Effect of lipophilic complex formation on the uptake and distribution of Hg2+ and CH3−Hg+ in brown trouts (Salmo trutta): Studies with some compounds containing sulphur ligands.

Abstract

Brown trouts, Salmo trutta, were exposed via aquarial water to 203Hg2+ or to CH3 −203Hg+ alone or together with one of the following S-containing substances: sodium dimethyldithiocarbamate (SMC), sodium diethyldithiocarbamate (SEC), potassium ethylxanthate (PEX), sodium isopropylxanthate (SIX), sodium diethyldithiophospbate (SEP), sodium diisopropyldithiophosphate (SIP) or sodium pyridinethione (SPyr). The distribution of the 203Hg2+ and the CH3−203Hg+ in the fishes were then studied by whole-body autoradiography and gamma spectrometry. The results showed that the examined complexing substances can induce increased uptake of both 203Hg2+ and CH3−203Hg+ by the fishes: for 203Hg2+ most of the complexing substances induced a similar increase in various tissues; for CH3−203Hg+ marked variations were seen for different substances. Determinations of chloroform/water partition coefficients showed that the examined substances are able to form lipophilic complexes both with Hg2+ and CH3−Hg+. A facilitated penetration of the lipophilic complexes over the membranes of the gills and other tissues may underly the increments of the tissue-levels of the Hg. It is possible that increased uptake of Hg2+ and CH3−Hg+ induced by complexing substances of this type may have toxicological implications for fishes and for other aquatic organisms.