Effects of biotransformation of pentachloronitrobenzene (PCNB) in Mytilus

Mussels were shown to be capable of rapidly biotransforming PCNB via conjugation to glutathione. As a result, PCNB did not accumulate to levels predicted by the compounds` K{sub ow} in a 35 d flow-through exposure, and would not have been detected through current procedures utilized by Mussel Watch programs. Both total glutathione and oxidized glutathione were monitored to determine if depletion of this important peptide was occurring. An apparent decrease was observed at day 18, however, no significant differences were observed. Although the glutathione conjugate was not detected, it was apparently rapidly modified in several steps, one of which releases the free thiol. As thiols are highly reactive, only small amounts of this metabolite were detected in the tissue and water samples. Mussels readily methylate the thiol to form the thioanisole; a separate experiment indicated that the thioanisole bioaccumulates in the tissue, and is depurated at a much slower rate than the parent compound.