(WGNO) — Rainwater everywhere is unsafe to drink, according to new a new study published in the journal Environmental Science & Technology.

Researchers at Stockholm University and ETH Zurich say the amount of “forever chemicals” found in rainwater is well above standards set by the U.S. Environmental Protection Agency.

“Forever chemicals” are a nickname for per- and polyfluorinated alkyl substances (PFAS) that are extremely persistent in the environment and hard to break down.

PFAS are man-made chemicals and considered hazardous to human health. According to the study, PFAS have been associated with a wide range of medical issues, including cancer, learning and behavioral problems in children, infertility and pregnancy complications, increased cholesterol, and immune system problems.

The substances are spread across the globe through the atmosphere and can be found in rainwater and snow — even in the most remote locations on Earth.

During the last 20 years, guideline values for PFAS in drinking water, surface waters and soils have decreased dramatically due to new insights into their toxicity.

“Based on the latest U.S. guidelines for PFOA in drinking water, rainwater everywhere would be judged unsafe to drink. 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,” said Ian Cousins, the lead author of the study and professor at the Department of Environmental Science at Stockholm University.

The Stockholm University team have worked for more than ten years conducting laboratory and field work on the atmospheric presence and transport of PFAS.

Researchers note the levels of some harmful PFAS in the atmosphere are not declining even after being phased out by major manufacturers two decades ago.