1,4-Dichlorobenzene. Documentation of proposed values of occupational exposure limits (OELs)

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1,4-Dichlorobenzene. Documentation of proposed values of occupational exposure limits (OELs)

Journal Title: Podstawy i Metody Oceny Środowiska Pracy - Year 2015, Vol 31, Issue 4

Abstract

1,4-Dichlorobenzene is a solid crystallinesubstance, colorless or white, with camphorlikeodour. It sublimes at room temperature. Itis used as insecticide (mainly in the mothballs),as a fumigant and as a component of indoordeodorants and air-fresheners used in dumpsters.1,4-Dichlorobenzene is used in the synthesis ofpolyphenylene sulfi de, 1,2,4-trichlorobenzene,2,5-dichloroaniline and dyes. It is also used inpharmaceutical industry.1,4-Dichlorobenzene is absorbed into the bodymainly by inhalation. It has low acute toxicity.Chronic effects in humans include irritation to eyesand mucous membranes of the upper respiratorytract, impaired lung function parameters, impairedkidney and liver function.In prolonged and chronic animal studies changeswere observed mainly in a liver. In male ratschanges were also observed in kidneys. Afterchronic exposure to 1,4-dichlorobenzene, changesdue to irritation were observed in epithelium of thenasal cavity.1,4-Dichlorobenzene has no signifi cant genotoxicpotential. Most in vitro and in vivo mutagenicitystudies were negative.1,4-Dichlorobenzene was carcinogenic to animals.Liver tumors were observed in the male and femalemice after oral administration of 1,4-dichlorobenzeneand after inhalation. The mechanism of liver tumorin mice after administration of 1,4-dichlorobenzeneby ingestion or inhalation is not exactly clearbut studies indicate the threshold nature of thiseffect. Adenocarcinomas of the renal tubule wereobserved in male rats after oral administration of1,4-dichlorobenzene. Specifi c genotoxic mechanism,irrelevant for humans, is responsible for kidneytumors in male rats exposed to 1,4-dichlorobenzene.1,4-Dichlorobenzene is not embryotoxic, teratogenicor fetotoxic. There was no impact on reproductivefunctions of animals in the two-generation study inrats exposed to 1,4-dichlorobenzene by ingestion orby inhalation.A critical effect for exposure to 1,4-dichlorobenzeneis hepatotoxic activity. Oral administration of1,4-dichlorobenzene (in capsules) in dogs for 52weeks caused changes in liver and NOAEL valueobtained from this study was 10 mg/kg/day.On the basis of this NOAEL value, after taking intoaccount uncertainty factors, the MAC (TWA) valueof 12 mg/m3 and STEL of 36 mg/m3 (3 times NDS)were recommended.There is no quantitative experimental data on skinabsorption of 1,4-dichlorobenzene, but on the basisof modeling data the “Skin” notation was addedbecause absorption of substances through the skincan be as important as inhalation. It is recommendedto label the substance with symbol “I” (irritant).

Authors and Affiliations

KATARZYNA KONIECZKO, SŁAWOMIR CZERCZAK

Keywords

1 4-dichlorobenzen narażenie zawodowe NDS 1 4-dichlorobenzene Occupational Exposure OEL

EP ID EP81609
DOI -
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