A REVIEW OF THE RELATIONSHIP BETWEEN ACUTE TOXICITY (LC(50)) OF GAMMA-HEXACHLOROCYCLOHEXANE (GAMMA-HCH, LINDANE) AND TOTAL LIPID-CONTENT OFDIFFERENT FISH SPECIES

This paper provides an explanation for a 40-fold difference in the acu te toxicity (LC(50)) of gamma-hexachlorocyclohexane (gamma-HCH, Lindan e) in 14 different fish species, based on well recognized principles o f toxicokinetics and toxicodynamics in combination with a compilation of data from the literature and some original data. The 48-h median le thal concentration (48-h LC(50)) of gamma-HCH in 14 fish species, belo nging to 6 families, range from 22 to 900 mu g/l. A significant positi ve linear relationship was found between lipid content (% of wet weigh t) and the 48-h LC(50) of gamma-HCH in these fish species, revealing t hat the toxicity of gamma-HCH in various fish species is decreasing wi th increasing total lipid content. If median lethal concentrations are normalized for 1% lipid content, then the range of 48-h LC(50)s is re duced to between 18 and 32 mu g/l. It is concluded that lipids of aqua tic organisms can serve (among other functions) as a protective storag e site against the toxic effects of gamma-HCH and, possibly, of other lipophilic, persistent organic chemicals which are bioconcentrated in body lipids. Therefore, in organisms with higher lipid content, a smal ler fraction of a lipophilic chemical will reach target organs (livers , lung, central and peripheral nerves, etc.) to cause adverse effects. Results suggest that this correlation can be used to extrapolate the acute toxicity (48-h LC(50)) of gamma-HCH to other fish species if the ir lipid content is known. Furthermore, the data generated by extrapol ation of this correlation could be useful in the environmental risk as sessment of freshwater and marine organisms.