Are you concerned about contamination in your drinking water? I think everyone feels that their water should be clean and free of pollutants. One of the common pollutants is a class of compounds that simply do not break down. These are per- and polyfluoroalkyl substances, also known as PFAS compounds. Let's talk about PFAS compounds. Specifically, what they are, why are they trouble, and what is being done to address the contamination. Image of some PFAS contaminated sites from Northeastern University.