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Case Study

Oral Reference Dose for Perfluorohexanoic Acid

By Judi L. Durda, Chief Strategy Officer


Prompted by health concerns, industry phased out long-chain per- and polyfluoroalkyl substances (PFAS), replacing them with short-chain PFAS for their more favorable toxicity profiles. Short-chain PFAS are nevertheless being scrutinized amid concerns that they too could pose similar risks. Perfluorohexanoic acid (PFHxA) is a short-chain perfluoroalkyl acid that that can form through degradation of many different short-chain PFAS. Therefore, understanding whether PFHxA poses a risk to human health can be informative for other short-chain PFAS chemistries.


We conducted a comprehensive literature review to identify all available toxicology studies for PFHxA and used those studies to derive a chronic oral reference dose (RfD). We then conducted a human exposure and risk assessment. By comparing current human exposure levels to the RfD, we demonstrated that PFHxA poses minimal risk to human health.


We published a pair of peer-reviewed journal articles summarizing the results of our hazard, dose-response, exposure, and risk assessments. Our publications are now the basis of the health-based drinking water value proposed by Michigan for PFHxA in April 2019.

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Key Contact

Judi Durda is a toxicologist and ecologist with more than 30 years of experience in the health and environmental science... Full bio

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