PFAS pollution lowers sperm count in mice, alters their embryos: study

19 hours ago 3

Short-term exposure to a cocktail of forever chemicals at the same levels found in the environment could disrupt hormones and sperm counts in male mice and cause abnormalities in their embryos, an Australian study has found.

The research by the University of Newcastle is believed to be the first animal testing done on environmentally relevant levels of per- and polyfluoroalkyl substances (PFAS), a family of synthetic chemicals that has emerged as a major environmental pollutant, particularly because of its historical use in firefighting foam.

Co-author Dr Jacinta Martin said the research, which was published on Tuesday night in the journal Communication Biology, based the levels and exact mix of PFAS types on water samples taken from a well at the Williamtown contamination site near Newcastle.

Professor Brett Nixon and Dr Jacinta Martin from the University of Newcastle have studied the effect of PFAS exposure on mice.

Martin said the decision to use a real-world profile of PFAS pollution was intended to cut through the debates about conflicting scientific literature and the argument by state health authorities that the chemicals are heavily diluted in the environment and therefore not a risk to public health.

“If we can take away all the excuses that [research] doesn’t perfectly mimic what’s going on outside, then maybe what we could find might help fill that gap, and we’ll be able to better actually provide information or knowledge to these individuals who are making these big decisions,” Martin said.

“In terms of it being diluted, it depends on where you’re getting it because not only could you be exposed in the environment, but you could be exposed from your workplace, from the things that we’re buying in the shop, a non-stick pan or waterproof clothing, for example. You wouldn’t necessarily just be getting it from that one source.”

The work backs up global retrospective analysis that suggests PFAS can disrupt human fertility, including reduced hormones and sperm count, but also reveals a potential new avenue of harm – that paternal PFAS exposure alone could have consequences for children, even if the children themselves are not directly exposed.

The researchers used the sperm from the exposed male mice to fertilise eggs from females that had not been exposed, and these early embryos showed abnormal gene expression that could affect birth weights.

Martin said laboratory modelling usually focused on one PFAS type at a time, but the Williamtown sample included nine PFAS types, including the three most commonly detected in humans – PFOS, PFHxS and PFOA.

The Newcastle study also included a high-dose group of mice exposed to PFAS at 10 times the Williamtown concentration, but some of the hormonal effects were only observed in the low-dose group that matched Williamtown. The paper notes that non-linear dose responses have been observed in numerous studies of endocrine-disrupting chemicals.

Dr Jacinta Martin co-authored a paper on the effects of PFAS on mice fertility.

The Australian Bureau of Statistics has found that almost everyone in Australia has some level of PFAS in their bloodstream, and three types – PFOS, PFHxS and PFOA – have been detected in 85 per cent of people over the age of 12. Numerous Australian and global studies have found that many types of PFAS cause cancer and birth defects, and the National Health and Medical Research Council lowered the levels of contamination permitted in drinking water earlier this year.

The chemicals build up in the body over time, but the Newcastle researchers found significant effects in the mice even over the 12 weeks of the study. Some of the changes were a fall in male hormones, including testosterone and dihydrotestosterone, which are vital for sperm production and are linked in other research to mood changes, muscle loss and fat gain.

The effects also included a decrease in day-to-day sperm production, meaning the mice were less fertile. The sperm looked normal and could fertilise eggs, but carried hidden changes in the form of altered molecules that regulate gene expression.

Dr Jacinta Martin analyses results on a computer.

The researchers received funding from the NHMRC’s targeted call for research into PFAS.

The study also has implications for wildlife, especially predators such as snakes, aquatic creatures such as frogs, and platypus.

University of Melbourne researchers have separately investigated PFAS in marsupials for the first time, and that paper will be published in Science of the Total Environment later this week.

They found high PFAS concentrations in common ringtail and brushtail possums that had died for other reasons in Melbourne. The possums studied had at some point been exposed, and the median levels were among the highest recorded in any small terrestrial mammal worldwide. The researchers said this suggests that broad PFAS contamination of Australian ecosystems and native species is highly probable.

Western Sydney University water scientist Professor Ian Wright, co-author of the PFAS in platypus study, said it was fascinating that results from a study by the University of Newcastle were based on just 12 weeks.

“It really makes you wonder about what happens with a lifetime exposure,” Wright said. “This has so many questions about fertility and survival of a species, but it is concerning there is [genetic] alteration, so we could see effects in future generations that we just don’t understand yet.”

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