Research shows that PFAS and microplastics become more toxic in combination
Few man-made substances are individually as ubiquitous and dangerous as PFAS and microplastics, and when they join forces there is a synergistic effect that makes them even more toxic and pernicious. new research suggests.
The study authors exposed water fleas to mixtures of the toxins and found that they had more serious health consequences, including lower birth rates and developmental problems such as delayed sexual maturity and stunted growth.
The increased toxic effects are cause for alarm because PFAS and microplastics are researched and regulated separately, but people are almost always exposed to both. The study also found that fleas previously exposed to chemical pollution were less able to withstand the new exposure.
The findings “underline the critical need to understand the impact of chemical mixtures on nature and human health,” wrote the study authors, based at the University of Birmingham in the United Kingdom.
PFAS are 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 build up, and are linked to cancer, kidney disease, liver problems, immune disorders, birth defects and other serious health problems.
Microplastics are small pieces of plastic that are deliberately added to products or excreted from plastic goods as they deteriorate. They are found throughout the human body and can cross the blood-brain barrier. Research has linked them to developmental damage, hormone disruption, cardiovascular disease and other health problems.
Plastic is often treated with PFAS, which can cause microplastics to 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 are very sensitive to chemicals and are therefore often used to study ecological toxicity.
Both groups were exposed to pieces of PET, a common microplastic, and to PFOA and PFOS, two of the most common and dangerous PFAS compounds. The mixture reflected conditions common in lakes around the world.
The study authors found that the mixture is more toxic than PFAS and microplastics separately. They attributed about 40% of the increased toxicity to a synergy between the substances that makes them even more dangerous. The authors theorized that the synergy involves the interaction between the charges of microplastics and PFAS compounds.
The remainder of the increased toxicity was attributed to the 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 maturation and showed delayed sexual growth.
The observed effects “significantly improve” the understanding of exposure to multiple chemicals and substances, the authors wrote.
“It is imperative to continue investigating the toxicological effects of these substances on wildlife to support regulatory and conservation efforts,” they said.