Accumulation of p,p-DDT in marine organisms exposed to DDT and TBT

Abstract

Olive flounder [Paralichthyls olivaceus], bivalve [Gomphina(Macridiscus) veneriformis melanaegis] and gastropod [Thais chlavigera] were exposed to DDT with (or without) TBT for evaluating the effect of mixed-chemical exposure for DDT accumulation. All target species showed apparent increase of DDT compounds according to exposure period and simultaneously its degradation products (DDD, DDE, DDMU, DBP) also increased. Among the metabolites, DDD contributed to the largest portion with 43 – 97%, and followed by DDE (1 – 55%), DDMU (0.3 – 2%), and DBP (0.2 – 3.6). Although muscle, serum and bile showed similar patterns between two exposure groups, liver of olive flounder showed the different DDT accumulation pattern between two exposure groups. The metabolization of DDT exceeded its accumulation after 30-exposure day in DDT exposure group (DDT / åDDT = 0.15, at 60-exposure day), while the reduction of metabolic activity was found in liver of olive flounder of DDT + TBT exposure group (DDT / åDDT = 0.83, at 60-exposure day). Similar effect was also observed in gastropod but not in bivalve. The reduction of DDT biodegradation in liver of olive flounder and gastropod provide that TBT suppress induction or activity of cytochrome P450 enzyme involved to DDT detoxication.