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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 di(2‐ethylhexyl) phthalate [CAS No. 118‐81‐7] in 2017 and has derived a biological guidance value at the workplace (BLW) for the combined urinary concentration of the four major DEHP metabolites mono(2‐ethylhexyl) phthalate (MEHP), mono(2‐ethyl‐5‐hydroxyhexyl) phthalate (5‐OH‐MEHP), mono(2‐ethyl‐5‐oxohexyl) phthalate (5‐oxo‐MEHP) and mono(2‐ethyl‐5‐carboxypentyl) phthalate (5‐cx‐MEPP). Available publications are described in detail. Human studies are not available for deriving a quantitative relationship between the internal dose and the critical toxic effects of DEHP (tumor promotion in the liver, respiratory effects, reproductive and developmental toxicity). Therefore, the evaluation of the BLW was based on the relationship between DEHP uptake by inhalation at the MAK value and the urinary excretion rates of MEHP, 5‐OH‐MEHP, 5‐oxo‐MEHP and 5‐cx‐MEPP, using a conversion factor that defines this relationship. In accordance with this conversion factor external exposure to DEHP at the MAK value corresponds to a combined urinary concentration of the four metabolites of approx. 4 mg/g creatinine at steady state. As the conversion factor has been derived from oral DEHP uptake and metabolite excretion data of only one male volunteer, the concentration of 4 mg/g creatinine is considered a BLW. Sampling time for long‐term exposure is at the end of the shift after several previous shifts.
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