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The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated cresol (all isomers) [1319-77-3] and evaluated a maximum workplace concentration (MAK value) of 1 ml cresol/m3. Only one... more
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated cresol (all isomers) [1319-77-3] and evaluated a maximum workplace concentration (MAK value) of 1 ml cresol/m3. Only one study has been published in which the relationship between external exposure to cresol and cresol excretion in urine was investigated. However, the time-weighted average of external exposure in this study was far below the current MAK value. Data on the relationship between internal exposure and effects are not available. As appropriate data for deriving the critical internal dose for cresol are lacking, a biological tolerance value (BAT value) for this compound cannot be established and the biological guidance value (BLW) was withdrawn.
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Research Interests: Materials Science, Metallurgy, Environmental Monitoring, Filtration, Medicine, and 15 moreManganese, Aerosols, Germany, Humans, Risk factors, Middle Aged, Adult, Particle Size, Occupational Exposure, Public health systems and services research, Particulate Matter, Risk Factors, Cross Sectional Studies, limit of detection, and Respiratory Protective Devices
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The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated 1,2-dimethylhydrazine [540-73-8] considering all toxicological end points. Chronic and subchronic exposure induced... more
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated 1,2-dimethylhydrazine [540-73-8] considering all toxicological end points. Chronic and subchronic exposure induced adverse effects on the liver, heart and kidneys of mice and the liver and bile ducts of mini-pigs and guinea pigs. In dogs, 1,2-dimethylhydrazine caused adverse effects on the liver. The critical effect of 1,2-dimethylhydrazine is its carcinogenic potential. In carcinogenicity studies, 1,2-dimethylhydrazine induced various intestinal and vascular tumours such as haemangiosarcomas in addition to lung tumours in rodents after oral and intraperitoneal application. Particularly noteworthy is the high incidence of colon carcinoma in rats, which was observed both after acute and chronic application. Additionally, tumours of the digestive system were observed in hamsters and monkeys after subcutaneous or intramuscular injection. On the basis of the carcinogenic...
The 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 1,1,1-trichloroethane [71-55-6].... more
The 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 1,1,1-trichloroethane [71-55-6]. Critical are pre-narcotic effects observed in male volunteers exposed at rest to 350 ml/m3. The MAK value has now been lowered to 100 ml/m3 taking into account the increased respiratory volume at the workplace because the blood:air partition coefficient of 1,1,1-trichlorethane is > 5 (see List of MAK and BAT Values, Sections I b and I c). As a systemic effect is critical, Peak Limitation Category II is retained. To avoid short-term pre-narcotic effects, the excursion factor of 1 is also retained. The differences between the MAK value and the NOAECs for developmental toxicity in rats, rabbits and mice are sufficient even taking into account the increased respiratory volume at the workplace. Therefore, damage to the embryo or foetus is unlikely whe...
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated monomethylhydrazine [60-34-4] considering all toxicological end points. The acute toxicity of monomethylhydrazine is... more
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated monomethylhydrazine [60-34-4] considering all toxicological end points. The acute toxicity of monomethylhydrazine is caused by depletion of gamma-aminobutyric acid leading to the effects on the central nervous system. Chronic and subchronic exposure induces haemolytic effects and adverse effects on the liver. In carcinogenicity studies, inhaled monomethylhydrazine caused tumours of the lungs, liver, blood vessels and olfactory epithelium in female mice and tumours of the nose and adrenal glands in male hamsters. Orally applied, it induced tumours of the lungs and liver in mice and tumours of the colon and small intestine in hamsters. Monomethylhydrazine therefore remains classified in Carcinogen Category 2 and no maximum concentration at the workplace (MAK value) can be derived. Monomethylhydrazine is genotoxic in vitro and in vivo and demonstrates a mutagenic potent...
The 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), the Pregnancy Risk Group, sensitization, absorption through the... more
The 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), the Pregnancy Risk Group, sensitization, absorption through the skin and germ cell mutagenicity of toluene [108-88-3]. The critical effects of toluene are neurotoxicity in humans, especially on the central nervous system, behavioural toxicity and ototoxicity as well as effects on colour vision. No indication of chronic effects in the range of 50 ml toluene/m3 were observed in an epidemiological longitudinal study in rotogravure printing, even taking into account individual estimates of lifetime exposure to toluene. Extensive, well-controlled experimental studies demonstrate no short-term toxic effects on behaviour at exposures lower than 50 ml toluene/m3 (in some cases even higher), which would show up as a significant reduction in performance in neuropsychological tests. Therefore, on the basis of numerous huma...
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated 1,1-dimethylhydrazine [51-14-7] considering all toxicological end points. The acute toxicity of 1,1-dimethylhydrazine is... more
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated 1,1-dimethylhydrazine [51-14-7] considering all toxicological end points. The acute toxicity of 1,1-dimethylhydrazine is caused by depletion of gamma-aminobutyric acid leading to the effects on the central nervous system. During chronic and subchronic exposure, adverse effects on the blood, liver, nervous system, colon and spleen were observed in dogs and adverse effects on the liver and colon were observed in rats. In mice, the substance causes toxicological effects on the nose, lungs and gall bladder. In carcinogenicity studies, inhaled 1,1-dimethylhydrazine caused tumours in the lungs, pituitary gland and pancreas in rats in addition to thyroid carcinomas, haemangiosarcomas and Kupffer cell sarcomas in mice. In carcinogenicity studies using ultra-pure 1,1-dimethylhydrazine, a number of tumours formed in mice, including in the lungs, liver, blood vessels and the na...
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The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated N,N -dimethylformamide [68-12‐2] taking into account the increased respiratory volume at the workplace (see List of MAK... more
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated N,N -dimethylformamide [68-12‐2] taking into account the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c). N,N -Dimethylformamide is a liver toxin and the maximum concentration at the workplace (MAK value) of 5 ml/m3 was set using data from a two-year study in mice showing liver cell hypertrophy and single cell necrosis at the lowest concentration tested of 25 ml/m3. In this study, rats were less susceptible as regards the liver toxicity of N,N -dimethylformamide. Species differences in toxicokinetics are a plausible explanation for the higher toxicity in mice. As human metabolism of N,N -dimethylformamide is quantitatively similar to that of rats, their susceptibility is expected to be similar to that of rats. On the basis of the NOAEC (no observed adverse effect concentration) of 25 ml/m3 for rats, the MAK value o...
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The 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 ethanethiol [75-08-1]. No new studies are available for... more
The 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 ethanethiol [75-08-1]. No new studies are available for ethanethiol itself. Therefore, the MAK value is derived by read-across with the structurally similar methyl mercaptan for which the MAK value of 0.5 ml/m3 is based on slight behavioural changes at 2 ml/m3 in a 90-day inhalation study in rats. The MAK value of 0.5 ml/m3 for ethanethiol is supported by a limited inhalation study with 3 volunteers, showing irritation and other symptoms after repeated exposure to ethanethiol in a concentration of 3.9 ml/m3, but not after 0.39 ml/m3. The behavioural changes in rats exposed to methyl mercaptan are presumably not neurotoxic effects but a result of the odour nuisance or the local irritation. Therefore, ethanethiol is classified in Peak Limitation Category I with an excursion factor of 1 by analogy with methyl me...
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The 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 methanol [67-56-1] of 200 ml/m3, considering all toxicity... more
The 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 methanol [67-56-1] of 200 ml/m3, considering all toxicity endpoints. Available publications and unpublished study reports are described in detail. Uptake of larger amounts of methanol depresses the central nervous system and leads to developmental toxicity as direct effects of methanol followed by metabolic acidosis and ocular toxicity as formate effects. No neurobehavioral effects were observed in subjects exposed 4 hours to 200 ml/m3 at rest leading to a concentration of 6.5 mg methanol/l blood. The steady state concentration of methanol after exposure to 100 ml/m3 with physical activity is calculated to be 6 mg methanol/l blood and is reached after 8 hours. Therefore, taking into account the increased respiratory volume at the workplace (see List of MAK- and BAT Values, Sections I b and I c), the MAK value ...
In vitro lung cell models like air-liquid interface (ALI) and 3D cell cultures have advanced greatly in recent years, being especially valuable for testing advanced materials (e.g., nanomaterials, fibrous substances) when considering... more
In vitro lung cell models like air-liquid interface (ALI) and 3D cell cultures have advanced greatly in recent years, being especially valuable for testing advanced materials (e.g., nanomaterials, fibrous substances) when considering inhalative exposure. Within this study, we established submerged and ALI cell culture models utilizing A549 cells as mono-cultures and co-cultures with differentiated THP-1 (dTHP-1), as well as mono-cultures of dTHP-1. After ALI and submerged exposures towards α-quartz particles (Min-U-Sil5), with depositions ranging from 15 to 60 µg/cm2, comparison was made with respect to their transcriptional cellular responses employing high-throughput RT-qPCR. A significant dose- and time-dependent induction of genes coding for inflammatory proteins, e.g., IL-1A, IL-1B, IL-6, IL-8, and CCL22, as well as genes associated with oxidative stress response such as SOD2, was observed, even more pronounced in co-cultures. Changes in the expression of similar genes were mor...