SITE INFORMATION AND CORRESPONDENCE 1980-1999

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The ditch running east and west on the south side of the plant empties via a valve into Dredger Cut. That ditch collects tailwater from fields that surround the ditch. DeltaKeeper is informed that that ditch has historically discharged into Dredger Cut during the fall and winter months. This irrigation ditch should be tested for TDS at the first flush since it may discharge water that contains TDS concentrations that exceed water quality standards into Dredger Cut. It is also likely that this ditch contains other pollutants that have been leeched with the irrigation tailwater. The Discharger should be required to conduct priority pollutant testing on the ditch effluent. D. A Defensible Reasonable Potential Analysis And Limit For Bis (2-ethylhexyl)phtahalate Must Be Included In The Permit. Historical monitoring data reveals levels of Bis (2-ethylhexyl)phtahalate of 130µg/1 (1992) and 190 µg/1 (1993). It is inappropriate to discard historical date if proper laboratory quality assessment and quality control measures were followed. No mention is made of whether the QA/QC for the early sampling was reviewed. All subsequent analyses were at detection limits (10 to 15 µg/1) that far exceed criteria. Bis (2-ethylhexyl)phtahalate is a constituent limited by the National Toxics Rule (NTR) which must be included in permits if there is a reasonable potential for the discharge to exceed the standard. The NTR limitation for Bis (2-ethylhexyl)phtahalate is 1.8 µg/1. The Drinking Water Standard for Bis (2-ethylhexyl)phtahalate is 4µg/1. EPA policy is that non-detection is not equivalent to zero. Where monitoring results are reported as non-detect because of inadequate detection limits, a value of half the detection limit has often been used. Using a value of half the detection limit clearly reveals that the discharge has a reasonable potential to exceed a numerical standard. The Tentative Permit should be modified to include an effluent limit for Bis (2-ethylhexyl)phtahalate. II. THE PROPOSED PERMIT FAILS TO COMPLY WITH FEDERAL AND STATE ANTIDEGRADATION POLICY. All effluent limitations must be expressed in terms of mass limits that lock in the highest levels achieved since 1975 to comply with antidegradation policy. Allowing an increase in the mass of pollutants identified as impairing a waterbody listed as impaired pursuant to 303(d) of the Clean Water Act cannot be construed as complying with antidegradation requirements. The Federal Antidegradation Policy at 40 CFR 131.12 states,in part,that before allowing waters of the nation to be degraded the"State shall assure that there shall be achieved the highest statutory and regulatory requirements for all new and existing point sources and all cost-effective and . reasonable best management practices for nonpoint source control. DeltaKeeper,Tentative NPDES Permit,Lodi, 17 December 1999,Page 5.