180,640 research outputs found
trans‐1,3,3,3‐Tetrafluoropropene [MAK Value Documentation, 2019]
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of trans‐1,3,3,3‐tetrafluoropropene [29118‐24‐9]. As the blood:air partition coefficient of trans‐1,3,3,3‐tetrafluoropropene is < 5, the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c) does not have to be taken into account for the derivation of the MAK value. Even after extrapolation of 6‐hour exposure in the animal experiment to 8‐hour exposure at the workplace, the MAK value for trans‐1,3,3,3‐tetrafluoropropene of 1000 ml/m3 can be retained
Naled [MAK value documentation, 2018]
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the work place (MAK value) and the Pregnancy Risk Group of naled [300‐76‐5].
Naled is a cholinesterase inhibitor. In an 13‐week study in rats at 1 mg/m3 there was a 18% inhibition of the cholinesterase activity in erythrocytes. The calculated lower 95% confidence limit of the benchmark dose (BMDL) for a 30% inhibition, which is regarded as not adverse, was 2 mg/m3. A MAK value of 1 mg/m3 was established for the inhalable fraction. It is now lowered to 0.5 mg/m3 taking into account the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c). Since a systemic effect is the critical effect, Peak Limitation Category II is retained and the default excursion factor of 2 confirmed.
For rats, the NOAEL for developmental toxicity was 8 mg/kg body weight and day. Naled was assigned to Pregnancy Risk Group C because the difference between the MAK value and the NOAEL scaled to a concentration in the workplace air was sufficient. There are no new data on developmental toxicity. This classification is retained since now the difference to the MAK value is twice as high
Triethanolamine [MAK Value Documentation, 2016]
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the work place (MAK value) of triethanolamine [102‐71‐6], considering the endpoints respiratory tract irritation and developmental toxicity.
Critical effect of triethanolamine is respiratory tract irritation (focal larynx inflammation). The previous MAK value of 5 mg/m3 is based on 5‐day and 28‐day aerosol studies in rats with a LOAEC of 20 mg/m3. A benchmark calculation gives a BMDL05 of 14,1 mg/m3. Since 2014, the Commission uses an empirical approach to set MAK values for substances with critical effects on the upper respiratory tract or the eyes. Based on this approach, a concentration of 4,7 mg/m3 for the work place air can be calculated from this BMDL05. Therefore the MAK value of 5 mg/m3 is retained.
As local effects are critical, Peak Limitation Category I is retained. At an excursion factor of 2, the allowable maximum concentration is still below the BMDL05.
NOAEL for fetotoxicity are 300 mg/kg bw and day in rats and 1125 mg/kg body weight and day in mice . Teratogenicity was not tested. Nevertheless, because the calculated margins between NOAEL and MAK value are very high, and alkylamines lack teratogenicity, there is no reason to fear damage to the embryo or foetus when the MAK value is observed. Therefore, triethanolamine is assigned to Pregnancy Risk Group C
trans-1,3,3,3-Tetrafluorpropen [MAK Value Documentation in German language, 2019]
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of trans‐1,3,3,3‐tetrafluoropropene [29118‐24‐9]. As the blood:air partition coefficient of trans‐1,3,3,3‐tetrafluoropropene is < 5, the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c) does not have to be taken into account for the derivation of the MAK value. Even after extrapolation of 6‐hour exposure in the animal experiment to 8‐hour exposure at the workplace, the MAK value for trans‐1,3,3,3‐tetrafluoropropene of 1000 ml/m3 can be retained
2,3,3,3‐Tetrafluoropropene [MAK Value Documentation, 2019]
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of 2,3,3,3‐tetrafluoropropene [754‐12‐1]. As the blood:air partition coefficient of 2,3,3,3‐tetrafluoropropene is < 5, the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c) does not have to be taken into account for the derivation of the MAK value. Moreover, the extrapolation of 6‐hour exposure in the animal experiment to 8‐hour exposure at the workplace does not need to be applied because the effect is much more dependent on the concentration than on time. The MAK value for 2,3,3,3‐tetrafluoropropene of 200 ml/m3 can therefore be retained
trans‐1,3,3,3‐Tetrafluoropropene : MAK Value Documentation, 2019
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of trans‐1,3,3,3‐tetrafluoropropene [29118‐24‐9]. As the blood:air partition coefficient of trans‐1,3,3,3‐tetrafluoropropene is < 5, the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c) does not have to be taken into account for the derivation of the MAK value. Even after extrapolation of 6‐hour exposure in the animal experiment to 8‐hour exposure at the workplace, the MAK value for trans‐1,3,3,3‐tetrafluoropropene of 1000 ml/m3 can be retained
Ethylbenzene : MAK Value Documentation, 2018
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) and the Pregnancy Risk Group of ethylbenzene [100‐41‐4]. Critical effect is the liver toxicity, which is observed as centrilobular hypertrophy and liver weight increase resulting from the induction of enzymes and proliferation of hepatocytes, in long‐term studies with rats and mice. In an oral 13‐week study a NOAEL of 75 mg/kg bodyweight and day for rats and a NOAEC of 75 ml/m3 for liver cell proliferation in mice were established. Based on this data, a MAK value of 20 ml/m3 had been set. This value is now reaffirmed even considering the increased respiratory volume at the workplace for the cell proliferation study (see List of MAK and BAT Values, Sections I b and I c). Since a systemic effect is critical, Peak Limitation Category II is retained and since it is not clear whether the effects are due to the metabolites or ethylbenzene the default factor of 2 is confirmed. The NOAEC for developmental toxicity in rats is 500 ml/m³ and after considering the increased respiratory volume at the workplace the difference to the MAK value is sufficient. Therefore, damage to the embryo or foetus is unlikely when the MAK value is observed and ethylbenzene remains in Pregnancy Risk Group C
N,N ‐Dimethylacetamide [MAK Value Documentation, 2018]
No full textThe German Commission for the investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) and the Pregnancy Risk Group of N,N‐dimethylacetamide [127‐19‐5].
N,N‐Dimethylacetamide causes focal cystic degenerations, peliosis, hemosiderin/lipofuscin accumulation and apoptosis in the liver of rats and male mice after chronic whole body inhalation at 100 ml/m3. The NOAEC in both species is 25 ml/m3. Elastane fibre workers with exposure to N,N‐dimethylacetamide show hepatocellular injury. The data at the workplace is not adequate to derive a MAK value. The former MAK value of 10 ml/m3 was derived from the NOAEC of 25 ml/m3 in rats and mice. The MAK value is now lowered to 5 ml/m3 which takes into account the increased respiratory volume at the workplace because the blood:air partition coefficient of N,N‐dimethylacetamide is > 5 (see List of MAK and BAT Values, Sections I b and I c). Since a systemic effect is critical, Peak Limitation Category II is retained. The default excursion factor of 2 is retained as well, as the mechanism of action and the half‐life in blood are not known.
In rats and rabbits, N,N‐dimethylacetamide induces via inhalation at 450 or 570 ml/m3, respectively, and above, specific teratogenic effects, cardiovascular and skeletal malformations. The NOAEC for teratogenicity in rats and rabbits are 300 or 200 ml/m3, respectively. The lowest NOAEC for developmental toxicity in rats and rabbits are 100 and 57 ml/m3, respectively. Considering the increased respiratory volume at the workplace, the NOAEC for rabbits is only six times the MAK value. However, taking into account that the NOAEC could be higher than 57 ml/m3 and the observed effects, reduced fetal body weight and increased incidence of skeletal variations, are considered marginal, the difference to the MAK value is sufficient. Therefore, damage to the embryo or foetus is unlikely when the MAK value is observed and N,N‐dimethylacetamide remains assigned to Pregnancy Risk Group C. Skin contact should be avoided as N,N‐dimethylacetamide is designated with an “H”
Naled : MAK value documentation, 2018
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the work place (MAK value) and the Pregnancy Risk Group of naled [300‐76‐5]. Naled is a cholinesterase inhibitor. In an 13‐week study in rats at 1 mg/m3 there was a 18% inhibition of the cholinesterase activity in erythrocytes. The calculated lower 95% confidence limit of the benchmark dose (BMDL) for a 30% inhibition, which is regarded as not adverse, was 2 mg/m3. A MAK value of 1 mg/m3 was established for the inhalable fraction. It is now lowered to 0.5 mg/m3 taking into account the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c). Since a systemic effect is the critical effect, Peak Limitation Category II is retained and the default excursion factor of 2 confirmed. For rats, the NOAEL for developmental toxicity was 8 mg/kg body weight and day. Naled was assigned to Pregnancy Risk Group C because the difference between the MAK value and the NOAEL scaled to a concentration in the workplace air was sufficient. There are no new data on developmental toxicity. This classification is retained since now the difference to the MAK value is twice as high
Triethanolamine : MAK Value Documentation, 2016
No full textThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the work place (MAK value) of triethanolamine [102‐71‐6], considering the endpoints respiratory tract irritation and developmental toxicity. Critical effect of triethanolamine is respiratory tract irritation (focal larynx inflammation). The previous MAK value of 5 mg/m3 is based on 5‐day and 28‐day aerosol studies in rats with a LOAEC of 20 mg/m3. A benchmark calculation gives a BMDL05 of 14,1 mg/m3. Since 2014, the Commission uses an empirical approach to set MAK values for substances with critical effects on the upper respiratory tract or the eyes. Based on this approach, a concentration of 4,7 mg/m3 for the work place air can be calculated from this BMDL05. Therefore the MAK value of 5 mg/m3 is retained. As local effects are critical, Peak Limitation Category I is retained. At an excursion factor of 2, the allowable maximum concentration is still below the BMDL05. NOAEL for fetotoxicity are 300 mg/kg bw and day in rats and 1125 mg/kg body weight and day in mice . Teratogenicity was not tested. Nevertheless, because the calculated margins between NOAEL and MAK value are very high, and alkylamines lack teratogenicity, there is no reason to fear damage to the embryo or foetus when the MAK value is observed. Therefore, triethanolamine is assigned to Pregnancy Risk Group C
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