Evaluates the risks to human health and the environment posed by exposure to monochlorobenzene, dichlorobenzenes, trichlorobenzenes, tetrachlorobenzenes, and pentachlorobenzene. These chemicals are produced in huge quantities for use as intermediates in the synthesis of pesticides and in the production of a wide range of consumer and commercial products. A review of data on sources of environmental exposure notes that release to the environment occurs primarily during manufacture and that incineration of chlorobenzenes may lead to the emission of polychlorinated dibenzo-p-dioxins and dibenzofurans. Sections concerned with sources and levels of human exposure conclude that the general population is exposed to the lower chlorinated congeners mainly through inhalation, whereas a greater proportion of the total daily intake of the higher chlorinated compounds is ingested in food; breast-fed babies may receive a higher dose than members of the adult population. Particular concern centres on risks of human exposure arising from the ingestion of contaminated fish and from contaminated indoor air linked to use of these compounds as moth repellents and air fresheners. Because of weaknesses in available studies, the report was unable to predict the environmental impact of low-level contamination with chlorobenzenes, or to identify the mechanisms by which these compounds might enter the food chain. While ambient concentrations are expected to reach toxic levels only in the case of accidental spills or uncontrolled industrial discharge, the report notes the need to avoid discharge of chlorobenzenes into the aquatic environment, as this can result in the build up of persistent residues in sediment or ground water. The most extensive section reviews the large number of experimental studies that have evaluated short-term and long-term effects of exposure to these chemicals, including their carcinogenic, teratogenic, and mutagenic potential. Concerning risks to human health, findings from case reports in occupationally exposed populations point to transient effects on the central nervous system, and irritation of the eyes and upper respiratory tract as the principal health effects of exposure.

eng with summaries in fre spa.

jpn.

WHODOC

WHO monograph

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