SITE INFORMATION AND CORRESPONDENCE 1980-1999

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• permit conditions, 6. Discharger's local limits are inadequate, 7. permit fails to discuss trihalomethanes, and 8. information sheet needs to clarify how trucked wastes are handled. Our detailed comments are as follows: I. THE ABSENCE OF MASS LIMITS IN THE PERMIT IS INCONSISTENT WITH FEDERAL REGULATIONS No mass limits are proposed in the permit despite Clean Water Act regulations requiring that "[a]ll pollutants limited in permits shall have limitations, standards or prohibitions expressed in terms of mass . . ." with a few, inapplicable exceptions. 40 C.F.R. § 122.45(f). A. The Permit Must Include A Water Quality Mass-Based Limit For Mercury. The entire Delta is listed on the 1998 California 303(d)List as impaired because of mercury. There are long-standing fish consumption advisories for striped bass and sturgeon in the Delta because of mercury contamination. Federal regulations prohibit increases in mass loading of pollutants identified as contributing or causing impairment pending development of a TMDL. A concentration and mass limit for mercury must be included in the permit. The existing EPA Ambient Water Quality Criteria continuous concentration(4-day average)is 0.012µg/1. The final California Toxic Rule numerical criteria for mercury is uncertain but is likely to be substantially more restrictive than the 0.050µg/1 EPA initially proposed. EPA proposed criteria failed to consider the long-term residual bioaccumulative effects of short-term elevated concentrations of mercury in water. We understand that the Regional Board submitted formal comments to EPA opposing the proposed California Toxics Rule change in the mercury objective. The US Fish and Wildlife Service and the National Marine Fisheries Service,in their draft biological/conference opinion on the proposed California Toxic Rule,characterized the EPA proposed criteria as jeopardizing the continued existence of numerous species listed under the federal Endangered Species Act. Based on a review of the scientific literature,the Services proposed a Reasonable and Prudent Alternative for mercury of 2.0 ng/1 (0.002µg/1) on a total unfiltered basis to protect listed amphibians and birds. They further proposed that present standards be continued for fish until the EPA could promulgate numeric aquatic life criteria which would consider the bioaccumulative nature of mercury and the long-term persistence of mercury in aquatic sediments and food chains, and the potential for maternal transfer of methyl mercury to eggs and young for water bodies DeltaKeeper,Tentative NPDES Permit,Lodi, 17 December 1999,Page 2.