Polar Bears to Public Water Supplies: Growing Concerns over an Emerging Group of Contaminants

A lot of news has been made recently about perflourinated chemical contaminated public drinking water. Perflourinated chemicals, or PFCs, are a family of chemicals that have been manufactured since the 1940s in the United States. Of the family of PFCs, perflourooctanoic acid (PFOA) and perflourooctanesulfonic acid (PFOS), are of particular interest. These compounds are both manufactured and can form from the breakdown of other PFCs and are extremely persistent in the environment. The toxicology of these substances is not well understood, but they have both been linked to deleterious health effects in humans.   

PFOA has been used to make other products more resistant to water and grease and can be found in many consumer goods. Chemical mixtures containing PFOS behave as surfactants, reducing the surface tension of water. Firefighting foam containing PFOS has found a particularly useful application on airbases across the country. The foam exhibits a fantastic ability to expand, penetrate, and smother jet fuel fires. Until 2002, when production of PFOS foam was ceased by 3M following growing environmental concerns, considerable quantities were used across the globe. 

PFCs are generally water soluble. Their chemical characteristics make them mobile in surface water and groundwater aquifers. They aren’t readily biodegraded, volatilized, or bound to organic material in the subsurface like many petroleum hydrocarbons. In short, they just kind of stick around. EPA has commented that in water, concentrations only dissipate by spreading out or diluting. According to one study referenced by EPA in the May 2016 Drinking Water Advisory Study for PFOS:

“Because of its persistence, it can be transported long distances in air or water as evidenced by detections of PFOS in the Arctic media and biota, including polar bears, ocean going birds, and fish found in remote areas (Lindstrom et al. 2011a; Smithwick et al. 2006).”

Every five years, public drinking water suppliers conduct sampling in accordance with the EPA Unregulated Contaminant Monitoring Rule (UCMR). This program identifies up to 30 unregulated, emerging contaminants and requires public water suppliers to conduct routine monitoring for these substances for a period of three years. During the third UCMR monitoring cycle, which ran from 2013 through 2015, five PFCs, including PFOS and PFOA, were included in the sampling list. 

During the UCMR monitoring program, concentrations detected in drinking water were compared to the lowest levels that can be measured by a laboratory, the minimum reporting level, and the EPA health advisory level, which is based on peer-reviewed studies and animal testing. If UCMR monitoring determines that substances are widespread and present at concentrations above the health advisory levels, the contaminants may become regulated under the Safe Drinking Water Act.  

As of July 2016, during the last UCMR monitoring period, 2% of the 4,909 public water supplies have reported concentrations of PFOS and PFOA above 0.02 parts per billion (ppb) – the minimum reporting level.  Concentrations above the EPA health advisory level of 0.07 ppb were detected in half of these public water systems (46 of the 4,909). For comparison, the current health advisory level for PFOS and PFOA is more than seventy times lower than the maximum contaminant limit of benzene (5 ppb), a well known carcinogen and EPA regulated substance. Concentrations several orders of magnitude higher than the EPA health advisory level have been detected in groundwater and public water supplies located closer to military bases across the US where PFOS fire suppression foam has been used.  

Drinking water isn’t the only way to be exposed to PFCs. Most people will come in contact with them through their food or food’s packaging. PFCs can accumulate in the tissue of livestock, fish, or vegetables through contaminated soil, surface or groundwater, and the air. PFCs have also been used as waterproofing treatment for everything from clothing and carpet to ski wax and cookware. As recently as January 2016, FDA banned the use of grease-proof paper coatings with impurities that included PFOS. 

The reality is, concentrations of PFCs like PFOS and PFOA are likely already present in most of the general population. A study conducted between 1999 and 2012 showed concentrations of PFOS may be detected in up to 99% of the US population. The half-life of PFOA in the human body is over two years and up to eight and a half years for PFOS. 

To date, human and animal cancer studies involving PFOS and PFOA have been inconsistent and showed limited correlation. Results of other health studies have implied potential impaired immune function, fertility issues, diabetes, and high cholesterol but with equally nebulous correlation. Animal studies have shown incidences of cancer, although the exposure concentrations were higher than most humans will ever experience. The book is very much still out on the low level chronic exposure effects of PFCs as evidenced by the varying limits proposed by leading institutes and agencies. In 2015, the Harvard School of Public Health released an analysis suggesting a safe drinking water level of 0.001 ppb, below the EPA health advisory level of 0.07 ppb. 

Growing public awareness has contributed to many companies phasing out the use of these chemicals in consumer goods. Stockpiles of PFOS firefighting foam have dwindled since production was halted by the primary manufacturer. Even though the pipeline of new PFCs may be shutting down, we are finding that their distribution in the environment is already widespread. Polar bears in the arctic and public drinking water utilities alike will be closely watching this situation as it develops.