Using kepone to exemplify the importance of natural variability in estimating exposure to toxic chemicals from aquatic environmentsThis article is part of a larger document. View the larger document here.
Kepone, decachlorooctahydro-l, 3, 4-metheno-2H-cyclobuta (cd) pentalen-2-one, is a known mammalian carcinogen. From at least 1967 to 1975 when production stopped, it contaminated the Chesapeake Bay. Action levels for kepone in seafood were established by the U.S. Environmental Protection Agency, and various species of finfish, oysters, Crassostrea virginica, and crabs, Callinectes sapidus, often were found to exceed those levels. Detailed sampling and analyses of biota showed that interspecies variability in concentrations often exceeded an order of magnitude. Further examination of the data showed that much of the variability could be explained by factors such as sex, spawning cycle, and migratory patterns. Estimates of human exposure to kepone-contaminated seafood, and, hence, estimates of risk from consuming it, were quite inaccurate unless natural variability was considered. On the positive side, an understanding of the factors controlling natural variability provided alternative risk-management options to minimize risk by decreasing exposure without totally prohibiting harvest or consumption of the resource.