PFAS and wildlife: How can we assess exposure risk?
October 22, 2020
October 22, 2020
How are scientists determining if the presence and concentration of PFAS in the environment could be harmful to animals?
The more we learn about PFAS, the more our concern for their impact on the environment grows.
PFAS is the acronym for a broad group of manmade chemicals. We find these perfluoroalkyl and polyfluoroalkyl substances in packaged foods and in industrial and commercial products such as polishes, waxes, cleaners, and paints. You’ll also find PFAS in firefighting foam, also known as aqueous film forming foam.
There are more than 5,000 substances in the PFAS family. They are ubiquitous, highly persistent, and some are toxic. Environmental agencies and departments in the US, Canada, and Australia recognized that some of these substances could be harmful to human health. Over the last two decades, some jurisdictions have developed drinking water standards and health-based guidance values.
But what are the impacts of PFAS on wildlife? Where are we in our understanding of how this family of chemicals impacts the organisms in our ecosystems? And what do we still need to accomplish?
From initial studies, it was evident that there could also be non-human impacts associated with PFAS compounds. But it was not until recently that studies addressed the potential for exposure and effects to natural habitats and the organisms they support. It is very likely that PFAS compounds move via overland water, like ditches and streams, and migrate into groundwater. Ultimately, PFAS ends up in aquatic ecosystems. Early studies focused on the potential effects to animals that use these habitats, such as fish-eating birds and mammals. Questions about PFAS compounds resulted in many laboratory and field studies. The goal was to determine which compounds posed the greatest concern and what concentrations could result in lethal effects.
In this blog, I’ll explore the history and status of US and international efforts for evaluating impacts to wildlife from PFAS exposure. I’ll also look at an exciting new tool for predicting exposure and subsequent risk to wildlife associated with aquatic habitats.
There is hope that PFAS exposure in wildlife will be significantly reduced in the future.
In February 2019, the Interstate Technology and Regulatory Council (ITRC) provided a fact sheet of various international and US (federal and state) PFAS screening or health advisory values. These focused primarily on groundwater and drinking water. Few values addressed surface water. As such, they did not address aquatic ecosystems.
In the US, the Strategic Environmental Research and Development Program (SERDP) leads the effort to develop ecological risk assessment tools for evaluating potential risks of PFAS to wildlife. It is part of the U.S. Department of Defense’s Environmental Science and Technology Program (in partnership with the Department of Energy and the Environmental Protection Agency).
In May 2017, these organizations conducted a PFAS workshop. The goal was to provide guidance for future research, management, and remediation of PFAS contaminated sites. A summary report of the workshop was released in November 2017.
In 2018, the Australian Department of Defense conducted an ecological risk assessment at a military base that had been contaminated with PFAS. Their study addressed potential impacts to both aquatic and terrestrial receptors. In the Australian study, contamination levels at which negative impacts are likely in various animals were only available for two classes of PFAS compounds—PFOS (Perfluorooctanesulfonic acid, believed to be the most problematic) and PFOA (Perfluorooctanoic acid). Remember, there are more than 5,000 chemicals in the PFAS family.
The May 2019 Society of Environmental Toxicology and Chemistry’s (SETAC) Integrated Environmental Assessment and Management journal published a series of papers that addressed PFAS in the environment. These papers looked at the concentrations and fate of PFAS in environmental media, such as soil, water, and sediment. They also looked at PFAS in animals and the mechanisms that transfer PFAS from one generation to the next.
After the journal’s release, in November 2019, SETAC North America held a focused topic meeting titled: “Environmental Risk Assessment of PFAS.” The meeting addressed PFAS contamination, including environmental sources, chemistry, fate and transport, exposure, ecological toxicity, and risk assessment and characterization.
Most recently, at a public meeting in early March 2020, SERDP released a helpful beta version of a customizable Microsoft Excel modeling tool. This tool is designed to help ecological risk assessors understand the likely effects of various concentrations of PFAS in aquatic food webs.
This model can help scientists predict risk levels for resident birds and mammals. The tool is for common species, as well as threatened and endangered species. Since the Model Tool can be customized for each project, it lets users enter data specific to the site under investigation, such as the concentrations of PFAS in sediment, water, plants, and animals. Users can also enter exposure factors for relevant wildlife species, such as body weight, food ingestion rate, home range, and more.
Finally, the model calculates a hazard quotient (HQ) for each species and each individual PFAS compound. An HQ is used to gauge how critical the risk is to the species from the PFAS compound under consideration.
So, what’s on the horizon to further help scientists determine if the presence and concentration of PFAS could be harmful to animals? First, researchers at various institutes and organizations continue to learn and experiment on the likelihood for PFAS compounds to travel and remain in the environment. Other scientists are working to discover the various physiological threats that PFAS pose to wildlife. SERDP is working to collate data and develop a new spreadsheet that can be used by risk assessors to predict potential risks to wildlife in terrestrial settings.
With many countries phasing out the production of some PFAS compounds or reducing the number of compounds commercially available, and with industries working to curtail the spread of these harmful compounds, there is hope that PFAS exposure in wildlife will be reduced in the future. But, currently, it’s paramount that industry be diligent. To this end, affected industries must keep up to date on the science of PFAS through regular consultation with knowledgeable experts.
Learn more about PFAS and what our experts are doing to help address them.