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REGIONAL BOARD RESPONSE (SWRCB10CCFILEA-1634) - 4 - <br /> PETITION <br /> 4 - <br /> PETITION FOR REVIEW OF WASTE DISCHARGE REQUIREMENTS <br /> ORDER NOS. R5-2004-0028 AND R5-2004-0029 <br /> CITY OF MANTECA WATER QUALITY CONTROL FACILITY <br /> including state narrative criteria for water quality." (the "reasonable potential analysis"). With <br /> respect to narrative objectives,the Regional Board must establish effluent limitations using one <br /> or more of three specified sources, including USEPA's published water quality criteria(40 CFR <br /> 122.44(d)(1)(vi)(A), (B), or(C)). See American Iron &Steel Institute v.EPA (D.C. Cir. 1997) <br /> 115 F.3d 979, 990. This requirement applies to narrative criteria as well as to criteria specifying <br /> maximum amounts of particular pollutants. In addition, the Regional Board's Basin Plan <br /> contains an implementation policy("Policy for Application of Water Quality Objectives")that <br /> specifies that the Regional Board "... will, on a case-by-case basis, adopt numerical limitations <br /> in orders which will implement the narrative objectives." (Basin Plan p. IV-17.00). It also states <br /> that the Regional Board will consider"... relevant numerical criteria and guidelines developed <br /> and/or published by other agencies and organizations." The State Board has upheld the <br /> Regional Board's process for implementing narrative water quality objectives in NPDES permits <br /> (e.g. City of Stockton,UC Davis, City of Woodland). With respect to constituents listed in the <br /> California Toxics Rule or National Toxics Rule, the Regional Board applies the State Board <br /> "Policy for Implementation of Toxics Standards for Inland Surface Waters,Enclosed Bays, and <br /> Estuaries of California(2000)"(SIP) in performing the reasonable potential analysis. With <br /> respect to other constituents, the Regional Board applies USEPA guidance"Technical Support <br /> Document for Water Quality-Based Effluent Limitations" (TSD) in performing the reasonable <br /> potential analysis. <br /> In this permit, the Regional Board implemented the numeric water quality objective for iron <br /> listed in Table III-1 of the Basin Plan. The numeric objective for iron in Table III-1 is expressed <br /> as the dissolved concentration. By regulation(40 CFR 122.45(c)),NPDES permit limits must be <br /> expressed as total recoverable metal. Where the objective is expressed as the dissolved <br /> concentration, a chemical translator is applied to make this conversion. The chemical translator <br /> does not modify the water quality objective,but translates the site-specific dissolved form of the <br /> water quality objective to the total recoverable form. A site-specific translator for iron has not <br /> been developed for this discharge, therefore a default translator of 1 was used in the permit to <br /> develop the effluent limitation. The Regional Board may reconsider the effluent limitation for <br /> iron,but it needs more information to do so. If the City submits dissolved data for this <br /> constituent that demonstrates that there is no reasonable potential to exceed the Basin Plan <br /> objective, the permit can be reopened to remove the limitations based on the new information, or <br /> if reasonable potential exists,the discharger can pursue a site-specific translator study so that an <br /> appropriate total iron effluent limitation can be developed. This may provide the relief sought <br /> by the petitioner,but cannot be done based on current information in the record. <br /> The permit does not apply the secondary MCL for iron, but instead uses the more appropriate <br /> numeric objective in the Basin Plan. However, in response to the petition's allegations that it is <br /> inappropriate to use the MCL as a basis for the effluent limitations, it should be explained that <br />