Scientists at the University of Stockholm have released findings from a decade-long investigation into the impact of per- and polyfluoroalkyl substances (PFAS).
They found that, when analyzed against US contamination guidelines, rainwater is unsafe for human consumption all over the world. This is due to PFAS levels.
Deemed “forever chemicals,” PFAS build up in human and non-human animals and the environment, contributing to a litany of serious consequences. These include an increased risk of cancer, fertility problems, and developmental issues in children.
Research has also linked reduced vaccine effectiveness to PFAS exposure.
What are PFAS?
There are thousands of PFAS in existence. All human-created, they are chemicals used in food packaging, home furnishings, electronics, cosmetics, and animal agriculture. Most people are likely to come into contact with them on a daily basis.
In the case of animal agriculture, the contamination cycle is easy to identify.
PFAS are found in biosolids, a by-product of sewage wastewater treatment. These are commonly used as free fertilizer and spread across farmland, allowing PFAS to seep into groundwater. They are also absorbed by crops and often fed back to livestock, bringing them into the food system.
As they are produced and used, PFAS are released into the environment, either directly into the air or via waterways. From here, they dissipate throughout the atmosphere and later come back to the ground as global rainfall, thus creating a cycle of natural pollution.
Now that the chemicals have been found in Antarctica and Arctic sea ice, their impacts are being more deeply scrutinized.
Could eating more plant-based foods reduce PFAS exposure?
The long-term effects of PFAS are still being investigated. However, reducing our interactions with them is deemed a prudent move, particularly for children.
There are more than 4,500 chemicals in the PFAS family, making them hard to avoid altogether. But there are meaningful steps that can be taken. These include not using non-stick cookware and choosing home cooking over convenience food.
Recent research also suggests that human blood levels of PFAS may be reduced by following a plant-based diet.
Fish, in particular, ingest high levels of PFAS as they enter fresh and salt water reserves through various means. Key facilitators include manufacturing run-off, rubbish pollution, and contaminated rainwater collection.
As a result, fish consumption advisories are increasingly being issued.
Further, livestock are routinely given feed that contains PFAS, which builds up in their bodies over time. These are transferred to humans when the animal is slaughtered and eaten.
How many PFAS are there in rainwater?
In June, the Environmental Protection Agency (EPA) adapted its guidelines that control how much perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) can be present in drinking water.
Considered two of the most prolific PFAS, both have been significantly reduced, from 70 parts per trillion down to 0.004 and 0.02 parts per trillion respectively.
The University of Stockholm researchers used the EPA guidelines as a benchmark when assessing the levels of PFAS in rainwater collected from around the world. Both PFOA and PFOS “often greatly exceeded” the accepted limits, they found.
“Based on the latest US guidelines for PFOA in drinking water, rainwater everywhere would be judged unsafe to drink,” Ian Cousins, lead author of the study and professor at the University of Stockholm Department of Environmental Science, said in a statement.
He continued: “Although in the industrial world we don’t often drink rainwater [directly], many people around the world expect it to be safe to drink, and it supplies many of our drinking water sources.”