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SIMULATING IRRIGATION WATER TOXICITY 53 TABLE II. Quality control and quality assurance measures for the analysis of water (J1g/U and fish (J1g/g) Inorganic and matrix Copper Selenium Zinc Species and measure Water Fish Water Fish Water Fish Razorback sucker LOO" 0.8 0.1 2.9 0.03 0.9 9.5 BECb < < < < < < RSOc (%) 3.6 5.2 4.5 5.8 4.8 5.1 Digestion spiked (%) NSf g 116 104 NS 102 Spiked samplee (%) 102 103 104 89 103 87 Bonytail LOO 1.2 0.3 3.2 0.03 0.8 8.4 BEC < < < < < < RSO (%) 3.6 7.5 4.6 5.0 4.0 2.6 Digestion spike (%) NS 90 106 NS 107 Spiked sample (%) 102 99 91 95 101 104 a LOD: limit of detection. b BEC: background equivalent concentration: < less than LOD; > greater than LOD. e RSD: relative standard deviation for triplicate sample preparation and analysis. d Digestion spike: percent recovery of element spiked in a sample prior to digestion. e Spiked sample: percent recovery of element spiked in a sample after digestion and prior to analysis. f NS: water samples analyzed for copper and zinc were measured directly with graphite furnace and did not incorporate digestion of samples. g Concentration of prepared digestion spike too low for measurement. were within the recommended range. Except where noted, residue concentrations in tissues and diet were expressed on a dry weight basis. Statistical Analysis Toxicant effects on percent survival (arcsine-trans- formed values), growth, whole-body concentrations of copper, selenium, and zinc (logarithmically transformed values), fish behavioral activity (square root trans- formed), and swimming performance of fish in expo- sure treatments and controls were compared by one-way analysis of variance. Treatment means were compared by the Bonferroni (Dunn) multiple-means comparison test (Snedecor and Cochran, 1967). In statistical analy- ses, individual growth chambers or replicate aquaria were the experimental unit because biological mea- surements were made on different fish within replicate growth chambers or aquaria. RESULTS Eggs of razorback sucker contained 2.8 p,g/g selenium (assuming 75% moisture; analyzed as 0.69 p,g/g wet weight), whereas bonytail eggs contained 2.2 p,g/g (assuming 75% moisture; analyzed as 0.56 p,g/g wet weight). The commercial fish food, Biodiet, used in the two studies contained 11-28 p,g/ g copper, 1.7-2.0 p,g/g selenium, and 93-169 p,g/g zinc. Brine shrimp contained 2.7 p,g/g selenium. Dissolved oxygen con- centrations in the razorback sucker study averaged 6.5 mg/L and in the bonytail study averaged 6.4 mg/L. Concentrations of copper, selenium, and zinc in expo- sure water were close to nominal concentrations (Table III). Survival of razorback sucker larvae was reduced after 60 and 90 days of exposure in the 8X and 16X treatments (Table IV). In bony tail, survival was re- duced only in the 16X treatment, but it occurred ear- lier than with razorback sucker at 30 days of exposure. Growth, measured as total length and weight, of razorback sucker was reduced in a concentration-re- sponse manner as early as 30 days of exposure in the 2X-16X treatments, but after 90 days of exposure reduced growth was observed in the 4X and higher treatments (Table V). Condition factor was reduced in the IX (environmental concentration) treatment at 30 and 60 days of exposure, but persisted only in the 4X and 8X treatments at 90 days of exposure. Reductions in growth at 90 days of exposure were largest for weight; weight of fish in the 4X treatment was reduced by 34% and in the 8X treatment by 92% compared to fish in the control treatment, whereas total length of fish in the 4X treatment was reduced by 13% and in the 8X treatment by 51 % compared to control fish.