Application of a fish DNA damage assay as a biological toxicity screening tool for metal plating wastewater

The utility of a fish DNA damage assay as a rapid monitoring tool was investigated. Metal plating wastewater was chosen as a sample because it contains various genotoxic metal species. Fish DNA damage assay results were compared to data generated from the conventional whole effluent toxicity (WET) test procedure. The Microtox(R) assay (Azur Environmental, Carlsbad, CA. USA) using Vibrio fischeri was also employed. Eleven samples from two metal plating companies were collected for this evaluation. For the fish DNA damage assay, 7-d-old fathead minnow larvae, Pimephales promelas, were utilized. They were exposed to a series of dilutions at 20 degrees C for 2 h. Whole effluent toxicity tests conducted in this study included two acute toxicity tests with Daphnia magna and fathead minnows and two chronic toxicity tests with Ceriodaphnia dubia and fathead minnows. The fish DNA damage assay showed good correlations with both the acute and chronic WET test results, especially with those obtained with fathead minnows. The kappa values, an index of agreement between the fish DNA damage assay and WET tests were shown to be acceptable (kappa greater than or equal to 0.55). These findings imply that this novel fish DNA damage assay has use as an expedient toxicity screening procedure since it produces comparable results to those of the acute and chronic fathead minnow toxicity tests.