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1000
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Abstract/Summary
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The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated tetrahydronaphthalene to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available unpublished study reports and publications are described in detail. In animal studies, the target organs of the toxicity of tetrahydronaphthalene are the liver and kidneys and, after inhalation, also the respiratory tract. The relative kidney weights of female rats were increased at tetrahydronaphthalene concentrations of 15 ml/m3 and above in both a 14‐week study and a 14‐day study. The NOAEC was 7.5 ml/m3 in both studies, and 15 ml/m3 for effects on the olfactory epithelium in the 14‐week study. In mice, NOAEC of 15 and 30 ml/m3 were obtained for female and male animals, respectively, after exposure for 14 weeks. From the NOAEC of 15 ml/m3 for effects in the nose of rats and the NOAEC of 7.5 ml/m3 for increased relative kidney weights in female rats, a MAK value of 2 ml/m3 is derived. Both systemic and local effects lead to the same MAK value and no data for local effects or the half‐life are available for humans. The classification in Peak Limitation Category I is therefore based on the lower default excursion factor of 1 as compared to 2 for Peak Limitation Category II. The NOAEL for developmental toxicity and maternal toxicity in rats was 45 mg/kg body weight and day. The difference between the MAK value and the calculated NAEC for developmental toxicity together with the difference between the MAK value and the calculated LAEC for developmental toxicity is, in view of the low severity of the findings and the simultaneous occurrence of maternal toxicity, sufficiently large. Thus, damage to the embryo or foetus is unlikely when the MAK value is observed and the substance is classified in Pregnancy Risk Group C. Tetrahydronaphthalene is not genotoxic and not carcinogenic in 2‐year inhalation studies in rats and mice. Tetrahydronaphthalene is not a contact sensitizer in guinea pigs and no clear results for sensitization in humans are available. Skin contact is not expected to contribute significantly to systemic toxicity.
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