Laserfiche WebLink
pH, and specific conductance were measured weekly; dissolved oxygen was measured daily. <br />Dilution-water characteristics had the following means and ranges: dissolved oxygen, <br />7.5 (7.2-7.9) mg/L; alkalinity, 263 (253-271) mg/L as CaCO3i hardness, 400 (379-411) mg/L as <br />CaCO3; pH, 8.0 (8.0-8.1); specific conductance, 887 (850-910) µS/cm. <br />Alkalinity, hardness, pH, and specific conductance in acute tests were measured at the <br />beginning and end of the exposure period; dissolved oxygen was measured daily; water <br />temperature was measured continuously. A test temperature of 20f1 °C was maintained using a <br />water bath. Dilution-water characteristics during acute tests had the following means and ranges: <br />dissolved oxygen, 6.5 (4.8-7.3) mg/L; alkalinity, 215 (191-231) mg/L as CaCO3; hardness, <br />354 (348-365) mg/L as CaCO3i pH, 8.5 (8.4-8.6); specific conductance, <br />1070 (1050-1120) µS/cm. <br />Characteristics of water used for algae and rotifer culture were: alkalinity, 210 (191-231) <br />mg/L as CaCO3i hardness, 349 (335-365) mg/L as CaCO3; pH, 8.5 (8.4-8.6); specific <br />conductance, 1070 (1050-1120) µS/cm. Concentrations of major cations, anions, and other <br />general water quality characteristics were also determined (Tables Al and A2). <br />Toxicant solutions <br />A selenium stock solution was prepared by dissolving sodium selenate (Na2SeO4i Sigma <br />Chemical Company, St. Louis, Missouri) in de-ionized water. For the ELS test, concentrations <br />were prepared by delivering the stock solution to the diluter using a peristaltic pump. In acute <br />tests, exposure concentrations were prepared by pipetting the desired amount of a selenium stock <br />8 <br />