BIOTRANSFORMATION AND TOXICOKINETICS OF TRICHLOROANILINES IN FISH IN RELATION TO THEIR HYDROPHOBICITY

Biotransformation, bioconcentration, uptake and elimination were studied in guppy (Poecilia reticulata) for a series of trichloranilines and a trichlorobenzene. Experimentally determined bioconcentration (BCF) values for trichloroanilines were less than those calculated based on a relation between BCF and K(ow) for chlorobenzenes, and differences between the BCF values of isomers were observed. The uptake rate constants of all chemicals tested were approximately equal. The values of the elimination rate constants of two isomers (2,3,4-trichloroaniline and 3,4,5-trichloroaniline) were higher than calculated values based on a relation between log K(ow) and elimination rate constants for chlorobenzenes. These higher elimination rate constants can be explained by a substantial influence of biotransformation. It was shown that these compounds are N-acetylated by the guppy. In contrast, 2,4,5-trichloroaniline also showed a relatively high elimination rate constant; however, no acetylation product was detected. The elimination rate constants of 1,2,3-trichlorobenzene and 2,4,6-trichloroaniline, the isomer with the highest BCF value, were equal to the calculated elimination rate constants indicating that biotransformation does not influence the elimination of these compounds. Biotransformation products for these compounds were not detected.