Hexachlorobenzene in the marine environment: distribution, fate and ecotoxicological aspects.

The distribution of hexachlorobenzene (HCB) among different matrices of the marine environment has been determined. Low HCB concentrations in water (less than 0.1 ng/l) are reflected in sediments and in biota. Laboratory experiments can predict HCB levels in mussels but underestimate those for fish, suggesting distribution mechanisms such as food-chain relationships and metabolic capabilities which usually cannot be predicted from bioassays. Concentrations of HCB in sea water are so low that no toxic effects can be observed in marine biota, but in fish livers HCB may reach levels higher than those considered safe for human consumption. In the edible parts of fish generally, the levels are too low to render sea-food unusable for man. In bioconcentration experiments a lipid-related bioconcentration factor (BCF) of 3 X 10(5) was determined and several metabolites were formed, one of which was identified as methylthio-pentachlorobenzene.