Rainwater almost everywhere on Earth has unsafe levels of ‘forever chemicals’, according to new research. Per- and poly-fluoroalkyl substances (PFAS) are a large family of human-made chemicals that don’t occur in nature. They are known as ‘forever chemicals’ because they don’t break down in the environment. They have non-stick or stain repellent properties so can be found in household items like food packaging, electronics, cosmetics and cookware. But now researchers at the University of Stockholm have found them in rainwater in most locations on the planet - including Antarctica. There is no safe space to escape them.
Rainwater everywhere is unsafe to drink
Safe guideline levels for some of these forever chemicals have dropped dramatically over the last two decades due to new insights into their toxicity. “There has been an astounding decline in guideline values for PFAS in drinking water in the last 20 years,” says Ian Cousins, lead author of the study and professor at the Department of Environmental Science, Stockholm University. For one well-known substance, the “cancer-causing perfluorooctanoic acid (PFOA)”, water guideline values have declined by 37.5 million times in the US. “Based on the latest US guidelines for PFOA in drinking water, rainwater everywhere would be judged unsafe to drink,” he says. "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.” What risk do ‘forever chemicals’ pose to our health? The health risks of being exposed to these substances have been researched widely. Scientists say that they could be linked to fertility problems, increased risk of cancer and developmental delays in children. But others say that no cause and effect can be proven between these chemicals and poor health. Despite this, and as a result of this new research, some are calling for tighter restrictions on PFAS. “It cannot be that some few benefit economically while polluting the drinking water for millions of others, and causing serious health problems,” says Dr Jane Muncke, managing director of the Food Packing Foundation in Zurich who wasn’t involved in the study. “The vast amounts that it will cost to reduce PFAS in drinking water to levels that are safe, based on current scientific understanding, need to be paid by the industry producing and using these toxic chemicals.” The time to act, she says, is now.
Children and adults in Ghana are at risk
Children and adults are at risk of dangerous health effects from drinking roof runoffs. That is the conclusion of a research by the scientists at the Department of Chemistry, Kwame Nkrumah University of Science and Technology. With no potable water running through taps in many homes in Ghana, rainwater harvesting is an alternative source of water. However, the roofing materials have been identified to affect the water quality. The research published in the 2022 edition of the journal, Science of the Total Environment, sought to find certain substances and how they can impact consumers’ health. “We wanted to assess heavy metals concentration, physicochemical and bacteriological parameters in roof runoffs and estimate the water quality index and health risk these metals pose to consumers,” lead scientist, Prof. Osei Akoto said. For the study, rainwater was harvested from Aluzinc, Aluminum, Galvanized, and Asbestos roofing materials within the Ejisu municipality. The scientists used rainwater collected directly from the sky as comparison. They found heavy metals such as Cadmium, iron, chromium and some germs were above the WHO standard. Cadmium in runoffs from asbestos roofing, for instance, was found to pose the biggest risk. “All runoffs from the four roofing materials recorded Cd, Fe, Cr, turbidity, pH, E.coli, total and fecal coliform levels above WHO limit for drinking water. “Cadmium recorded the highest non-cancer health risk to children and adults in all the roof runoffs,” he explained. “The estimated water quality index for runoffs from the four roofing materials exceeded 100 indicating their unsuitability for drinking. “Hazard quotients of 9.53 and 4.08 were estimated for a child and an adult respectively via oral exposure to Cd in runoffs from Asbestos roofing material,” he said. The water collected directly from the sky was however much safer. “There was a significant variation in pH, EC, Zn, Cd, Cr, Fe, E. coli, total and fecal coliform levels between control samples and roof runoffs,” he noted. The researchers are therefore advising against drinking rainwater.