Workplace concentrations

Protective measures iavolve prompt detection and adequate ventilation. Continuous monitoring is recommended to signal an evacuation alarm if the workplace concentration exceeds 70 mg/m (50 ppm) and a warning alert if it is present at 15—70 mg/m (10—50 ppm). 

Inhalation of dusts can cause metal fume fever (79,80), and ulceration or perforation of the nasal septum. Mild discomfort has been noted with workplace concentrations as low as 0.08 mg/m. The workplace standard (TLV) for copper dusts or mist is 1 mg/m and 0.2 mg/m for copper fume (81). 

Filter samples can be prepared to airborne workplace concentrations by spiking each filter with aqueous solution containing elements with concentrations gravimetrically traceable to ultrapure metals or stoidiiometricaUy well defined oxides. The amormts correspond for some of the materials to current threshold limit values of contaminants in workroom atmospheres provided that the simulated filter has been exposed to one cubic meter of air. The certified values are based on a gravimetric procedure, i.e. weight per volume composition of the primary reference material dissolved in high purity sub-dis-tiUed acids. The National Institute of Occupational Health in Oslo, Norway, has produced several batches of such materials certified for 20 elements. Additionally, information values are reported for four other elements see Table 6.2. 

Risk Degree introduced into the MPC in workplace concentration... 

MAK (Maximale Argeitsplatzkonzentration [maximum workplace concentration]) (Deutsche Forschungsgemeinschaft [German Research Association] 2000) is analogous to the ACGIH-TLV-TWA. 

Validation of the model. The Perbellini model was validated using a data set for venous blood /7-hexane values in volunteers exposed for 4 hours (Veulemans et al. 1982). The range in the study was 334-368 g/L during exposure to 204 ppm the model predicted a value within this range. After 4 hours exposure to 102 ppm, the predicted value for venous blood -hexane concentration was about 10% below that actually observed in humans. The authors also compared their own data from previous studies on the correlation between venous blood -hexane concentrations and workplace concentrations. From the correlation curve, exposure at 102 ppm would predict a venous blood concentration of 176 g/L the model predicted 182 g/L. The urinary excretion rate of 2,5-hexanedione predicted by the model was also compared to a data set from 13 workers followed for 24 hours from the beginning of a workday. 

ACGIH) also recommends a Threshold Limit Value (TLV-TWA) of 75 ppm (450 mg/m ) (ACGIH 1996). Current control technologies should limit workplace concentrations to this level. 

The Deutsche Forschungsgemeinschaft (DFG) publishes an annual report Maximale Arbeits-platzkonzentrationen (MAK) und Biologische Arbeitsstofftoleranzwerte (BAT) (maximum workplace concentrations and biological materials tolerance levels),20 to protect workers against well-defined and determined toxic or probably toxic materials in workroom air the organo-fluorine compounds included in the 1997 edition are listed in Table 3.20 These data also allow on a representative basis a comparison of acute toxic and safe concentrations of the same species (see also Section 5.2.7-)-... 

The definition of the Maximale Arbeitsplatzkonzentration MAK (maximum workplace concentration) is the highest tolerable concentration of a chemical as gas, vapor or dust in the atmosphere at a workplace to which an employee can be exposed (using the best current knowledge) without any adverse effects on the health of an individual employee within a normal 8-hour period based on an average working week of 40 hours. The fundamental exposition schemes are based on the operative mechanism of the substance, on scientific criteria for health protection, and practical experience, rather than on technical and economic feasibility. 

TWA, time-weighted average SUiL, short-term exposure limit MAK, maximum workplace concentration TLV, threshold limit value REL, recommended exposure hmit PEL, permissible exposure limit Ca, potential occupational carcinogen sk, skin notation... 

Occupational Health. Precautions have to be taken and workplace concentration limits have to be observed when handling lead- and lead chromate-containing pigments. General regulations exist for all lead-containing materials [3.151]. Concentration limits are as follows ... 

In the soon to be published new MAK-list in Germany (maximal allowable workplace concentration) ozone will be categorized as IHb which means a substance being justifiably suspected to be carcinogenic. The actual MAK value of 200 pg m 3 (= 0.1 ppm) will be suspended until it is known if ozone shows carcinogenic effects (n. n 1995). 

It is noteworthy that the styrene reference concentration (RfC) in the Integrated Risk Information System is based on the biomarker-response relationship found in workers (Mutti et al. 1984 EPA 1998). The Environmental Protection Agency (EPA) used the relationship of urinary biomarker to ambient-air concentration of workers to develop an RfC that was adjusted for the difference in exposure time between the workplace and the general population. That is a valid approach because it derives a workplace concentration-toxicity relationship in workers, which can then be adjusted for the general population to account for differences in exposure time and can take uncertainty factors into account. It is different from direct adjustment of the styrene BEI to evaluate human population biomonitoring data on styrene metabolites in urine, which would have the uncertainties described above and in Chapter 5. 

Ferguson et al. (1977) reported that some industrial workers did not voluntarily use gas masks until ammonia concentrations reached 400 or 500 ppm in the workplace. The authors also reported that, before 1951, workers were routinely subjected to continuous workplace concentrations ranging from 150 to 200 ppm. In an effort to measure the responses of human subjects to concentrations of ammonia reportedly often encountered in industrial settings, three groups of two subjects each were exposed at 25, 50, and 100 ppm ammonia for 6 h/d, 5 d/wk, for 6 weeks. These exposures followed exposure to the same concentrations for a 1-wk practice period. Observations were made of irritation to the conjunctiva of the eyes and mucous membranes of the nose and throat. Vital signs (pulse, blood pressure, respiratory rate) were measured, as were parameters of pulmonary function. With exposures up to 100 ppm there were no significant differences between experimental and control subjects in the parameters measured. The authors further demonstrated that after a period of acclimation, exposures... 

Deutsche Forschimgsgemeinschaft (2006). MAK (Maximale Arheitsplatzkonzentration - Maximum workplace concentration). List of MAK and BAT Values, Report No. 42, p. 101. 

MAK (Germany) [maximale arbeitsplatzkonzentration] maximum workplace concentration, 8-h time weighted average, German Research Association... 

Accidental ingestion and subcutaneous routes are the primary exposure pathways. The maximum workplace concentration is lOmgm . The maximum concentration in water used in fisheries is 0.1 mg 1 ... 

So-called MAK values (maximum workplace concentrations) have been defined for individual chemical substances as a preventive measure against health problems due to inhaling, which must not be exceeded at the workplace. After these preliminary remarks, the prohibition of eating and smoking at the workplace is a logical consequence. Furthermore, the following aspects have to be considered ... 

MAK-value Maximum workplace concentration, product-specific value of chemical substances defining the harmful contamination of the air at the workplace due to these substances (dimension ppm = parts per million = mg/kg). Information on MAK-values are given in the safety data sheets of the respective substances. 

In Germany, there exists no maximum allowable workplace concentration (MAK) value for arsenic and its compounds as the Commission for the Investigation of Health Hazards of Chemical Compounds... 

Norbdck et al. (1993) measured 1-week concentrations of l-octen-3-ol in the bedroom air and personal air of 39 Swedish subjects. The subjects were selected from a random population, but their willingness to participate may have been influenced by their perceptions of sick building syndrome symptoms and poor lAQ at their workplaces. Concentrations of l-octen-3-ol in bedroom air and personal air were 2 and 6 pg/m respectively (arithmetic means) with concentration ranges of <1-50 and <1-140 pg/m respectively. A significant correlation (p <0.05) was observed between the occurrence of facial itching/rashes and the concentration of l-octen-3-ol. 

There is no doubt that for developmental effects a no effect level exists. In the case of ethanol at the maximum aUowed airborne workplace concentration, no developmental effects can occur. The necessary amount can only be incorporated orally. 

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