Uptake and Retention of Mirex by Fish Maintained on Formulated and Natural Diets in Lake Ontario Waters

Abstract

Abstract Fish with no detectable levels of the contaminant mirex were grown in Lake Ontario waters under conditions simulating commercial aquaculture. Benthic black bullheads (Ameiurus melas) were grown in cages placed in a bay of the lake. Pelagic rainbow trout (Oncorhynchus mykiss) were grown in terrestrial raceways served with Lake Ontario waters. Contaminant-free fingerlings were reared to a large size on a commercial ration in these systems, which partially isolated them from the contaminant-laden food web and bottom sediments. Black bullheads fed a mirex-spiked, commercially prepared food had mirex concentrations that exceeded the U.S. Food and Drug Administration (FDA) action level of 0.1 μg/g, significantly higher than concentrations in fish receiving the same commercial food without mirex. Ninety percent of fish receiving the unspiked ration had nondetectable levels of mirex (values below 0.002 μg/g). The 10% containing mirex had concentrations 94% below FDA action level. In the rainbow trout stu...