Uptake, metabolism, and elimination of14c‐labeled 1,2,4‐trichlorobenzene in rainbow trout and carp

Abstract

Fingerling rainbow trout (S. gairdneri) were exposed to 14C-labeled 1,2,4-trichlorobenzene (TCB) for 8 h in a static exposure (0.018 mg/l) or for 35 days in a continuous-flow exposure (0.020 mg/l) followed by a subsequent elimination period. For the 2 days after the 8 h exposure, the half-time (t1/2) of elimination of 14C from muscle and liver was 0.4 days, while after the 35 day exposure an early rapid elimination of 14C from these tissues (t1/2 = 0.4 days) was followed by a slower elimination (t1/2 = 50 days) during days 4-36. The maximum bioconcentration factors for 14C in muscle and liver were 51 and 102 after the 8 h exposure and 89 and 389 during the 35 day exposure. The values for bile were much greater, reaching 240 after the 8 h exposure and 1400 during the 35 day exposure. When larger trout and carp (C. carpio) were exposed to [14C]TCB (0.2-0.4 mg/l) the bioconcentration factor for bile 14C to water 14C was less than 100. Pretreatment of trout with .beta.-naphthoflavone, an inducer of hepatic mixed-function oxidase, increased this bioconcentration factor for bile to several hundred. Solvent partitioning and TLC indicated that about 60% of the 14C in bile of control trout or carp was present as highly polar biotrnasformation products, while for induced trout the value was more than 90%. TLC in 2 solvent systems suggested that at least 2 such products were present in bile from control fish and at least 3 in bile from induced fish. About 1/2 of the 14C in bile from induced trout was more polar than the 14C in bile from normal trout.