Abstract |
Test fish were obtained from Windmill Fish Hatchery, Kernersville. N.C. After holding for at least 7 days in the hatchery, the fish were brought to the laboratory where groups of 10 fish were transferred to 10 gallon glass test aquaria for the full scale tests. Each aquarium was lined, when appropriate, with a polyethylene bag and contained slightly less than 36 liters of hatchery well water, brought from the hatchery along with the fish. Prior to testing, the fish were held in the test aquarium for three days without feeding. During this period the water was continuously aerated and the fish were closely observed to ensure that they were in good health and did not show any signs of unusual stress. The range of concentrations used for the full scale costs was determined by performing preliminary 96 hour studies at concentrations of 1, 10, 100 and 1000 mg/1 of the test material. Four-liter beakers, each containing 3-4 fish were used for these range-finders. Test concentrations chosen for the full-scale test were between the highest concentration in the range-finder which gave no mortalities and the lowest concentration which gave 1007.mortality. In all, five concentrations equally spaced on a logarithmic scale were tested. |