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DocuSign Envelope ID: D07924E6-3D94-4398-A066-B683COBAB33E <br /> 1 .0 Test Summary <br /> 1.1 Test Conditions/Background <br /> Enclosed are the results of the chronic Ceriodaphnia dubia and Pimephales promelas tests <br /> performed November 5 to 12, 2020 (Round 1), November 17 to 25, 2020 (Round 2) and <br /> January 19 to 27, 2021 (Round 3). The noncompliance chronic toxicity test procedures <br /> followed the methods in EPA documentation (EPA 2002) where applicable. <br /> Results summarized in this report include three rounds of testing. For the first round of testing, <br /> two sets of bench scale treated composite samples were collected on November 4, 2020, <br /> where one set was treated with 0.5 g ethanol/g sulfate (SO4) and the second set was treated <br /> with 1 g ethanol/g SO4. For the second round of testing, a third set of treated composite <br /> samples were collected on November 17, 2020 and treated with 0.25 g ethanol/g SO4. For the <br /> third round of testing, two sets of bench scale treated composite samples were collected on <br /> January 18, 2021, where one set was treated with 0.5 g ethanol/g sulfate (SO4) with lime pre- <br /> softening and the second set was treated with 0.5 g ethanol/g sulfate (SO4) without lime pre- <br /> softening. <br /> For the first two rounds of testing, chronic C. dubia tests were initiated with a full dilution series <br /> (0%, 20%, 40% 60% 80% and 100% treated effluent) using moderately hard reconstituted <br /> (MH recon) water as the dilution water. The P. promelas tests and third round of C. dubia <br /> testing were initiated without dilution, using 0% (MH recon) and 100% treated effluent <br /> concentrations for pass/fail determination. <br /> The dissolved oxygen (D.O.) in the P. promelas tests for 0.5 g ethanol/g SO4, 1.0 g <br /> ethanol/g SO4, 0.25 g ethanol/g SO4,and 0.5 g ethanol/g sulfate (SO4)with lime pre-softening <br /> dropped below 4.0 mg/L on days one, three, six, and four of the test, respectively. All test <br /> solutions were aerated for the duration of the test. The D.O. also dropped below 4.0 mg/L in <br /> the C. dubia test on day 4 of the 0.5 g ethanol/g SO4 test, however, aeration is not approved <br /> for the C. dubia species. While the C. dubia species is less impacted by low D.O., it may have <br /> contributed to the noted toxicity. <br /> Due to a poor hatch of Artemia nauplii, the P. promelas organisms could not be fed in the <br /> afternoon on day 4 of the 0.25 g ethanol/g SO4 test; they were only fed in the morning on this <br /> day. However, because this was such a slight deviation from protocol, we believe that this had <br /> no effect on the outcome of the test. <br /> Daily temperatures were taken in the test chambers for the duration of all tests. The <br /> temperature differed by 3.2°C in the 1 g ethanol/g SO4 C. dubia test and the temperature <br /> differed by 3.9°C in the 0.5 g and 1.0 g ethanol/g SO4 P. promelas tests. <br /> GEI Consultants,Inc. 1 February 2021 <br /> Ecological Division Whole Effluent Toxicity Test Report <br /> Stantec-Elk Ridge Mining and Reclamation,LLC <br />