SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

RESPONSE TO WRITTEN COMMENTS 15- City Of Stockton-Regional Wastewater Control Facility NPDES No. CA0079138 26 April 2002 Board Meeting detectable"requirements, the permit used a minimum detection limit consistent with the Minimum Levels in the State Implementation Plan and with the Basin Plan prohibition. The pesticide narrative objective has been in the Basin Plan since before 1977. Therefore, according to the Basin Plan and EPA regulations, the Regional Board could not include a compliance schedule in the permit. The Regional Board must require immediate compliance or provide a compliance schedule in a cease and desist order. However, the Regional Board recognized that the detection limit for total identifiable persistent chlorinated hydrocarbon pesticides has decreased since the objective was adopted into the Basin Plan. The Regional Board, therefore, determined that the application of the current detection limit [the "Minimum Levels" listed in Appendix 4 of the SIP] could be considered a new interpretation of the objective. Under that circumstance EPA allows the use of compliance schedules within the permit to achieve compliance with the objective. The Basin Plan was legally adopted in accordance with Water Code Section 13241 and the water quality objective for pesticides, contained in the existing Basin Plan, is not a new objective, therefore, the Regional Board is not required to conduct a new evaluation of the factors in Water Code Section 13241 every time the objective is applied in an NPDES Permit. Stockton Comment No. IV.D(3) (Mercury): The proposed mercury limits are unduly restrictive and unsupported in that the Findings fail to demonstrate that the current CTR objective for mercury is, in fact, under-protective. The mercury fish tissue information used to justify the Section 303(d) listing reflects historical loadings of mercury that were higher than present loadings. There is no information presented in the record showing that the current mercury level in the Delta presents a fish tissue contamination issue not otherwise appropriately regulated by the CTR objective. RWQCB Response: This comment is adequately addressed in Finding 30 and Section 11.1 of the Fact Sheet. In addition, the Department of Health Services has issued a health advisory for human consumption of fish from the Delta, due to concentrations of mercury, PCBs and other chemicals. Stockton Comment No.IV.D(4) (Interim Limits —Mercury, Endrin, DDT, Lindane): The Board's proposed interim limits are unduly restrictive and will improperly preclude already authorized local growth, contrary to state law. As discussed in the Napa decision, interim limits should not result in a freeze on local growth while the TMDL process is underway. The development of interim limits should conform to the adopted procedures in the SIP. With respect to mercury and other constituents for which interim mass limits are proposed, the tentative order would require development of an "offset"program. Authority for such a program is lacking. RWQCB Response: The proposed permit includes an offset program for mercury. Providing that the City is in compliance with the terms of the compliance schedules in Provisions G.1, G.F. G.7, and G.8, actual mass loadirif L11Oye or below the interim mass limitatior -�r rr ercury cap he "b d" until such time a discharge specific offset program is adopted by the . egi, al Board into the )rder to