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Pacific EcoRisk Environmental Consulting & Testing <br /> 2.3 Acute Toxicity Testing with Fathead Minnows <br /> The fathead minnows used in this test were obtained from a commercial supplier(Thomas Fish <br /> Company,Anderson,CA).These fish were maintained at 20°C in aerated aquaria containing <br /> EPA synthetic soft water prior to their use in this test. <br /> This hazardous waste evaluation was run at sample concentrations of 250,500, and 750 mg/L, <br /> with a Lab Control consisting of the same synthetic EPA "soft" water.There were 2 replicates at <br /> each test treatment,each replicate consisting of 9.2 L of media in a 10-L container.Water quality <br /> characteristics (pH and dissolved oxygen [D.O.]) were determined for the test solution in each <br /> test replicate prior to initiation of this test. <br /> The test was initiated with the random allocation of 10 juvenile fathead minnows into each <br /> replicate container. These containers were placed in a temperature-controlled room at 20°C, <br /> under fluorescent lighting on a 16L:8D photoperiod. <br /> Each day,each replicate container was examined,and the number of live fish in each was <br /> recorded.Routine water quality characteristics (temperature,pH,and D.O.) of the treatment <br /> waters were measured and recorded for each replicate container each day. <br /> After 96 (±2) hrs,the test was terminated and the number of live fish in each replicate container <br /> was determined.The fish in a randomly selected Lab Control treatment replicate were then <br /> euthanized and measured for total length(to the nearest 0.1 mm) and weighed (to the nearest <br /> 0.001 g).The resulting survival data for the waste treatments were evaluated to determine the <br /> LC50 using the CETIS®statistical software (TidePool Scientific,McKinleyville,CA). <br /> Page 2 L j� <br /> 5/19 <br />