Paul Nathanail talks about PFAS at Geotechnica 2023
Paul Nathanail gave a slightly different 'presentation' on PFAS at this year's Geotechnica - he asked for questions first.
Some came from LinkedIn and others via SMS from the headphone-wearing "silent disco" audience on the day.
Here's a selection:
Q: What is known about the prevalence of PFAS in the environment?
A: Because PFAS were widely used and are persistent they are widespread in the environment. BGS is doing a project on ambient concentrations of PFAS in soil using archived samples collected some time ago for work to explore baseline concentrations of metals in soil.
Q: Are there any of them volatile and considered a vapour intrusion risk.
There are over 12,000 PFAS listed by the US EPA and well over 6 million that meet the OECD definition. Some PFAS are gases and some are volatile liquids but these are not reported as having been widely encountered in soil.
Q: Will I die from the Teflon on my saucepans at home?
A: You would need to heat the pan up to high temperatures - several hundreds of degrees centigrade - to begin to break down the coating and release fumes that have been linked with "polymer fume fever", but if the Teflon is flaking off, it's time to get a new saucepan.
Q: How commonly do you think regulators are asking for PFAS to be considered if not identified in ground investigation reports, and perhaps should have been?
A: Regulators are expecting PFAS to be considered. Their awareness now is much greater but fluorinated surfactants were flagged up as contaminants in the 1994 vintage DoE Industry Profiles. We're going beyond airports, fire stations and military bases. There is a new CL:AIRE bulletin that signposts where PFAS may have been used, and CIRIA's PFAS guidance, including a detailed list of industrial processes using PFAS, is coming soon.
A detailed preliminary risk assessment is invaluable in establishing where and when PFAS may have been used and for what purpose - pointing to what mixture of PFAS might be present as contamination in soil or water.
Q: Are there any UK PFAS screening values?
A: There are soil screening values for ecological risk for PFOS and PFOA. There are also values for water environments.
And for human health? Not yet; but you could come to LQM's PFAS GAC course, 25/26 July and learn how to derive your own.