Britannica Sources used in this answer

Why do PFAS chemicals persist in water and soil?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A labeled diagram of the periodic table entry for fluorine, showing its atomic number 9, symbol F, atomic weight 18.998, electron configuration, and indicating it is a halogen and a gas at room temperature. — fluorine Properties of fluorine.

Per- and polyfluoroalkyl substances (PFAS) persist in the environment primarily due to their unique chemical constitution, which features fluorine atoms attached to chains of carbon atoms. This specific molecular structure makes these synthetic compounds highly resistant to degradation, earning them the nickname "forever chemicals".123

Because they are designed to repel oil and water and withstand high temperatures, they do not break down easily through natural processes. This durability allows them to accumulate extensively in soil and water, where they remain for long periods. Their persistence is a significant environmental and public health concern, as they are difficult to remove using conventional water treatment methods, leading to widespread contamination of drinking water and food sources.231