Many commercial and industrial products depend on synthetic compounds for their unique chemical properties. One widely used class of waterproof and fat-repellent compounds, known as per-and polyfluoroalkyl substances (PFAS), can be found in everything from non-stick coatings for cookware to fire-extinguishing foam. While they were first developed in the 1930s, the National Institute of Environmental Health Sciences estimates that over 4,700 PFAS exist today.
However, despite their popularity, public concern surrounding PFAS contamination has grown in recent years, due to human health studies linking drinking water contamination to autoimmune disorders and other conditions. Although chemical manufacturers have been aware of the dangerous side effects associated with PFAS exposure for over 40 years, they are still widely used and continue to contaminate communities and the environment. Although most research has been geared towards health impacts on humans, similar effects have been observed with animals.
PFAS have contaminated groundwater, rivers, and oceans worldwide through runoff and air emissions. High exposure areas include locations near chemical manufacturing and processing plants, military bases, and wastewater treatment sites. However, the compounds are also present in remote areas within the environment and within organisms, including ringed and grey seals in the Arctic. Most regions are contaminated in lower concentrations from long-range transport through oceans and the atmosphere.
One of the “miracle” properties of PFAS is their highly stable chemical bonds that leave them resistant to breaking down. While this makes them industrially useful, it also allows them to persist and accumulate in the environment and within organisms. As a result, the most severe health impacts tend to occur in organisms at the top of the food chain. Recent research has provided insight on how PFAS may impact marine ecosystems:
PFAS in North Shore birds – Shearwaters in Massachusetts Bay, who live offshore and rarely travel inland, were found dead with high concentrations of PFAS compounds in their livers. The same compounds were found in seabirds in Cape Fear, indicating that PFAS travel long distances. PFAS are expected to negatively impact reproductive health in seabirds.
Immunotoxicity in mussels – Four different PFAS compounds were tested within green mussels, and higher concentrations were associated with up to 50% decreased immune function. The researchers note that an upper threshold may exist that results in complete immune shutdown within marine organisms.
Liver damage and immune response in fish – At a site near a wastewater treatment plant that discharges into the Atlantic Ocean, researchers noted decreased enzymatic function in the liver, cellular damage, and decreased immune function in bass. Bioaccumulation in marine and estuarine fish is of significant concern for humans and piscivorous predators since PFAS concentrations magnify through trophic levels.
Chronic immune activation in dolphins– Multiple studies on bottlenose dolphins show that chronic exposure to PFAS leads to elevated autoimmune responses and tissue toxicity. One case study in South Carolina also identified potential impacts on kidney and liver function.
Threats to aquatic invertebrates and algae– Elevated levels of PFAS decrease algal biomass and lead to chronic toxicity, with implications for all organisms in upper trophic levels. Oxidative damage is also found to occur within algae.
Bioaccumulation within Arctic predators– Bioaccumulation was assessed in this study by measuring the concentration of 22 PFAS compounds in the liver and blubber of seals and the fat and liver of polar bears. Elevated concentrations of PFAS were found within polar bears compared to seals. Contamination within marine ecosystems of the Arctic is of great concern, emphasizing the potential for persistence and long-distance transport.
A new exposure pathway through climate change– Ice cores in Norway show elevated levels of numerous PFAS compounds, which may lead to increased concentrations in marine ecosystems as the Arctic climate continues to warm and trigger glacial melting.
No location on Earth is known to be PFAS-free, and estimates of the scope and magnitude of contamination are likely underestimated. Scientists at Harvard recently developed new techniques to detect PFAS and found that six watersheds in Cape Cod exceed the Maximum Contaminant Levels (MCLs) set by Massachusetts Department of Environmental Protection in September 2020. Beyond the impact on drinking water supplies for Cape Cod residents, effects on local freshwater and marine ecosystems are unknown.
Check out part two of this post to learn more about the PFAS Task Force: a coalition that will investigate PFAS contamination within Massachusetts throughout 2021.