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An Expert Explains Why 'Dark Waters' Is a Warning for Us All

tap water
December 13, 2019

By Debbie Koenig

The film Dark Waters is a real-life horror story. Based on actual events, it shows how a determined attorney took on chemical giant DuPont, proving that they dumped a substance the company knew was toxic into the water supply of a small town in West Virginia. That chemical, PFOA, is just one member of a class known as per- and polyfluoroalkyl substances, or PFAS. These chemicals don’t break down in the environment, or in your body. And as the movie shows, they’re already in the blood of 99% of Americans.

WebMD spoke with Alexis Temkin, Ph.D., a toxicologist with the Environmental Working Group, about the dangers posed by PFAS. Our interview has been edited for length and clarity.

WebMD: Give me a layman’s explanation of PFAS. What are they, and why should we worry about them?

Temkin: PFAS are a group of man-made synthetic chemicals primarily used for water and stain repellents, in a variety of consumer products. The most well-known are used to manufacture products like nonstick pans and stain-repellent carpeting. They can also be found in AFFF, a firefighting foam, which is often used on military bases and for firefighting training purposes. Due to these uses they can wind up in drinking water and contaminating the environment.

What’s unique about this class of chemicals is that they’re extremely resistant to degradation. Once they’re in the environment they won’t break down, so they’re often referred to as “forever chemicals.” We also know that they’ve been detected in the blood of nearly everyone. Once they’re in the body they take a very long time to be eliminated, and with more exposure they can build up over time.

WebMD: How does exposure affect a person’s health?

Temkin: A lot of what we know about the health effects of PFAS came from the C8 Science Panel in Parkersburg, WV, which studied the community [depicted in Dark Waters] that had their drinking water contaminated with PFOA for decades. That panel studied individuals in the community, looking at blood levels and disease incidence, and found a probable link with six different diseases: high cholesterol, ulcerative colitis, thyroid disease, testicular and kidney cancer, and pre-eclampsia. 

As more people have studied these chemicals, we’re finding that even lower levels of exposure can be associated with harmful effects. With children, lower level exposure has been associated with reduced effectiveness of vaccines, and we’ve seen other health effects like infertility, low birth weight and trouble breastfeeding, and endocrine disruption. Currently based on some estimates, the safe level is around 0.1 parts per trillion in drinking water. We’ve seen that number just keep decreasing as we learn more about the toxins.

WebMD: Is there any treatment once you’ve been exposed?

Temkin: No. It’s really an issue of preventing further exposure. If you look at biomonitoring studies done by the CDC, you can detect not just one PFAS but several different chemicals in around 99% of the population. It’s very likely that everyone is exposed in some way. We also know that you can detect PFAS in cord blood—even babies, before they’re born, are getting exposed.

WebMD: It’s well-established that PFAS are dangerous. Why do you think they’re they still being used?

Temkin: The manufacturers knew for decades that these chemicals were toxic, and this comes out in the movie, with litigation around contamination of the drinking water in a community. Since then there’s been research by EPA scientists and academic scientists which has reinforced those findings, and found that even low levels of exposure are very toxic and have a variety of health effects—yet there’s been no regulation from the federal level to set a limit of how much PFAS can be in drinking water, or even knowing which companies are manufacturing them and where and when they might be discharging them. It’s a failure in terms of chemical regulation at the federal level.

WebMD: According to the EPA, PFAS can be found in numerous household products, not to mention contaminated drinking water. How can we avoid further exposure?

Temkin: PFAS are in a variety of products, in particular food packaging—a new study came out recently that looked at the amount of fast food or microwave popcorn people ate and levels of PFAS in their blood. The more they ate, the higher their levels.

We recommend avoiding fast food and food packaging as much as possible, opting for more fresh foods and home cooked meals. Similarly, using stainless steel and cast-iron pans for cooking, and avoiding microwave popcorn—PFAS can be in the lining of the bags. Also avoiding stain-repellent textiles and fabrics, and foregoing added stain repellents on new carpets.

Our guidelines are the best thing we can offer right now, in terms of knowing where PFAS is used and trying to make choices about stain repellants or types of cookware, and learning about drinking water contamination. We have an interactive EWG map where we regularly update known sites, to track contamination in the U.S.

WebMD: What should readers do if they suspect they’ve had a larger-than-average exposure?

Temkin: The best thing to do is to focus on preventing future exposures. Also, this is an issue of federal regulation—there are bills coming up in Congress. People can work with their legislators, telling them why this is an important issue and something they should be working on.

What we’re seeing with our research is, the more you look for PFAS the more you find them. To address the issue, we need really good monitoring, really good detection in drinking water so we know where the contamination is happening. And classification of these chemicals as hazardous substances—we have to know where they’re being made and where they’re being released. And regulated in some way.

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