Chemically, they consist of fluorine atoms attached to an alkyl chain, forming a fluorocarbon. This structure gives them a strong chemical inertness, or inability to react with other molecules. This is caused by the carbon-fluorine bond, which is very strong. It is due to this property that PFAS are used so extensively in the industrial sector.

However, this property has proved to be very problematic for not only the environment but also for public health. PFAS do not break down naturally in the environment. In fact, this has earned them a nickname: “the forever chemicals.”

Furthermore, when PFAS gets into your body, it stays there for many, many years. This is a major health concern, even if there isn’t a lot of conclusiveness among studies when it comes to finding a direct link between PFAS in the body and adverse health effects. So far, the strongest evidence for a connection is for dyslipidemia, a condition in which a patient has elevated cholesterol levels. This can lead to blood clots and heart disease.

Additionally, PFAS are water-soluble, so they can seep into water sources especially easily. Through water sources, PFAS can find their way into households via seafood, drinking water, etc.

Within the past decade, PFAS have garnered more and more attention, and so governments at the local and federal level have released recommended limits for these substances in drinking water in order to protect the public. The EPA has set its level for PFOA and PFOS (two of the most studied PFAS) at 70 parts per trillion (ppt). In my own state of Massachusetts, the limit of PFAS in drinking water was declared at 20 ppt for six PFAS, also known as the PFAS6: PFOS, PFOA, PFHxS, PFNA, PFHpA, and PFDA.

Sources:

mass.gov

nationalgeographic.com

wikipedia.org

Sunderland et al. (2019) A review of the pathways of human exposure to poly- and perfluoroalkyl substances (PFASs) and present understanding of health effects.