Uptake of chloro- and bromobiphenyls, hexachloro- and hexabromobenzene by fish

Conclusions

No major differences between the accumulation of di- and tetra-, bromo- and chlorobiphenyls by fish are apparent. In contrast to hexachlorobenzene, hexabromobenzene is not accumulated either from water or from food.

The concentration of both chloro- and bromo-substituted compounds in water was of the same order of magnitude, and in both cases fish accumulated higher concentrations from water than from food. In both groups of compounds, the accumulation coefficients generally decreased with increasing degree of substitution during the uptake from water, and increased with increasing degree of substitution when taken up from food. Of the dihalobiphenyls, the 3,4-isomer accumulated from water much less than 2,6- and 2,4-dihalobiphenyl, and did not accumulate from food.

Partially debrominated compounds were not detectable in fish exposed either from water or from food, but a dibromobiphenylol was tentatively detected in the former. Mortality after exposure to chlorine occurred among fish fed the mixture of brominated hydrocarbons and their toxicity should be further studied.