Maximum concentration values in the workplace

The German system of Maximale Arbeitsplatzkonzentrationen (MAK, Maximum Concentration Values in the Workplace) and Technische Richtkonzentrationen (TRK, Technical Exposure Limits) [16]. 

MAK maximale Arbeitsplatzkonzentration = maximum concentration value in the workplace... 

Hence, organic solvents should be handled with care. In the USA, the threshold limit values [TL values) are used as a measure of the inhalation toxicity for chronic interaction with solvent vapours [90]. In the Federal Republic of Germany, the maximum concentration values at the workplace [MAK values) are used [91, 92]. Threshold limit values refer to airborne concentrations of substances and represent conditions under which it is believed that workers may be repeatedly exposed daily without adverse effect. They refer to time-weighted average concentrations for a normal 8-hour workday... 

Because pulp bleaching agents are, for the most part, reactive oxidising agents, appropriate precautions must be taken in their handling and use. For example, it is important to ensure that the threshold limit values (TLV) (20) in Table 2 are not exceeded in the workplace air. These are airborne concentrations in either parts per million by volume under standard ambient conditions or mg per cubic meter of air. They "represent conditions under which it is beUeved that nearly all workers may be repeatedly exposed, day after day, without adverse effect" (20). TWA refers to a time-weighted average for an 8-h workday STEL is a short-term exposure limit or maximum allowable concentration to which workers can be continuously exposed for 15 minutes. 

EPA has established that hydrogen sulfide is a regulated toxic substance and is a hazardous substance as defined under the Federal Water Pollution Control Act. OSH A has established an acceptable ceiling concentration of 20 parts per million (ppm) for hydrogen sulfide in the workplace, with a maximum level of 50 ppm allowed for 10 minutes maximum duration if no other measurable exposure occurs. NIOSH has set a maximum Recommended Exposure Limit (REL) ceiling value (10 minutes) of 10 ppm. A complete listing of federal and state regulations and recommendations are found in Chapter 7. 

The toxic dose levels of silver and silver compounds have been determined in animal toxicity studies (Sweet 1989). In mice, orally administered silver nitrate had an LD50 of 50 mg kg (the LD50 is the dose required to kill 50% of the test group), whilst silver sulfadiazene had an LD50 of 5000 mg kg. In occupational medicine, the MAK-value (maximum allowable concentration at the workplace) has been set at 0.1 mg m for metallic silver and 0.01 mg m for silver salts as Ag (DFG 2002). The same values were set as TLV (Threshold Limit Values) in the USA (ACGIH 2002). 

MAK (2002) List of MAK and BAT Values. Maximum Concentrations and Biological Tolerance Values at the Workplace. Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Report No. 38, DEG. Wiley-VCH, Weinheim-New York. 

TLV Threshold Limit Value, which is the maximum safe concentration in air in the workplace, expressed as the time-weighted average (TWA) in parts per million by volume, over an 8-hr workday and 40-hr workweek. 

In addition, the Senate commission for the investigation of harmful working substances also sets out the maximum workplace concentration value (MAK), the highest permissible concentration of a substance as gas, vapor or aerosol in the... 

The emission level for antimony is 50 mg/m exhaust air [44]. The MAK (maximum concentration in the workplace) values for antimony and stibine are identical at 0.05 mg/m in the FRG. The only differences lie in the peak concentrations the permitted peak level for metallic antimony is 10 times the MAK level for 30 min once per shift. In the case of stibine it is permissible for the MAK level to be exceeded by twofold for 30 min four times per shift. Antimony trioxide has been found to be unequivocally carcinogenic in animal experiments. For this reason the technical standard concentration (TSC) value in the FRG is only 0.3 mg/m calculated as antimony in total dust [45]. 

Gold poisoning is not common and occurs practically only as a result of therapeutic overdoses and as a side effect of chrysotherapy (gold therapy). Inhalation does not hurt the respiratory tracts. Levels of tolerance for the toxic effects of gold are not reported. Neither threshold limit values nor maximum permissible concentrations in the workplace are available [4]. 

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