By Ramona Darlington
The Environment Working Group (EWG) recently released a report that claims up to 110 million Americans could have drinking water contaminated by PFAS (per- and polyfluoroalkyl substances) — much higher than the previous estimate of 16 million affected Americans.
So why the sudden increase? The 2016 study that determined the 6 million number looked at drinking water supplies where contamination exceeded various water quality standards from 10 to 90 parts per trillion (ppt) for several different PFAS. The EWG’s most recent report broadened the scope and found that when instead using a lower threshold of 2.5 ppt, the number of contaminated drinking water sources skyrocketed.
It is obvious that lowering the threshold would cause a jump in the number of affected people. The real problem, however, is that we do not actually know what the threshold should be. We do not know how much PFAS exposure is safe for humans. There is a chance that PFAS might only be harmful at the 10 ppt threshold the 2016 study used, but there is also a chance that PFAS could be harmful at the 2.5 ppt threshold. In order to accurately set standards and policies to best protect the American people from harmful chemicals in their drinking water, more research must be done.
PFAS have been tenuously linked to numerous health issues such as cancer, fetal development and fertility problems but there has been hardly any in-depth research done to determine their actual impact on human health, especially over time. We do not know exactly what levels — if any — of PFAS exposure is safe for humans, or what the differences in toxicity are between different types of PFAS.
And then there is the environmental impact to consider. PFAS take an unusually long time to break down because they are resistant to known contaminant degradation mechanisms, meaning contamination can last for a long time. PFAS can also end up a far distance away from the place where they were manufactured or used; in fact, PFAS compounds have been found as far away as Antarctica. Some PFAS compounds are soluble in water and therefore travel with the groundwater miles away from the point of release. However, we do not fully understand how PFAS compounds break down in the environment over time and how they travel to remote locations.
It is clear that PFAS are both extremely prevalent and potentially harmful to both humans and the environment. For a water contamination issue that has been compared to the 2015 lead contamination crisis in places like Flint, MI, the lack of knowledge and research on PFAS is startling.
The good news is that seems to be changing. Upon determining that PFAS may be harmful, the U.S. EPA launched the 2010/2015 Stewardship Program, which invited companies to commit to achieve a 95 percent reduction in facility emissions and work towards eliminating these chemicals from their products. This was the beginning of several steps taken to reduce the human and environment exposure to these compounds.
The EPA included analysis of six different PFAS compounds in their Third Unregulated Contaminant Monitoring Rule from 2013 to 2015 where they sampled public water systems serving more than 10,000 individuals. Previously, PFAS were not on the list of chemicals sampled for in the Unregulated Contaminant Monitoring Rule. This sampling effort provides EPA with an idea of how widespread the contaminant can be found in drinking water and therefore how many individuals are exposed to the chemical through their drinking water
In late 2017, the EPA launched a cross-agency effort to address PFAS. They have also already established non-regulatory drinking water life time health advisories for perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), which are two PFAS compounds that are commonly found in water contamination. In addition, several states including Michigan, Minnesota, Texas, New Jersey, and even Alaska have adopted their own regulatory values that are often lower than the EPA health advisory.
The EPA also recently released a solicitation for grant proposals through the National Center for Environmental Research to fund research into the fate and transport, risk and toxicity of these compounds.
Additionally, Congress’ most recent omnibus bill authorizes $63.8 million in funding for remediation and research efforts specifically related to PFOS and PFOA. This includes $43.8 for the Air Force Environmental Restoration fund, which allows the Department of Defense to identify, investigate, and remediate PFAS contamination on military sites; $10 million for the Centers for Disease Control and Prevention to study the health effects of PFAS, and an additional $10 million for health screenings related to contaminated water.
One of the most recent signs that the government is finally taking PFAS contamination more seriously? Just last month, the EPA held a National Leadership Summit on PFAS, bringing together stakeholders from across the country to discuss and identify actions to help address the challenge of PFAS contamination. The summit included representatives from over 40 states, tribes, and territories; 20 federal agencies; Congressional staff; associations; industry groups; and non-governmental organizations.
During the meeting, EPA Administration Scott Pruitt announced a four-part plan to tackle PFAS contamination:
While this plan — and all of Congress’s and the EPA’s previous actions — are important, they are still just baby steps towards fully tackling the PFAS problem. PFOA and PFOS are just two PFAS compounds out of hundreds — there are multiple other known PFAS compounds that we know hardly anything about. We do not know whether certain PFAS compounds are more toxic than others, or if certain compounds are linked to specific health issues that others are not.
We also still don’t know enough to make judgment on how much PFAS is too much for humans to come into contact with from a health and safety standpoint. Ongoing research that is taking place include research into the ecotoxicity of commonly detected PFAS compounds, fate and transport of these compounds in the environment, and methods to properly sample and analyze for these compounds in drinking water as well as soil samples.
Researchers are also looking into methods to remove these compounds from our drinking water and soil and not only remove them but also destroy them. A major research initiative is also to develop replacements for these PFAS compounds that do not affect human health and the environment. The results of these studies won’t be available for some time, but they represent an important step forward.
These gaps in our understanding make it difficult to set regulatory limits for PFAS exposure — currently the EPA has only issued lifetime health advisories for PFOA and PFOS, but not for any other PFAS compounds. It also makes it difficult to provide advice and remediation methods for people living in areas where PFAS have been detected. Whatever the threshold for safe human exposure to PFAS ends up being could mean the difference between 16 million affected Americans or 110 million.
It is clear that while these steps being taken by both Congress and the EPA are important, additional research is still needed to better understand the effects of PFAS contamination, address the very real human health and environmental concerns related to PFAS, and figure out how to reduce exposure risks and clean up PFAS-contaminated sites.
Ramona Darlington, PhD, is a Senior Research Scientist on the Battelle Environmental Services team. An experienced Remediation Engineer, Ramona works with government and commercial clients to evaluate environmental contamination and develop remediation plans for challenging contaminants, including PFAS.
Image credit: "Water Fountain 2," Josh, 2007, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/