Forever Chemicals on the Ski Trail: A Conversation with Gail Carlson

Snow sampling

Fluorinated glide wax is used in winter sports to increase a skier or snowboarder’s speed by reducing friction. Commonly used in Nordic ski racing since the 1980s, this wax produces speed with a key chemical ingredient known as per- and polyfluoroalkyl substances, or PFAS. PFAS are called “forever chemicals” because they persist in landscapes, food chains, and human bodies. Dr. Gail Carlson’s new study in Chemosphere, co-authored with her student and Nordic ski racer, Skylar Tupper, is the first to evaluate the occurrence, persistence, and mobility of PFAS at an area used for ski racing in the United States.

Dr. Gail Carlson is the Director of the Buck Lab for Climate and Environment and a professor in the Environmental Studies Program at Colby College. In this conversation, we discuss the impacts of PFAS use in Nordic skiing, new polices banning them, the science gap and a regulation gap around these chemicals, and how Dr. Carlson’s research and teaching informs her environmental advocacy.

Stream or download our conversation here.

Interview Highlights

This interview has been edited for length and clarity.

Clare Sullivan: Cross-country skiing or Nordic skiing is having a bit of a moment this year, as is the case with many other types of outdoor recreation during the pandemic. Participation numbers are way up, and in Wisconsin, we’ve seen record numbers of skiers on the trails. Cross-country skiing is sometimes called a silent sport, and I think a lot of skiers think about it as a relatively low impact form of outdoor recreation and a way to spend time in nature. You have a really interesting recent study that focused on a very specific and lasting impact from cross-country skiing based on ski wax. What brought you to this topic?

Gail Carlson: I have taught a course in the Environmental Studies program at Colby College for many years called The Environment in Human Health, which looks into the health impacts of toxic chemicals in the environment including the chemicals that are in fluoro ski waxes, the so-called “forever chemicals” or PFAS (per- and polyfluoroalkyl substances) chemicals. Over the years I’ve had a number of students from the Colby Nordic ski team in my class, and finally one of those students took me up on an offer to go and actually do some environmental testing at our local cross-country ski place, which is this beautiful place called Quarry Road Trails.

Cross country skier
Cross-country skier at Quarry Road Trails. Photo by Knack Factory for Colby College.

Also, my son was a competitive middle school and high school Nordic skier here in central Maine and I was always concerned because his team and the coaches would be in the waxing shed putting fluoro waxes on the skis. So, this has been an issue that’s been really important to me for a long time.

And thinking about cross-country skiing as a sport, you’re right: it’s silent, it’s beautiful, it gets you out in nature in the winter, it’s such a great aerobic sport. But it was having this impact on some of these beautiful places where we go skiing, and that was something I really wanted to pursue.

CS: These waxes are used throughout winter sports in downhill skiing and snowboarding and cross-country skiing. Can you talk about the way a cross-country skier will use a fluoro-based wax?

GC: There are many types of ski waxes and they can be made out of different chemical components, but the fluorinated chemicals are very slippery chemicals that will basically offer some level of water resistance to whatever they’re added to. It keeps the melted snow off the bottom of the ski and allows for a very fast race. But the industry and competitive sports are really moving away from fluoro waxes, which is a good part of this particular story.

The properties that make PFAS chemicals durable stain- and water-resistant treatments make them very dangerous environmental contaminants.

PFAS chemicals are a large family of chemicals; there’s over 4,000 of them, many of which we know very little about. They tend to have the property of conferring water resistance, grease resistance, stain resistance, and non-stick properties to whatever they’re added to. Their use in ski wax is just one of those types of applications. You also see PFAS chemicals in things like Teflon and other non-stick coatings on pans, Gore-Tex treatments of outdoor outerwear, and stain resistant treatments of things like carpets or furniture upholstery. And there are many industrial applications as well.

CS: So PFAS are chemicals that we’re interacting with throughout our everyday lives. They’re in our consumer products, our houses, and our industrial processes.

GC: Yes, and they’re in our drinking water and in our food supply, because they have been used so widely in industry without controls on emissions into the environment, and they travel pretty widely so you see contamination pretty far from sites of production. The thing that is really dangerous about PFAS is how persistent they are in the environment. They have very long half-lives, on the order of decades or more, and precisely the properties that make them durable stain or water-resistant treatments make them very dangerous as environmental contaminants.

It’s basically impossible to regulate them because they move through the environment very readily and are so extraordinarily persistent. We interact with them because they are bioaccumulative, which means that they build up in living organisms including plants, animals, and people. The Centers for Disease Control and Prevention (CDC) conducts regular body burden studies of Americans, and they’ve shown that every American basically has measurable levels of PFAS in their blood. The other property that’s particularly dangerous is how toxic they are; they are linked to all kinds of adverse health impacts. So, you have this triple whammy of persistence, bioaccumulation, and toxicity that makes them really dangerous.

CS: Your study takes this context of ski wax use and looks at two big questions. The first is, how much of those fluorocarbons do you see in the snow in a couple different locations immediately after a race. Then you come back to the site several months later after the snow is gone to get at this question of persistence and mobilityto look at how these chemicals are persisting in the soil after the snow is gone and how they’ve moved through waterways. Could talk about your study site and how you developed your methods to be applicable to this very specific land use of Nordic ski racing?

Cross country skiers at the start of the American Birkebeiner Race
Cross country skiers line up at the start of the Korteloppet race in Cable, Wisconsin. Photo by Clare Sullivan, 2019.

GC: The site was a logical choice because it is the place in our town of Waterville, Maine, where a lot of recreational and competitive Nordic skiing happens. One of the members of the Colby Nordic ski team in my class, Skyler Tupper, was interested in doing this testing. She raced in the race that immediately preceded our sample collecting, and then we went around and collected soil and water samples. We found extraordinary contamination of snow at the start line of the race when the skiers are on their freshly waxed skis and rubbing them in the snow. That contamination doesn’t just affect these collegiate racers, it affects everyone, because the chemicals are in the snow until it melts and then they either move with meltwater through the environment or they may deposit in the soil underneath.

This was really the first time that an American place that does Nordic skiing was tested, and we found such extraordinary contamination at the start line that even the laboratory that did the testing for us was surprised at how high the levels of fluorinated chemicals were. When we tested snow that was farther along the race course, a few kilometers in, we found much lower levels so we could show that most of the ski wax appears to be rubbing off the skis in the early part of the race.  

We also were interested in the question of broader contamination of the landscape, so we had to wait until the ground thawed and the snow stopped, which is pretty late here in central Maine. In May, we went out and collected soil at the same sites where we had collected snow and were able to determine that where there was the most snow contamination, we could also detect soil contamination. One of the most worrying things that we found is that there’s some shallow groundwater out there and we found quite high levels of some of the shorter chain chemicals that move pretty readily through soil and water, so that’s something that I’m really interested in following up with.

CS: Do we have a good understanding of this property of toxicity in the environment and in human bodies?

GC: With respect to PFAS, we have both a science gap and a regulation gap—there’s so much that we don’t know about the environmental properties and toxicity of PFAS chemicals and there are over 4,000 of them. We tend to under study the health impacts of chemicals partly because our regulatory mechanism, which is the Toxic Substances Control Act in the United States, does not require safety testing or toxicity testing for most chemicals. Most of the work on the toxicity of these chemicals has come from highly exposed populations that lived adjacent to manufacturing centers.

The biggest reason to do this type of research is to show that contamination occursand that we need to figure out how to stop it.

The best evidence we have for health impacts comes from something called the C8 Health Study in the area around a DuPont manufacturing plant in West Virginia that was making Teflon and the precursor chemical for Teflon, which is PFOA, and also known as C8. In that area there were 70,000 Americans who had contaminated drinking water, and they linked exposure to PFOA to a number of health outcomes including several forms of cancer and ulcerative colitis, and high cholesterol and preeclampsia in pregnant women. Subsequent studies have linked it to other forms of hormonal disruptions, especially in children. Recent headlines have emerged in the context of the pandemic, because it turns out people with high levels of PFAS in their blood have immune suppression, which could make them more susceptible to COVID-19. We’re starting to learn more and more about the health effects of PFAS but there just aren’t enough people or resources to look individually at 4,000 chemicals and figure out what they’re doing in the human body, so we have a big gap.

To date we’ve also had this regulatory gap where we basically allowed people to manufacture, use, and dispose of PFAS pretty much without much regulation for decades, and now we’re faced with a situation again where it’s almost unregulatable because it’s everywhere. But U.S. states are stepping up and starting to do some things, as well as the European Union and the international community in the context of an international treaty that we have on persistent organic pollutants called the Stockholm Convention. But only two PFAS chemicals are included there and there’s so many more that need to be regulated.

CS: Rachel Carson’s Silent Spring was really a call for us to better understand how chemicals bioaccumulate and how they move throughout the landscape. We understand a little about the exposure of just a few of these chemicals, but is there much work on the mobility side of understanding how these chemicals move through different ecological systems, soils, and waterways?

A woman with brunette hair and glasses in front of a bookshelf. Headshot of Gail Carlson.
Dr. Gail Carlson, Assistant Professor in the Environmental Studies Program at Colby College. Photo courtesy of Carlson.

GC: What we’re starting to realize is that PFAS chemicals are extraordinarily mobile in the environment. They can really move quite readily through soil and water, and many of them also can move through the air and be deposited hundreds, even thousands of miles away from where they’re produced. From a regulatory standpoint, especially in Europe, a chemical being designated as a persistent, bioaccumulative, and toxic substance is enough of a trigger to start regulating it, and they’re adding mobility to that designation. So, if something is extraordinarily mobile through the environment it may actually trigger regulation even if we don’t know very much about its toxicity.

It’s very different in the U.S. at the federal level, where our chemicals regulation is pretty weak. Fortunately, many states have stepped up and filled in that regulatory gap. For example, I’m here in the state of Maine, and two years ago Maine’s legislature banned PFAS in food packaging materials and banned them all as a class, which is something that would never happen at the federal level.

CS: Chemical policy sounds like it’s happening in very different ways at different scales, where international policy is being driven by different things than U.S. federal policy and state policy is again different. Where do you see your science fitting in that fragmented policy landscape?

GC: The biggest reason to do this type of research is to show that this contamination occursand that we need to figure out how to stop it. It’s really easy to prevent future contamination by just stopping the use of these fluoro waxes, which is fortunate for this particular source of exposure and contamination. When we’re talking at a large scale about the production of consumer products and industrial processes, that’s a much bigger issue. Even though regulating fluoro ski waxes is not going to drastically reduce the amount of global PFAS out there, it’s an important example that we can use to really spur on regulatory action and some of these industrial responses, like the ski wax industry saying no more fluoro waxes.

When you’re trying to improve the system, I find that you have to start with your corner of the world.

From a teaching standpoint, it’s really nice to be doing this research and studying the environment in a state like Maine, where there is so much environmental policymaking going on and some really innovative advances in safer chemicals policy. I spend time at the state capitol each legislative session testifying in support of safer chemicals policies as an expert scientist, and I encourage my students to also get involved. Each time I’m at a public hearing at least one of my students is there too and oftentimes they’ll testify, and you can just see the legislators respond to the testimony of young people. A really great part of this whole process is to focus on the science but also to be able to focus on the policymaking.

CS: It’s exciting to see scientific work so quickly translated into clear political actions like serving as an expert witness, visiting your legislature, and advocating for policies. It’s a hopeful piece of a story about high-risk persistent chemicals.

GC: If you’re always just telling the bad stories of contamination, stories of climate change or stories of biodiversity loss, that really has a psychological effect on students. It’s important for them to understand the problems and I incorporate a lot of science into my classes, but I think it’s also important for them to know that they can be part of the solution. That’s what’s really rewarding about teaching in an applied discipline like this.

When you’re thinking about making change and trying to improve the system, I find that you have to start with your corner of the world or one set of chemicals or one set of impacts, and just try to make a difference and hope that snowballs into more action. If you’re interested to get involved in public campaigns to try to phase out these chemicals, see what’s happening in your state. Is there an environmental group or a public health organization that’s working on this, or legislative initiatives going on? When we get involved collectively, we can really put a lot of pressure on decision makers to ultimately phase out these chemicals.


Featured image: Snow sampling at Quarry Road Trails. Research conducted by Skylar Tupper and Gail Carlson. Photo by Knack Factory for Colby College.

Podcast music: “Gloves” by Julian Lynch. Used with permission.

Gail Carlson is the Director of the Buck Lab for Climate and Environment and an assistant professor in the Environmental Studies Program at Colby College. She was born and raised in Madison, Wisconsin and earned her PhD in biochemistry at the University of Wisconsin–Madison. Her research and teaching interests include the human health impacts of climate change, chemical pollution, food insecurity, and environmental activism. She recently published an article about environmental contamination from fluorinated ski wax use in the journal Chemosphere, co-authored with Skylar Tupper. Website. Twitter. Contact.

Clare Sullivan is a Ph.D. candidate in the Geography Department at the University of Wisconsin–Madison. She studies the ecological impacts of land use change. Her current work focuses on cattle ranching, deforestation and environmental governance in Colombia. She has an M.I.A. from Columbia University and a B.A. from Washington University in St. Louis. She loves to cross-country ski. Twitter. Contact.

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