Fate of Kepone and Mirex in a Model Aquatic Environment: Sediment, Fish, and Diet

Abstract

Laboratory studies of freshwater sediment and a daphnid–bluegill (Daphnia magna–Lepomis macrochirus) food chain indicated that the organochlorine insecticides Kepone and mirex resist microbial degradation, accumulate and resist metabolism in fish, and move through a food chain. We found no direct evidence of degradation of either compound after 56 d of incubation in freshwater sediments under aerobic or anaerobic conditions. Furthermore, we found no metabolism or co-metabolism of 14C-labeled Kepone in sediments that had long-term preexposure to Kepone and by-products nor did we detect a selective process occurring in the sediments that changed the capacity of the autochthonous microbiota to metabolize Kepone. After 28 d of exposure to 14C-labeled Kepone or mirex in water and natural food, bluegills accumulated Kepone and mirex equal to 10 606 and 12 274 times the respective exposure concentrations. Elimination patterns were dissimilar: mirex tended to persist in fish tissue but Kepone did not. Neither Kepone nor mirex was metabolized by bluegills. Retention of mirex introduced into bluegills by daphnids was about 3 times greater than that of Kepone. Accumulation of Kepone and mirex by bluegills was about half that of DDT.Key words: Kepone, mirex, degradation, freshwater sediment, accumulation, elimination, bluegills, daphnids, residue dynamics, food chain, accumulation index

Fate of Kepone and mirex in the aquatic environment

“…Aerobic and anaerobic hydrosoils from a small man-made reservoir (Little Dixie, Columbia, MO) and from a tributary of the James River in Virginia (Bailey Creek) contaminated with Kepone were exposed to a single application of [14C] Kepone and [14C]mirex. Details of hydrosoil collection, preparation, and exposure to Kepone and mirex were described by Skaar et al (1981). Sample extracts were purified by using carbon/foam column chromatography, as described by Huckins et al (1978), prior to TLC and EC-GC analysis.…”

Bioaccumulation Behavior of Persistent Organic Chemicals with Aquatic Organisms

“…Experiments by Reinert (1972) On dieldrin showed that daphnia and guppies accumulated more from water than from food exposed to similar COncentrations in water. Skaar et al (1981) using bluegills feeding On daphnids found that they accumulated < 7% of their load of kepone and mirex from food. Canton et al (1975) investigated the chlorella-daphnia-lebistes food chain transfer of HCH and concluded that transfer from water was the most important but food was a significant source.…”