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UPDATE ON HEALTH CRITERIA VALUES

UPDATE ON HEALTH CRITERIA VALUES. Frances Pollitt Health Protection Agency. What are HCVs?. The level of long-term human exposure to a chemical contaminant in soil which is considered either to pose no appreciable risk, or a minimal risk, to health.

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UPDATE ON HEALTH CRITERIA VALUES

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  1. UPDATE ON HEALTH CRITERIA VALUES Frances Pollitt Health Protection Agency

  2. What are HCVs? • The level of long-term human exposure to a chemical contaminant in soil which is considered either to pose no appreciable risk, or a minimal risk, to health. • Established from a review of available animal and human data. • Human exposure at or below the HCV is unlikely to represent a significant possibility of significant harm. • Human exposure above the HCV might represent a significant possibility of significant harm, with the significance linked to the margin of exceedance, the duration and frequency of exposure, and other factors that the enforcing authority may wish to take into account.

  3. Chemicals for which new HCVs are available • BTEX: benzene, toluene, ethylbenzene, xylenes. • Metals: mercury, selenium, arsenic, nickel, cadmium. • Other: phenol, dioxins.

  4. BTEX

  5. Metals I

  6. Metals II

  7. Organic compounds

  8. Why have some HCVs changed? • New or better scientific information so less uncertainty about the toxicity of chemical • Change in the expert view on the same dataset • Change for non-scientific reasons

  9. New or better scientific information • Toluene Main health concern is neurotoxicity. Old HCVinh [74 μg/kg bw/day]: based on WHO Air Quality Guideline for Europe, which was derived from results of one small occupational study. New HCVinh [1400 μg/kg bw/day]: based on extensive review of occupational studies by US EPA in 2005 which identified a number of new studies and clarified the dose-response for neurotoxicity.

  10. New or better scientific information • Cadmium Critical effects are on the kidney, where it accumulates. Old HCVoral [1 μg/kg bw/day]: based on an old guideline considered “imprecise”. New HCVoral [0.36 μg/kg bw/day]: based on recent review by European Food Safety Authority, including many recent studies. TDI derived from the estimated cadmium intake at which 95% of population would be protected against signs of early kidney damage. Considered conservative by COT.

  11. Change in the view on the same dataset • Elemental mercury Main health concern is neurotoxicity following inhalation of mercury. Old HCVinh [0.3 μg/kg bw/day]: based on WHO Air Quality Guideline for Europe, which was derived from results of occupational studies. New HCVinh [0.06 μg/kg bw/day]: also derived from occupational studies but based on more conservative but more defensible assessments by ATSDR and IPCS.

  12. Change in the view on the same dataset • Selenium Long-term exposure can cause selenosis: changes to hair and nails, skin and neurological effects. Old HCVoral [5 μg/kg bw/day]: based on findings from China. No adverse effect level for mild selenosis, recommended by several international bodies. New HCVoral [6.4 μg/kg bw/day]: based on same studies but recent interpretation by Expert Group on Vitamins and Minerals. Chronic exposure to twice this level may lead to mild selenosis

  13. Change for non-scientific reasons • Benzene Old HCVinh [0.91 μg/kg bw/day] : based on the target standard for benzene in air recommended by EPAQS, which was based on “no observed effect level” in an occupational study New HCVinh [1.4 μg/kg bw/day] : not health-based but based on Air Quality Objective for E&W. This was adopted to avoid disproportionately targeting exposures from soil.

  14. Cadmium - HCVinh • Some evidence that it is genotoxic: unclear whether thresholded or not. Inhaled cadmium causes lung cancer in rats; some evidence of lung cancer in workers. • Old and new HCVinh [0.001 and 0.0014 μg/kg bw/day]: both based on a 2000 assessment which used results of an occupational study to identify an atmospheric concentration which would not cause kidney injury. These are TDIs. • LQM HCVinh [0.001 μg/kg bw/day]: an Index Dose.

  15. Phenol - HCVinh • New HCVinh [10 μg/kg bw/day]: based on 2006 EU Risk Assessment Report and derived from limited occupational data in which the critical endpoint was liver toxicity. This is a TDI. • Does not account for phenol’s genotoxic potential, which for inhalation is presumed to have no threshold. • LQM HCVinh [(700) μg/kg bw/day]: based on route-to-route extrapolation and comparison with the HCVoral

  16. Coming soon • TOX Reports for: • Chromium • Cyanide • Lead • Polycyclic aromatic hydrocarbons (PAHs)

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