The Ongoing Study From the NASEM Intended to Provide Guidance for Clinicians on the Health Impacts of PFAS

A growing number of US veterans have developed serious health ailments after facing prolonged exposure to toxic chemicals they could not avoid during their military duties. This pervasive, unsafe exposure to toxic agents resulted in adverse health effects such as neuroendocrine and immune dysregulation, autonomic nervous system irregularities, and multiple types of cancer.

Further research into the mechanisms that underlie such health effects in exposed veterans is paramount to developing biomarkers of exposure and effect and preventing similar problems for military personnel in future deployments, and also for developing new treatments.

On February 4, 2021, the expert committee appointed by the National Academies of Sciences, Engineering, and Medicine (NASEM) has held its first meeting to consider current evidence regarding human health effects of per- and polyfluoroalkyl substances (PFAS)—a group of synthetic organofluorine chemical compounds.

In 2022, the NASEM is expected to provide the Centers for Disease Control and Prevention (CDC), the Agency for Toxic Substances and Disease Registry (ATSDR), and the National Institutes of Environmental Health Sciences (NIEHS) “an objective and authoritative review of current evidence regarding human health effects of those PFAS being monitored in the CDC’s National Report on Human Exposure to Environmental Chemicals,” and also recommendations regarding potential changes to CDC and ATSDR PFAS clinical guidance, including:

• criteria and considerations to guide evidence-informed decisions for testing PFAS levels in blood and urine samples;
• concentrations of PFAS in serum and urine that could inform clinical care of exposed patients; and
• adequate follow-up and care specific to PFAS-related health endpoints for those patients known or suspected to be exposed to PFAS.

Currently, ATSDR, the United States nonprofit, non-governmental organization involved with hazardous waste issues, provides detailed PFAS information for health care providers, in its report entitled “An Overview of the Science and Guidance for Clinicians on Per- and Polyfluoroalkyl Substances (PFAS)”. It must be also mentioned that the ATSDR and the NIEHS fund the ongoing study from the National Academies which will provide advice for clinicians about PFAS testing and how test results should inform clinical care.

The Adverse Health Impacts Associated With PFAS Exposure: A Widespread Concern

Many military bases were used for routine firefighting training exercises for a long time. Results of groundwater sampling around many of these sites indicated the presence of PFAS compounds used in fire suppression foams. Many communities where PFASs have been found in drinking water are near these installations. The US Navy and Air Force have put programs in place to identify and address PFAS exposures in affected communities.

Although the potential health effects of PFAS in humans are not yet well-understood by scientists, multiple studies have found that exposure can result in unwanted health effects when the chemical compound has reached a high enough concentration at a certain site in the body. The CDC has issued warnings that high levels of per- or poly-fluorinated substances may impact the function of the liver, thyroid, pancreas, and hormone levels and increases the rate of certain types of cancer.

In 2020, the CDC’s Agency for Toxic Substances and Disease Registry released a report saying conclusive evidence indicates that exposure to elevated PFAS levels can have a negative effect on the immune system and increase the risk of developing severe COVID-19. Studies have also shown that exposure to fluorinated compounds may interfere with the effectiveness of childhood vaccines and adult flu vaccines.

While toxicity and carcinogenicity studies have raised important concerns, there are still critical gaps in the science surrounding PFAS and human health. Out of the more than 4700 known PFAS compounds, only a small fraction of these have been extensively studied for their risks. We still don't know the precise molecular ways that they produce toxicity, how much PFAS exposure is safe for humans, or whether there are important differences in toxicity between different PFAS compounds. Closing these gaps is paramount to set regulatory limits for PFAS exposure and provide advice for people living in areas where PFAS substances have been detected.

In order to provide Americans with a margin of protection from a lifetime of exposure to PFOA and PFOS from drinking water, the US Environment Protection Agency (EPA) has set lifetime health advisory levels. In many military installations, the drinkable water was found to contain levels greater than the EPA’s safety baseline of 70 ppt. The Department of Defense identified 678 sites on active and former military bases where the toxic fluorinated chemicals were released or a suspected discharge occurred.

Health experts say PFAS chemicals are harmful at much lower levels than the EPA health advisory level. New studies say that PFASs affect the immune system at much lower levels than previously thought, particularly for children and other vulnerable people. Given the strength of the carbon-fluorine bond, PFAS are chemically and biologically stable and highly resistant to environmental degradation. Toxicology studies show that PFAS substances are easily absorbed after oral exposure and accumulate in the human body for long periods of time.

On May 25, 2021, the expert committee appointed by the National Academies will host the next committee meeting on Guidance on PFAS testing and health outcomes.

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