Few man-made substances are as individually ubiquitous and dangerous as PFAS and microplastics and when they join forces there is a synergistic effect that makes them even more poisonous and destructive, new research suggest
The authors of the study exposed water fleas to mixtures of the toxic substances and found that they had worse health effects, including lower birth rates and developmental problems, such as delayed sexual maturity and stunted growth.
The enhanced toxic effects raise alarm because PFAS and microplastics are researched and regulated in isolation from each other, but people are almost always exposed to both. The research also showed that those fleas previously exposed to chemical pollution were less able to withstand the new exposure.
The findings “underscore the critical need to understand the impact of chemical mixtures on wildlife and human health,” wrote the study’s authors, who are at the University of Birmingham in the United Kingdom.
PFAS is a class of about 15,000 compounds typically used to make products that resist water, stains and heat. They are called “forever chemicals” because they do not break down naturally and accumulate, and have been linked to cancer, kidney disease, liver problems, immune disorders, birth defects and other serious health problems.
Microplastics are small pieces of plastic that are either intentionally added to products or shed by plastic goods as they degrade. They are found throughout human bodies and can cross the blood-brain barrier. Research has linked them to developmental damage, hormone disruption, cardiovascular disease and other health issues.
Plastics are often treated with PFAS, so microplastics may contain the chemical.
Researchers compared a group of water fleas that had never been exposed to pollution with another group that had been exposed to pollution in the past. Water fleas have high sensitivity to chemicals, so they are frequently used to study ecological toxicity.
Both groups were exposed to bits of PET, a common microplastic, as well as PFOA and PFOS, two of the most common and dangerous PFAS compounds. The mix reflected conditions common in lakes around the world.
The study’s authors found the mixture to be more toxic than PFAS and microplastics in isolation. They attributed about 40% of the increased toxicity to a synergy between the substances making them even more dangerous. The authors theorized the synergy has to do with the interplay in the loads of microplastics and PFAS compounds.
The remainder of the increased toxicity was attributed to simple addition of their toxic effects.
Fleas exposed to the mixture showed a “significantly reduced number of offspring,” the authors said. They were also smaller at maturity and showed delayed sexual growth.
The effects they observed “significantly” advance the understanding of exposure to multiple chemicals and substances, the authors wrote.
“It is imperative to continue to investigate the toxicological impact of these substances on wildlife to inform regulatory and conservation efforts,” they said.
