Phasing out is not enough — the problem with fluorinated chemicals in wildlife
During a time of cultural and political polarization, a class of chemicals called per- and polyfluoroalkyl substances, or PFAS, may be one of the few commonalities shared by all Americans. These human-created industrial chemicals are found in the blood of 99 percent of U.S. adults, as well as babies in the womb and children.
But PFAS pollution isn’t limited to humans. A recent study by our group looked for 36 new and already banned types of PFAS in juvenile seabirds from three U.S. East Coast habitats near and far from human sources of these chemicals. We found high levels of a particular type of well-known PFAS, called PFOS, in every bird. PFOS was also found at high levels when U.S. East Coast seabirds were last surveyed for PFAS around 2001. However, PFOS was phased out of production in the U.S. in 2002, and listed for international regulation by the Stockholm Convention in 2009.
But here’s the rub: finding this decommissioned chemical in these birds was not a surprise to us. Even today PFOS remains the most commonly found PFAS in wildlife from remote places like the Arctic as well as in wildlife living adjacent to human populations.
But how does a compound banned two decades ago remain so abundant in wildlife around the globe today? Answer: uncanny persistence. PFOS and other types of well-known PFAS, or legacy PFAS, are tremendously stable in the environment; there are no known environmental pathways to break them down, earning them the nickname “forever chemicals.”
Those PFAS that can break down, generally termed “precursors,” often transform into more stable types of PFAS, rather than disintegrating into harmless fragments. We use precursors in a variety of consumer goods and industrial processes, such as coatings of our food packaging material or outdoor textiles, or replacements for phased-out PFAS in fire-fighting foams (and this is entirely legal). Over time, these precursors leach out of their intended uses and transform in the environment or within living organisms to toxic, stable PFAS like PFOS. This serves as an ongoing pathway sustaining PFOS and other legacy PFAS in the environment, as we continue to churn out products and processes that incorporate such precursor compounds.
Beyond precursors, we also continue to create new, stable PFAS to replace phased-out, legacy PFAS. These new structures, often referred to as novel PFAS, are poorly studied, yet many appear to cause negative impacts in living creatures akin to the compounds they replaced. In our study, we found high levels of several novel PFAS in birds hatched downstream from a PFAS production site in North Carolina, as well as in seabirds with no known connection to that production area. The latter suggests these novel PFAS are highly persistent and capable of traveling long distances in the environment, identical to their predecessors.
This complex exposure scenario boils down to a lose-lose situation for wildlife like the seabirds in our study, as they continue to be exposed to new and familiar PFAS via multiple pathways. There is no mitigation in sight for wildlife or the ambient environment, as we cannot put the nightmarish genie back in the bottle, so to speak. For highly persistent chemicals like PFAS, once they have been released, their recovery is either impossible (in wildlife or in remote places) or very costly (in drinking water around the U.S.).
The ubiquity and persistence of these compounds is further heightened by their ability to cause negative impacts in living creatures at very low concentrations. Data from human studies tell us PFAS can cause negative health outcomes like impaired immune responses in kids or altered thyroid function at parts per trillion levels. One part per trillion equates to about one grain of sand in an Olympic sized swimming pool.
In wildlife, we possess a shockingly incomplete understanding regarding how new and familiar PFAS are impacting wild populations, as the effects of PFAS within fish and wildlife are poorly studied. The limited existing data suggests environmentally relevant concentrations of PFAS may negatively impact growth, development, reproduction, immunity or survival within marine mammals, seabirds and other birds.
We know that the long-term effects of other bioaccumulative contaminants (such as polychlorinated biphenyls, already phased out 50 years ago) continue to have population-scale consequences for biodiversity. Recent studies suggest that these polychlorinated biphenyls will cause the extinction of up to 50 percent of global killer whale populations over the next 100 years. The same level of investigation hasn’t yet been carried out for PFAS, but we note that PFAS are found at extremely high concentrations in many top predators, including seals and polar bears. PFAS have also been shown to impact marine mammal reproduction and immunity, similar to polychlorinated biphenyls. At a time when wild animals are thoroughly stressed through habitat loss, climate change and other large-scale stressors, they can ill afford other chronic persistent stressors like PFAS that reduce their resiliency and can adversely impact their health.
Our poor understanding of PFAS in wildlife and ecosystems translates to uncertainty regarding our own exposure to PFAS. Ecological health directly correlates to public health, as we rely on the same air, water and land systems that sustain wildlife. We also directly rely on wildlife for food; the European Food Safety Authority estimates up to 86 percent of dietary PFAS consumed by adults comes from fish and other seafood.
We find some level of PFAS essentially everywhere we look in air, water, sediment, soils, ice and living creatures. Simply banning (or, in the case of the U.S., phasing out) highly persistent chemicals is needed but still too late. Instead, PFAS serve as a timely and unfortunate reminder that truly protective actions by EPA and other regulatory bodies must consider whether any production of such highly persistent chemicals is justified.
Rainer Lohmann is a professor of Oceanography at the University of Rhode Island’s Graduate School of Oceanography and the director of the STEEP Superfund Research Program.
Anna Robuck is the lead researcher in the study “Legacy and Novel Per- and Polyfluoroalkyl Substances (PFAS) in Juvenile Seabirds from the U.S. Atlantic Coast,” and she is currently finishing a PhD in Oceanography at the University of Rhode Island Graduate School of Oceanography. She has researched PFAS in water and wildlife for the last four years as part of the STEEP Superfund Research Program. Follow her on Twitter @annaruthski.