(CHEMICAL WATCH) Kelly Franklin, June 29, 2018 — The US Agency for Toxic Substances and Disease Registry has released a controversial draft toxicological profile on four per- and polyfluoroalkyl substances (PFASs). The move comes amid uproar over allegations that other federal agencies were suppressing its release.
Last month, internal EPA emails released under a public records request showed concern that the ATSDR was planning to publish a study with minimal risk levels (MRLs) for the PFASs far below those set by the EPA. One White House staffer feared this would result in a “public relations nightmare“.
Congress and the consumer advocacy community responded with outrage over the delay, and called for the ATSDR – which is housed under the US Department of Health and Human Services (HHS) – to release the draft toxicological profile.
Now the “very, very low” MRLs values referenced in the January email exchange have been confirmed in the toxicological profile for four of the 14 assessed substances: PFOS, PFOA, PFHxS, and PFNA.
The limits are set out on a body-weight basis (mg/kg/day), intended to serve as estimates of daily human exposure unlikely to cause an appreciable risk of adverse non-cancer health effects.
Environmental Working Group researchers tell Chemical Watch that using the EPA’s methodology for translating these figures into drinking water advisory values results in the following levels:
- PFOS: approximately 7 parts per trillion (ppt);
- PFOA and PFNA: approximately 11ppt; and
- PFHxS: approximately 74ppt.
This contrasts with the EPA’s non-enforceable lifetime health advisory level for PFOA and PFOS of 70ppt in drinking water. This makes its level seven to ten times higher than that recommended by the ATSDR, says the EWG.
And it “confirms that the EPA’s guidelines for PFAS levels in drinking water woefully underestimate risks to human health,” said Olga Naidenko, senior science adviser at the group.