title: Derivation of a drinking water equivalent level (DWEL) related to the maximum contaminant level goal for perfluorooctanoic acid (PFOA), a persistent water soluble compound.
abstract: Water soluble compounds persistent in humans and the environment pose a challenge for estimating safe levels in tap water. A viable approach to estimate a drinking water equivalent level (DWEL) for perfluorooctanoic acid (PFOA) was applied to its extensive relevant information from human and laboratory animal studies. PFOA has been identified at 3.5 microg/L (mean) in tap water in proximity to a manufacturing facility; however, in most supplies, the levels were below 7.5 ng/L (usual limit of detection). PFOA has an average half-life in humans of 3.5years. From animal studies, PFOA is considered a possible hepatotoxicant and developmental toxicant for humans. Based on two chronic studies, PFOA was judged to be a possible human carcinogen, whose mode-of-action was likely to be related to receptor activation but not genotoxicity. The Benchmark Dose-Uncertainty Factor approach was selected for dose-response for noncancer and cancer. Based on internal dose of PFOA, the DWEL protective against cancer is 7.7 microgPFOA/L tap water, and the noncancer DWELs range from 0.88 to 2.4 microg/L. These DWELs can be considered a reliable, albeit conservative, basis to set a Maximum Concentration Level Goal under the US Safe Drinking Water Act.
authors.affiliation: The Sapphire Group Inc, 3 Bethesda Metro Center, Bethesda, MD 20814, United States. rgt@thesapphiregroup.com
authors.forename: Robert G
authors.initials: RG
authors.lastname: Tardiff
authors.forename: M Leigh
authors.initials: ML
authors.lastname: Carson
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Sweeney
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Kirman
authors.forename: Yu-Mei
authors.initials: YM
authors.lastname: Tan
authors.forename: Melvin
authors.initials: M
authors.lastname: Andersen
authors.forename: Christopher
authors.initials: C
authors.lastname: Bevan
authors.forename: Michael L
authors.initials: ML
authors.lastname: Gargas
mesh_terms: D000818:Animals; D002210:Caprylates / Q000032:analysis*; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects*; D004784:Environmental Monitoring / Q000379:methods*; D005466:Fluorocarbons / Q000032:analysis*; D006801:Humans; D019055:No-Observed-Adverse-Effect Level; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis* / Q000592:standards
chemical_list: D002210:Caprylates; D005466:Fluorocarbons; D014874:Water Pollutants, Chemical; C023036:perfluorooctanoic acid