Laserfiche WebLink
Client: Copper Mountain CMD CO-0021598 SCG Project No.: 310921 <br />Site: WWTP <br />Test Procedures <br />Upon receipt at the lab, samples are analyzed for alkalinity, hardness, conductivity, <br />dissolved oxygen, ammonia, chlorine and pH. Alkalinity and hardness are determined <br />titrimetrically according to methods described in Hach Chemical Company'. Ammonia is <br />measured by a Thermo Orion ion-selective electrode according to the procedures in <br />APHA/AWWA/WEF2. Conductivity, dissolved oxygen and pH probes were used to take these <br />measurements. <br />The test followed procedures in EPA' and CDPHE' guidelines. Exposure concentrations <br />included control (0%), 12.5%, 25%, 50%, 75% and 100% mixtures, diluted with moderately hard <br />laboratory reconstituted water. <br />Individual Ceriodaphnia dubia were placed in 30ml plastic containers containing <br />approximately 15ml of exposure medium. Ten replicates at each concentration were used. The <br />animals were fed daily with the YCT mixture and an equal volume of the green algae <br />(Selenastrum capricornutum). The exposure medium was changed daily in each container and <br />the number of young released overnight were counted and recorded. Young were removed from <br />the containers daily and discarded. Routine measurements were made each day of temperature, <br />dissolved oxygen and pH before and after the water changes. <br />Fathead minnow were exposed in 504ml plastic cups to which 250ml of media was added <br />and replaced daily. Four replicates were used at each concentration. Ten fish, less than 24-hours <br />old, were placed in each cup. The fish were monitored daily for survival and fed live Brine <br />shrimp at least twice per day. After seven days, the fish were removed from the cups, <br />euthanized, and then placed in aluminum pans and dried in an oven for a minimum of six hours <br />at 100°C. The pans were then weighed on a five-place analytical balance to determine the <br />average dry weight of the fish from each replicate. <br />Data Analysis <br />Data from the test(s) were analyzed on a personal computer using the TOXCALC <br />package developed by Tidepool Scientific Software. Statistical tests used in the analyses are <br />shown in Table 1. Test acceptability was determined using control survival and performance <br />criteria, concentration-response relationships and percent minimum significant differences <br />(USEPA "). <br />SeaCrest Group 6