Rainwater globally is too contaminated for human consumption: Study

The fact that oceans, rivers and other bodies have been terribly polluted by human activities is old news. But new research suggests that rainwater around the world may also be polluted with “per- and polyfluoroalkyl substances” (PFAs), making it unsuitable for human consumption.

PFAs are dangerous chemicals that spread in the atmosphere globally. They are used to make fluoropolymer coatings that can resist heat, oil, stains, grease and water. Products using PFA include clothing, furniture, adhesives, food packaging, non-stick cooking surfaces, and electrical wire insulation.

As a result of their proliferation, they pollute even the most remote regions of the Earth. Over the past 20 years, new knowledge about the toxicity of these substances has meant that the maximum acceptable guide values ​​for PFAs in water have dropped dramatically. According to a paper published in Environmental sciences and technologies, this means that PFA levels in rainwater are above these guide levels worldwide. The study compared the levels of four PFAs, perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA), in various global environmental media including rainwater, soils and surface waters.

Although the research does not include studies that have sampled rainwater in India, Ian Cousins, the lead author of one study, told indianexpress.com that a similar conclusion can be drawn about rainwater in the country.

“As we see, rainwater levels around the world are similar. I think the study can be extrapolated to India. PFAs are used and disseminated globally, ”Cousins ​​said in an email interaction.

According to the United States Environmental Protection Agency, exposure to PFAs can cause a number of health risks including decreased fertility, developmental effects in children, interference with body hormones, increased levels of cholesterol and increased risk of certain cancers, including prostate, kidney and testicular cancers.

“Our knowledge of PFAS toxicity has increased over time. Recent research on immunotoxicity has pushed drinking water regulations even lower than before. Long-term low-level exposure to certain PFAS can make it more difficult for humans to build antibodies after being vaccinated again for various diseases, “she added.

This phenomenon is particularly problematic in a country like India, with a long history of rainwater harvesting. In fact, some parts of the country have begun to impose the collection of rainwater. For example, the Tamil Nadu government has ordered all government, commercial, educational and residential complexes to set up state-approved rainwater harvesting facilities in their buildings. According to the new study, rainwater collected in the country may not be fit for human consumption.

“There are fairly simple cleaning methods to remove PFAS such as activated carbon filtration, but cleaning water at very low levels in the guidelines is challenging and expensive. Activated carbon will need to be renewed regularly and old contaminated material destroyed, ”Cousins ​​explained.

While the demand for expensive rainwater filtration methods is troubling in itself, there is an even bigger problem. Until recently, it was commonly believed that PFAs would eventually be washed out in the oceans where they would be diluted. But the results of another recent study indicate that some PFAs can be transported back into the atmosphere as part of marine spray aerosols. This could mean that PFAs could be constantly cycled through the hydrosphere, leading to their continued presence to contaminate rainwater, freshwater bodies and surface soils.

Leave a Reply

Your email address will not be published. Required fields are marked *