Not all PFAS are created equal

While in Wellington last week for the SETAC conference, I hosted a session on emerging contaminants. Then afterwards I was approached by a UK journalist to look at some data they had on PFAS in urban environments and it got me thinking about the PFAS group of chemicals. Here is what the European Environment Agency has to say about them:

“Comprising more than 4 700 chemicals, perfluorinated and polyfluorinated alkyl substances (PFAS) are a group of widely used, man-made chemicals that accumulate over time in humans and in the environment. They are known as 'forever chemicals' as they are extremely persistent in our environment and bodies”.

But there are some that are more worrying than others. So I created a portfolio of some PFAS chemicals using our software and sure enough it shows a spread of toxicity and persistence in the environment. But how does that compare to some other well known goodies and baddies?

Next I added DDT and ethanol to the portfolio. I wanted to see how the PFAS group compared to a product we’ve banned globally because it’s a well known baddie (DDT) and to a chemical that has the US EPAs green circle of approval under The Safer Choice of the U.S. Environmental Protection Agency (EPA), which “helps consumers, businesses, and purchasers find products that perform and are safer for human health and the environment”.

The results of the analysis are shown in the graphic with this blog post. The bubble size represents how much exposure these products are getting in published literature over the last five years. When I toggle the graph to show chemicals of emerging concern (not shown here), ethanol has no bubble at all, but PFOA, PFHxS and PFOS all indicate their role as persistent “forever chemicals”.

I welcome dialogue on the topic. We obviously need to prioritise which ones we mitigate first, and do some communication with the public about the relative risks from PFAS chemicals, as they are not all created equal.