The writer is a science commentatorThe 2019 film Dark Waters, starring Mark Ruffalo, helped to thrust “forever chemicals” into the public consciousness. It dramatised a legal case brought against DuPont for contaminating water supplies in West Virginia, alleged to have contributed to cattle deaths and cancer clusters among locals. The case ended in 2017 with a $671mn settlement for about 3,500 plaintiffs.

Concern over the chemicals — more properly known as perfluoroalkyl and polyfluoroalkyl substances, or PFAS — has snowballed of late. Thousands of US lawsuits targeting major chemical companies have been filed and agencies globally are tightening regulation. The lawsuits have drawn comparisons with past “toxic torts” regarding substances such as asbestos and tobacco, rattling investors and insurers. 

The legal dimension is also spurring scientific sleuthing to work out exactly who is responsible for the chemicals, which have been found in the environment, in wildlife and in humans. “We know PFAS are everywhere,” says Patrick Byrne, a researcher in hydrology and environmental pollution at Liverpool John Moores University in England, who published research last month showing the River Mersey had one of the worst levels recorded globally for a river basin. “To do something about the problem we need to figure out how, where and when PFAS are entering the environment so we can trace them back to their source.” Rapidly evolving scientific methods, such as chemical fingerprinting, might make the difference in the widening war against these eternal pollutants.