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N10MTOFIN-G .;k_ND REPORTING F 1ROGiZ.A 2\11 <br />CITY OF STOCKTON <br />AUSTIN ROAD LANDFILL GROUNIDV'ATER TREATiv1ENT SYSTEIN1 <br />SAN JOAQUIN COUNTY <br />THREE SPECIES CHRONIC TOXICITY MONITORING <br />-2- <br />Effluent toxicity monitoring shall be conducted to determine whether the effluent -is likely to <br />contribute toxicity to Littlejohn Creek. The monitoring shall be conducted as specified in the <br />EPA 600/4-91-002. Effluent toxicity samples shall be collected at the discharge from a manhole <br />prior to be discharged into Littlejohn Creek. Grab samples shall be representative of the volume <br />and quality of the discharge. Time of collection of samples shall be recorded. The effluent tests <br />must be conducted with concurrent reference; toxicity tests. Monthly laboratory reference <br />toxicity tests may be substituted upon approval. Both the reference toxicant and effluent test <br />must meet all test acceptability criteria as specified in the EPA manual. If the test acceptability <br />criteria are not achieved, then the Discharger must re -sample and re -test within 14 days. Chronic <br />toxicity monitoring shall include the following: <br />Species: Pime hn ales promelas, Ceriodaphnia dubia, and Selenastrum <br />capricomutum <br />Frequency: <br />Quarterly <br />Dilution Series: <br />The Discharger shall conduct the chronic toxicity testing using <br />100% effluent and two controls. If toxicity is found in any of <br />the 100% effluent tests, the Discharger must immediately retest <br />using the full sampling protocol of 5 dilutions and 2 controls <br />listed below. Toxicity is defined as a statistically significant <br />difference between the 100% effluent sample and either of the <br />controls. Appropriate statistics are defined in EPA 600/4-91- <br />002. <br />Dilutions (%) Controls <br />Receiving Lab <br />100 a 5-Q 25- Ild Water Water - <br />% GWIT Effluent <br />100 75 50 25 12.5 0 0 <br />% Dilution Water' <br />0 25 50 75 87.5. 100 0 <br />% Lab Water <br />0 0 0 0 0 0 100 <br />1 Dilution water shall be receiving water from Littlejohn Creek taken upstream from the <br />discharge point" The dilution series may be altered upon'approval of Regional Board staff. <br />2 Lab water shall meet EPA protocol requirements. <br />CS 005427 <br />City of Stockton 190855-0006 <br />