| OCR Text |
Show PMX-I061 Page 7 of 13 The algal media will be 1 /lm filtered water collected from Great Salt Lake. Each replicate will be inoculated with a concentrated D. viridis stock solution to give a cell density of Ixl O" cells/ml., A final check of cell density will be made in three of the test solutions within two hours of inoculation. Every 24 hours until test termination (96 hours), four replicates from each test concentration and the control will be randomly selected for measuring cell density. This data is necessary to most accurately quantitate specific growth inhibition and area under the growth curve. Cell density measurements will be made using spectrophotometer. By the end of the 96 hour testing period, controls must reach a cell density of at least 2.0 105 cells/nil, and there must be less than 20% variation in cell density among the control replicates or the test will be considered unacceptable. x A summary of test conditions is presented in Table 1. 4.5 Water Quality Measurements The following water quality conditions will be recorded/maintained during the tests: • Salinity and pH. These parameters will be measured at test initiation and termination in the high, medium and low selenate concentrations and the control. • Water Water temperature of the test solutions will be maintained at 25 + 1 0 C in an environmental growth chamber. Air will be measured and 24 recorded hours. temperature every Temperature. In addition, characteristics of the test solutions will be observed and recorded, (e.g. precipitated materials, cloudiness, etc). 4.6 Analytical Chemistry The purpose of the analytical chemistry will be to confirm selenate concentrations present in test and control chambers. These samples will be collected from each test concentration initiation and termination of the test. Samples will be analyzed for total selenate. Selenate concentrations will be measured using ICP-MS (EPA Method 6010) by a laboratory that has demonstrated to achieve detection limit, precision, and accuracy the. ability at requirements. 4.7 Data Analysis Test concentrations used for statistical analysis, will be based on the geometric mean of analytically verified concentrations taken at test initiation and termination; |
