Drinking Water Regulation • National Primary Drinking Water Regulations: Legally enforceable (<100 regulated contaminants) • Regulation Creation Steps: 1. Add the compound to the “Contaminant Candidate List” 2. Make a “Regulatory Determination” • Possible harm to human health • High level of exposure (Unregulated Contaminant Monitoring Rule (UCMR)) • Administrator decides regulation will reduce risk 3. Set a “Maximum Contaminant Level Goal ” which is non- enforceable 4. Set the standard called a “Maximum Contaminant Level (MCL)”
Maximum Contaminant Level (MCL) • MCL = (Reference Dose x Relative Source Contribution x Body Weight) ÷ Intake Rate • RFD: Reference dose calculated using no adverse effect levels in studies where mammals were dosed orally https://www.wsj.com/articles/with‐ drinking‐water‐safe‐enough‐is‐the‐ epas‐goal‐1457702107
PhD (Environmental Engineering): Per- and Polyfluoroalkyl Substances (PFAS) in Municipal Solid Waste and Landfill Leachate.
ORISE Postdoc at the EPA, NC Mark Strynar and Andy Lindstrom: EPA chemists measuring PFAS and other compounds with mass spectrometry Neil Chernoff and Donna Hill: EPA toxicologists working on the toxins produced from harmful algal blooms
Epidemiology Toxicity Testing In Vitro In Vivo • Difficult to • Used for drinking interpret water reference • Cannot be used to • Exposed doses set drinking water without • Established reference doses consent methods for • Unclear how relates relating to humans to humans
You can’t have your cake and eat it too…. In Vitro In Vivo Required to regulate EPA research focus Before we ban animal testing, regulators need to establish a new method for regulating chemicals in drinking water!!!
Wilmington, NC GenX: PFOA alternative GenX PFOA (C8)
NCSU Study on Wilmington, NC’s Drinking Water • Red is GenX in both graphs • PFAS in the bottom graph are byproducts of manufacture without standards Sun et al. 2016
TSCA Loophole for Industrial Byproducts 40 CFR § 720.30 - Chemicals not subject to notification requirements: • The chemical substances described below: (1) Any impurity (2) Any byproduct which is not used for commercial purposes (8) Any non-isolated intermediate
NCSU CHHE Study in Wilmington, NC Dr. Nadine Kotlarz • The four PFAS in the blood are byproducts of manufacture (not products) and therefore are not regulated under TSCA https://chhe.research.ncsu.edu/wordpress/wp‐content/uploads/2018/11/Community‐ event‐BLOOD‐slides.pdf
EPA’s PFAS Action Plan • EPA issued this action plan in response to public pressure about PFAS • Long Term Action: “Generate PFAS toxicology data through new approaches such as high throughput screening, computational toxicology tools, and chemical informatics for chemical prioritization, screening, and risk assessment” • “The EPA plans to generate additional PFAS toxicity data through in vitro high throughput toxicity testing (HTT) and high throughput toxicokinetic (HTTK) assays to inform hazard effects characterization and promote prioritization of chemicals for further in vivo testing” https://www.epa.gov/sites/production/files/2019‐ 02/documents/pfas_action_plan_021319_508compliant_1.pdf
Conclusions • Byproducts of industrial chemical manufacture should be regulated • The current system for regulating contaminants in drinking water is taking way too long • Regulators need in vivo data to set drinking water limits for a compound • If we send soldiers into battle to protect us, then why not sacrifice a few mice for protection? Required to regulate EPA research focus
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