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Kim A. Schwab - 4 - Is 17 Augu=t 1998 Notes: 1) Primary MCLs are health based, but also reflect other factors relating to technologic and economic feasibility of attainment and monitoring in a water distribution system and at the tap,not necessarily in the water resource. 2) Derived from oral cancer potency factor published by the California Environmental Protection Agency, Office of Environmental Health Hazard Assessment, assuming 2 liters/day water consumption and 70 kg body weight. 3) Federal Register, Vol. 54,No. 97,pp. 22138,22139. 4) Health advisory=4000µg/1 for 10 day exposure or less. No lifetime exposure advisory has been developed. However, lifetime health advisories are normally at least ten-fold lower than 10-day advisories. Therefore, a level of 400 gg/l would be a reasonable estimate of a lifetime protective level for n-hexane. 5) Health Advisory. Document states that the 100 gg/I level should be health protective for 10 days of exposure or less. No lifetime exposure advisory has been developed. However, lifetime health advisories are normally at least ten-fold lower than 10-day advisories. Therefore, a level of 10 9g/1 would be a reasonable estimate of a lifetime health protective level for diesel or kerosene. 6) McKee&Wolf,Water Quality Criteria, 2nd Ed., State Water Resources Control Board(1963, 1978)p. 230. 7) Liability under Proposition 65 may also exist for responsible parties where levels in water exceed 0.25 gg/l. 8) Also know as 1,2-dichloroethane. 9) Based on benzo(a)pyrene;see 22 CCR §12000(Proposition 65) for list of carcinogens; criteria for individual PAHs may be calculated by dividing cancer risk level by weighting factors (PEFs)in the table on the following page. 10) National Ambient Water Quality Criteria. 11) Integrated Risk Information System; listed value assumes 2 liters/day water consumption, 70 kg body weight, and 20%relative source contribution from drinking water. 12) J.E. Amoore and E.Hautala, Odor as an Aid to Chemical Safety: Odor Thresholds Compared with Threshold Limit Values and Volatilities for 214 Industrial Chemicals in Air and Water Dilution,Journal of Applied Toxicology, Vol. 3,No. 6(1983).