It's no exaggeration to say that donating blood can save lives. Now, researchers have found a curious benefit for the donor: regular trips to the blood bank appear to reduce the amount of certain 'forever chemicals' swimming around in the bloodstream.

While scientists aren't sure just how dangerous these widely used perfluoroalkyl and polyfluoroalkyl substances (PFAS) might be, they are sometimes referred to as forever chemicals because they tend not to degrade in nature.

The researchers tested 285 firefighters working at the ​​Fire Rescue Victoria service in Australia, who donated both blood and plasma over the course of 12 months. Firefighters are routinely exposed to PFAS via firefighting foam, and typically have higher levels in their blood than the general population.

"The results from the study show both regular blood or plasma donations resulted in a significant reduction in blood PFAS levels, compared to the control group," says haematologist Robin Gasiorowski, from Macquarie University in Australia.

"While both interventions are effective at reducing PFAS levels, plasma donations were more effective and corresponded to a 30 percent decrease."

It's the first time that a way of reducing PFAS in the blood has been found – and it's all down to an act of charity that benefits society, rather than any kind of drug treatments or complicated procedures that need to be carried out in hospitals.

For the duration of the study, 95 firefighters gave blood every 12 weeks, 95 firefighters gave plasma every 6 weeks, and 95 firefighters didn't make any blood or plasma donations. Levels of PFAS in the latter group remained unchanged.

It would appear that because PFAS bind to serum proteins in the blood, reducing the amount of that blood component can, over time, reduce the levels of PFAS. However, it's early days for the research, and a lot more analysis on bigger groups of people is needed.

"While this study did not examine health effects of PFAS or the clinical benefits of its reduction in firefighters, these important questions are worthy of further research to better understand health outcomes from exposure and treatment," says environmental scientist Mark Taylor, from Macquarie University.

PFAS are by no means only a problem for firefighters. They can be found in everything from paints to pans, and have been preliminarily linked to health problems including obesity, diabetes, and certain types of cancer.

Not only are these chemicals seeping into our bodies, they're also reaching some of the most remote places on Earth. As their nickname suggests, these substances will be around for a very long time, so we need to know more about what we're dealing with.

These first results are promising, and the next step is to run tests on more diverse groups to see if there are particular categories of people at risk who might benefit most from the plasma and blood donation processes.

"Firefighters often put the health and safety of others before their own health, so it is pleasing that the results from this research can be used to improve the health of firefighters who have acquired high PFAS levels through vital community work," says Mick Tisbury, Assistant Chief Fire Officer at Fire Rescue Victoria.

"It's important to also recognize the firefighters who volunteered their time to participate in this important study. The findings will not only benefit the firefighting community but others working in high-risk sectors who are exposed to PFAS chemicals."

The research has been published in JAMA Network Open.