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Human Health 2 Establishing Thresholds

Human Health 2 Establishing Thresholds. Establishing Water Quality Thresholds (Q1). Epi Studies. Toxicology Studies. Analytical Methods. Exposure Assessment. Process. Persistence (Fate and Transport). Uncertainty. Occurrence Data (inc. degradates). Temporal. Risk Communication.

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Human Health 2 Establishing Thresholds

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  1. Human Health 2Establishing Thresholds

  2. Establishing Water Quality Thresholds (Q1) Epi Studies Toxicology Studies Analytical Methods Exposure Assessment Process Persistence (Fate and Transport) Uncertainty Occurrence Data (inc. degradates) Temporal Risk Communication THRESHOLD (Health Reference Level)

  3. Thresholds Depend Upon Exposure (Q2) • Indirect Potable Reuse - Groundwater • IPR - Surface Water Augmentation • Surface Water Discharge • Downstream Drinking Water • Bioaccumulation • Non-potable Reuse • Ocean Desalination b

  4. What Process For Establishing Water Quality Thresholds DLR HRL (PHG) Set DLR DLR<PHG DLR<PHG Set PHG CommunicateRIsk CommunicateRIsk b

  5. Thresholds Depend Upon Exposure (Q2) • Indirect Potable Reuse - Groundwater • IPR - Surface Water Augmentation • Surface Water Discharge • Downstream Drinking Water • Bioaccumulation • Non-potable Reuse • Ocean Desalination b

  6. Temporal Issues (Q2&Q3) • Acute Exposure vs. Chronic Exposure – compound specific • May have acute and chronic criteria • Acute criteria will drive monitoring frequency b

  7. Ongoing Projects Doing This Already • WRF/WRF Toxicological Relevance (05-005) • WRF Research Needs (Cotruvo/Bull) • WRF IEUA Health Based (Nellor) • Intertox Tox Relevance (WRF) • NRC Panel

  8. There are Known Knowns and Unknown Knowns Uncertainty & Conservatism = f(lack of information)

  9. Uncertainty Drives Threshold Conservatism (Q4) • Standard EPA Uncertainty Factors Can be Applied to Balance Lack of Data b

  10. Risk Communication • Uncertainty is Reality • Other Routes of Exposure? • Open Discussion with the Public • Work to Fix Problem • …try to avoid these issues through intermediate monitoring

  11. What if You Exceed HRL? • Retest, split samples, document outlier or repeated event. • Running averages to document risk • acute versus chronic

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