFCs soon. The reason that Minnesota is paying so much attention to PFCs is because of a manufacturing facility in that state. West Virginia likewise has a manufacturing facility, and that one has been the subject of some ongoing litigation. There will be more data regarding human PFC toxicity coming out of both these states, which should be used by Washington in deciding how much resources and efforts it should allocate to PFC research. Reducing toxics is a laudable goal, and there have been many success stories over the past 50 years (DDT, lead, mercury, PCBs come to mind). We’re also dealing with plenty of persistent legacy contaminants; PCBs, for instance, are a huge driver of the Duwamish cleanup. That being said, if Ecology decides to get serious about reducing PFCs in Washington, they would have a particularly tough nut to crack. This study suggests PFCs in Washington are present in low quantities, are not from a single source, and would be difficult to treat or control. Washington is very different from Minnesota or West Virginia. This isn’t like cleaning up a discrete source or site that is bleeding contamination into the environment. What we’re likely seeing is legacy contamination from consumer products sloshing about in Washington, and because PFCs continue to be phased out (3M has already stopped producing them), I think it is unlikely that concentrations in Washington will rise above the numbers seen in this study. I’ll post more on the health studies from Minnesota as they come out, as I think these types of studies should really be considered in the policy decisions Washington makes on this issue.