It’s unsafe to drink rainwater due to the ongoing presence of “forever chemicals,” according to a new study published in the journal Environmental Science & Technology.
PFAS are called “forever chemicals” because they can last for thousands of years. Various health conditions have been linked to PFAS contamination, including cancer, infertility, pregnancy complications, learning and behavior problems in children, immune system issues, and higher cholesterol, the researchers wrote.
Researchers found major environmental contamination of per- and polyfluoroalkyl substances, or PFAS, which are human-made chemicals used in numerous products, such as food packaging and waterproof clothing. The chemicals can spread in the atmosphere and are now found across the globe, including in rainwater, snow, soil, and even human blood.
During the last 20 years, countries have decreased their recommended limits for PFAS in drinking water, surface water, and soil due to new insights about their toxic nature, the researchers wrote. As a result, the levels in the environment are now higher than the recommended guidelines.
“Based on the latest U.S. guidelines for [perfluorooctanoic acid] in drinking water, rainwater everywhere would be judged unsafe to drink,” Ian Cousins, PhD, the lead study author and a professor of environmental science at Stockholm University, said in a statement. “Although in the industrial world we don’t often drink rainwater, many people around the world expect it to be safe to drink, and it supplies many of our drinking water sources,” he said.
Cousins and colleagues have done lab and fieldwork on the presence and spread of PFAS in the atmosphere for the past decade. In this study, they compared global guidelines with the levels of four types of perfluoroalkyl acids – perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) – in various sources, including rainwater, surface water, and soil.
They concluded that the levels of PFOA and PFOS in rainwater often “greatly exceed” U.S. guidelines for drinking water, as well as guidelines across Europe. The atmospheric spread has led to the soil being “ubiquitously contaminated” across the globe and the safe “planetary boundary for chemical pollution being exceeded,” they concluded.
In the U.S., for instance, the recommendations for PFOA levels have dropped from 70 parts per trillion to .004 parts per trillion, which is a factor of 37.5 million. At the same time, the researchers found that PFOA levels in drinking water exceed these guidelines in every part of the world, even in some of the most remote areas such as Antarctica and the Tibetan plateau.
U.S. manufacturers have largely phased out PFOA and PFOS during the last 2 decades, although some products still use them, according to USA Today. The main issue is that the chemicals already in the environment haven’t declined notably in recent years and will continue to persist, the researchers wrote.
The research team stressed the importance of quickly taking action to prevent further damage and contamination, which would require a “large investment in advanced cleanup technology” and “rapidly restricting uses of PFAS wherever possible.” But PFAS are now part of a natural cycling process, often spreading from seawater to marine air by sea spray aerosols, they wrote.
“The extreme persistence and continual global cycling of certain PFAS will lead to the continued exceedance of the above-mentioned guidelines,” Martin Scheringer, DSc, one of the study authors and a professor based in Switzerland and Masaryk University in the Czech Republic, said in the statement. “So now, due to the global spread of PFAS, environmental media everywhere will exceed environmental quality guidelines designed to protect human health, and we can do very little to reduce the PFAS contamination,” he said. “In other words, it makes sense to define a planetary boundary specifically for PFAS, and as we conclude in the paper, this boundary has now been exceeded.”
Parvathy Sukumaran 
