Hexachlorobenzene: an ecotoxicological profile of an organochlorine compound.

Most data on hexachlorobenzene (HCB) in the environment concern its occurrence in the aquatic environment, i.e., in marine and fresh-water ecosystems in which the HCB build-up and increased concentrations in sediments and food-chain organisms are well documented. Food-chain bioaccumulation is also known in terrestrial ecosystems, but data on atmospheric contamination seem scarce and unreliable. However, it is likely that HCB is transported by the atmosphere in low concentrations which are sufficient to make significant contributions to the global distribution of HCB. HCB is of low or moderate acute toxicity, and is not an immediate or acute cause for concern. Nevertheless, it should be classified as a hazard to the environment due to its persistence and its high rate of bioaccumulation.