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MONITORING AND REPORTING PROGRAM NO. R5-2004-0028 7 <br /> NPDES NO. CA0081558 <br /> CITY OF MANTECA, CITY OF LATHROP AND DUTRA FARMS <br /> WASTEWATER QUALITY CONTROL FACILITY <br /> SAN JOAQUIN COUNTY <br /> THREE SPECIES CHRONIC TOXICITY MONITORING <br /> Chronic toxicity monitoring shall be conducted to determine whether the effluent is contributing toxicity <br /> to the San Joaquin River. The testing shall be conducted as specified in EPA/821-R-02-013,Short-term <br /> Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater <br /> Organisms, Fourth Edition, October 2002, or later amendment with Regional Board staff approval. <br /> Chronic toxicity samples shall be taken at the effluent monitoring location specified in this Monitoring <br /> and Reporting Program. Twenty-four hour composite samples shall be representative of the volume and <br /> quality of the discharge. Adequate sample volumes shall be collected to provide renewal water to <br /> complete the test in the event that the discharge is intermittent. Time of sample collection shall be <br /> recorded. The receiving water control shall be obtained immediately upstream of the discharge from an <br /> area unaffected by the discharge in the receiving waters. The sensitivity of the test organisms to a <br /> reference toxicant shall be determined concurrently with each bioassay and reported with the test results. <br /> Both the reference toxicant and effluent test must meet all test acceptability criteria as specified in the <br /> chronic manual. If the test acceptability criteria are not achieved, then the Discharger must re-sample <br /> and re-test within 14 days. <br /> Chronic toxicity monitoring shall include the following: <br /> Species: Pimephales promelas, Ceriodaphnia dubia, and Selenastrum capricornutum <br /> Frequency: Quarterly <br /> Dilution Series: <br /> Dilutions (%1 Controls <br /> 100 50 25 12.5 6.25 <br /> Receiving Lab <br /> Water Water <br /> %WWTP Effluent 100 50 25 12.5 6.25 0 0 <br /> %Dilution Waterl 0 50 75 87.5 93.75 0 100 <br /> %Receiving Water 0 0 0 0 0 100 0 <br /> Dilution water shall be standard laboratory control water due to intermittent receiving water <br /> toxicity. <br />