Perfluoroalkyl And Polyfluoroalkyl Substances (PFASs): What You Need To Know
Stephanie Angione, Ph.D. | Scientific Contributor
What are Perfluoroalkyl And Polyfluoroalkyl Substances (PFASs)?
Fluorinated substances include a diverse range of chemical compounds that all contain at least one fluorine (F) atom. These substances vary in the amount of fluorine atoms they contain, and those that are highly fluorinated, or contain many F atoms per carbon (C) atom are referred to as perfluoroalkyl substances. These highly fluorinated substances are unique in their hydrophobic (water repellent) and lipophobic/oleophobic (fat/oil repellent) properties, as well as their general chemical and thermal stability.
These properties have made PFASs common in many types of applications, including creation of non-stick cooking surfaces, stain and water resistant coatings on fabrics, creation of oil/fat resistant food packaging and also in foam materials used to fight and prevent fires. Additionally, the automotive, aerospace, and construction industries have widely used these fluorinated substances for various applications due to their low friction properties.
Common PFASs include perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), which have been used in the production of Teflon and Scotchgard respectively. The manufacturer 3M phased out the production of PFOS in 2002 and the EPA helped manufacturers of PFOA phase out production completely in 2015.
How Do PFASs Contaminate The Environment?
PFASs are deemed “emerging contaminates” by the EPA; meaning that they are chemicals or materials thought to pose a potential threat to health and the environment, but haven't yet been regulated. PFASs contribute to environmental contamination largely due to the fact that they are highly resistant to degradation processes, and thus persist for many years in water, air and can enter the food chain via bioaccumulation in certain animal species.
The primary sources of human exposure to PFASs include:
- Consumption of contaminated drinking water
- Consumption of food that is packaged in materials containing PFASs, which have included fast food containers, microwave popcorn bags. (Most food manufactures have stopped using PFASs in these types of packaging).
- Consumption of food that contains PFASs, including fish and shellfish
- Contact (hand to mouth) with clothing, carpets or other fabrics that have been treated with PFASs. (Skin exposure to PFASs on their own does not cause significant absorption into the body).
- Industrial exposure to workers who manufacture of utilize PFASs containing products
Since PFOS and PFOA are two of the most common PFASs, exposure to these compounds is widespread. These PFASs, as well as the many others, accumulate in the human body and are only broken down very slowly. These compounds take anywhere from 2-9 years to be eliminated. Thus, most people in the US have detectable amounts of PFASs in their blood. However, due to the global stewardship program established by the EPA to phase out all production of PFASs by 2015, the overall blood concentration in the US population is declining.
What Are The Health Effects Of PFASs?
Although there is no consistent medical evidence of the health effects of PFASs in animals and humans, a number of adverse effects have been demonstrated in both animal and epidemiological human studies. The main effects of PFASs on health in animal studies of rodents exposed to PFOS and PFOA include changes in liver function, hormone levels and adverse effects to developing fetuses. The reported effects on fetal development include low birth weight and length, delayed growth and neonatal mortality.
The discovery of persistent contamination of drinking water sources with PFOA in West Virginia and Ohio prompted a large epidemiological study called the C8 Health Project. The study included nearly 70,000 individuals who had elevated PFOA levels in blood- approximately 500% higher than the representative population. The study found statistical correlation between elevated blood concentrations of PFOA with ulcerative colitis, impaired thyroid function, high blood cholesterol, testicular cancer, kidney cancer and preeclampsia.
How do PFASs Contaminate Drinking Water?
In 2016 the EPA released a lifetime health advisory for PFOA and PFOS in drinking water. This advisory indicates that the individual or combined concentration of PFOA and PFOS in water should be less than 70 parts per trillion (ppt). This EPA guideline is not an enforced limit- it simply provides guidance to local public health officials. However, under EPA guidelines issued in 2012, water systems are required to monitor. levels of PFOA and PFOS. The results of this monitoring effort can be found on the National Contaminant Occurrence Database. Together with data collected under the monitoring effort and established assessments of human health effects, the EPA will make a regulatory determination to include PFOA and PFOS in national drinking water regulations.
Communities that have sources of drinking water contaminated with PFASs are typically localized and associated with a specific industrial facility or area used for firefighting. Both PFOA and PFOS have been found in drinking water systems due to this kind of localized contamination. A 2016 study of drinking water in the US found unsafe levels of PFASs at the EPA minimum level of 70 ppt in 194 out of 4,864 water sources in 33 states. Of these states, 75% of the contaminated water sources were found in order of frequency: CA, NJ, NC, AL, FL, PA, OH, NY, GA, MN, AZ, MA, and IL. Water sources with the highest levels of PFAS contamination were near industrial sites and military bases, and one of the major contributing sources was found to be firefighting foam.
How Do I Find Out If My Drinking Water Is Contaminated With PFASs?
If you are concerned about PFOA, PFOS or other PFASs contaminants in your drinking water and are served by a public water system, your local water supplier is required to issue a Consumer Confidence Report that lists contaminant levels in the water supply. If you have a private well, a laboratory can test your drinking water.
If you get water from a household well, the local health department should have information about ground water quality and contaminants of concern, but it is often a good idea to have your water tested by a certified laboratory for PFAS contaminants. The EPA’s Safe Drinking Water Hotline (800-426-4791) can provide additional resources in your local area.
How Can I Remove PFASs From My Drinking Water?
Some public water systems employ methods (like granulated or powdered activated carbon) to reduce PFOA and PFOS at the municipal level. Higher end home water filters that use highly porous activated carbon as part of the active filtration media blend or reverse osmosis can remove these common PFASs from drinking water.
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