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Pacific EcoRisk Environmental Consulting and Testing <br />2.3 Acute Toxicity Testing with Fathead Minnows <br />The fathead minnows used in this testing were obtained from a commercial supplier (Thomas <br />Fish Company, Anderson, CA). These fish were maintained in aerated aquaria containing 4 ppt <br />salinity water at 20°C prior to their use in this test. <br />This hazardous waste testing was run at sample concentrations of 250, 400, 500, 600, and 750 <br />mg/L, with a Lab Water Control treatment consisting of the same synthetic EPA soft water. <br />There were two replicates at each test treatment, each replicate consisting of 9.2 L of media in a <br />10-L container. Water quality characteristics (pH and dissolved oxygen [D.0.]) were determined <br />for the test solution in each test replicate prior to initiation of this test. <br />The testing 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.0.) of the treatment <br />waters were measured and recorded for each replicate container each day. <br />After 96 (±2) hours, the test was terminated and the number of live fish in each replicate <br />container was determined. The fish in the Lab Control treatment were euthanized and ten fish <br />were then randomly selected and measured for total length (to the nearest 0.1 mm) and weighed <br />(to the nearest 0.01 g). The resulting survival data were evaluated to determine the LCso using <br />CETIS (TidePool Scientific Software, McKinleyville, CA). <br />Page 2 <br />5/15 q(>