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PRINCIPLES AND METHODS OF ASSESSING THE WORKING ENVIRONMENT

NUMBER 4 (102) 2019




  • Cadmium and its inorganic compounds – expressed as Cd – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)
    Andrzej Sapota, Adam Daragó, Marek Jakubowski, p. 5-41
  • Diesel engine exhaust, measured as elemental carbon. Documentation of proposed values of occupational exposure limits (OELs)
    Jadwiga Szymańska, Barbara Frydrych, Elżbieta Bruchajzer , p. 43-103
  • Tetrachloroethene. Documentation of proposed values of occupational exposure limits (OELs)
    Renata Soćko , p. 105-148
  • Thioacetamide – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)
    Elżbieta Bruchajzer, Jadwiga Szymańska, Barbara Frydrych , p. 149-179
  • Improving noise measurements in the work environment: a method of measuring single acoustic events and a method of conditioning input data
    Dariusz Fugiel , p. 181-209
  • Cadmium and its inorganic compounds – expressed as Cd – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)
    Andrzej Sapota, Adam Daragó, Marek Jakubowski

    Cadmium (Cd) is a white metal with a bluish tint. It forms a number of compounds occurring in them on the degree of oxidation 2+. Cadmium compounds are water-soluble to varying degrees.

    The highest risk groups include employees involved in the production of nickel-cadmium batteries, alloys, cadmium pigments as well as employees of non-ferrous metal smelters and cutting welders of metals covered with a cadmium anti-corrosion layer. According to the Central Register of Data on Exposure to Substances , Preparations, Factors or Technological Processes on Carcinogenic or Mutagenic Action, 4276 workers in Poland were exposed to cadmium and its compounds.

    Cadmium is absorbed into the body through inhalation and digestive systems. In humans, the absorption is 2–50% and 4–6%, respectively. Elimination of cadmium from the body is a slow process. The estimated half-life of cadmium is from 5 to 30 years.

    Results of studies conducted in subjects exposed to cadmium in the work environment showed that the threshold concentration of cadmium in urine, at which increased excretion of low molecular weight proteins in urine was found, is 5–10 μg/g creatinine.

    In 1993, IARC identified cadmium and its compounds as a human carcinogen (group 1). The results of experimental studies in rats provided evidence of cadmium carcinogenicity as a result of inhalation exposure.

    Cadmium is recognized by SCOEL as a category C carcinogen, i.e. as a genotoxic carcinogen for which a threshold of action (concentration) can be determined, also called a practical threshold.

    The critical organs for the toxic effects of cadmium and its inorganic compounds in humans, depending on the route of exposure, are kidneys, lungs and possibly bones. The critical effect of cadmium on kidneys is increased excretion of low molecular weight proteins in urine, while the critical effect on lungs is the carcinogenic effect.

    Inhalation studies in rats exposed to cadmium at concentrations of 30 μg Cd/m3, 13.4 μg Cd/m3 and 10 μ Cd/m3 for 18 months were used as the basis to propose TLV-TWA. The concentration of 10 μg Cd/m3 was taken as the NOAEL value. After applying the formula and taking into account the uncertainty factors with a total value of 10, the concentration of 0.001 mg/m3 (1 μg Cd/m3) was determined as the TLV-TWA value for the inhaled fraction. Biological monitoring is the best indicator of cadmium exposure. The excretion of cadmium in urine enables the assessment of cumulative cadmium in the body and takes into account all sources of cadmium exposure, including contaminated food and smoking, while the blood cadmium concentration is a measure of current exposure.

    Previous BEI values in blood and urine were 5 μg Cd/l and 5 μg Cd/g creatinine, respectively. After discussion at the 91st meeting of the Interministerial Committee for TLVs and PELs, these values were maintained as mandatory.

    This article discusses the problems of occupational safety and health, which are covered by health sciences and environ­mental engineering.



    Diesel engine exhaust, measured as elemental carbon. Documentation of proposed values of occupational exposure limits (OELs)
    Jadwiga Szymańska, Barbara Frydrych, Elżbieta Bruchajzer

    Exhaust emissions from diesel engines (SESD) are multi-component mixtures of chemical compounds resulting from incomplete combustion of fuel and engine oil. The toxic effect of exhaust gases is associated with the presence of toxic and carcinogenic compounds in them. GIS reports in 2019 that the number of employees employed in conditions constituting 0.1– 0.5 of MAC-TWA (applicable for exhaust emissions from diesel engines) in 2017 and in 2018 was 1071 and 986, respectively, while in conditions 5–1 MAC-TWA were 26 and 46, respectively. In the list of occupational diseases in the years 2013–2017, two cases of cancer were registered: in the bladder and in the larynx (exposure to PAHs present in exhaust gases). In the clinical picture of acute exhaust poisoning, irritant effects on the mucous membranes of the eyes and upper respiratory tract predominate. Eye conjunctival irritation is considered to be one of the most sensitive indicators of exhaust gas exposure. Chronic poisoning is usually seen in people who have been exposed to work for at least several years. Functional and morphological changes in the respiratory system dominate. Prolonged exposure to high concentrations of exhaust gases has resulted in accumulation of solid particles in macrophages, changes in lung cells, fibrosis and epithelial metaplasia. Exposure to exhaust fumes can exacerbate the symptoms of existing diseases, e.g., asthma, allergies. The results of epidemiological studies indicate a relationship between occupational exposure to exhaust gas emitted from diesel engines and the increased incidence of certain groups of cancers, mainly lung cancer and bladder cancer. Studies conducted on laboratory animals have shown that exposure to exhaust fumes emitted from diesel engines caused disorders of the respiratory, circulatory, nervous and immune systems. Mutagenicity tests showed positive responses in several Salmonella strains. Animal studies (prenatal and adult exposure) suggest that exposure to exhaust gas may affect male fertility. Annex III of Directive (EU) 2019/130 of the European Parliament and of the Council contains occupational exposure limit values amending Directive 2004/37/EC. For exhaust emissions from diesel engines for an 8-hour working day, this value was set at 0.05 mg/m3 (measured as elemental carbon). After 1–2 hours of human inhalation exposure to concentrations of 75–225 μg/m3 (as elemental carbon), a decrease in respiratory function parameters and the occurrence of inflammatory changes in the lungs were observed. There is insufficient data on occupational exposure to exhaust emissions from new-generation diesel engines. Therefore, it was proposed to adopt as the MAC-TWA value for exhaust emissions from diesel engines a concentration of 0.05 mg/m3 (measured as elemental carbon) included in Directive 2019/130, without setting STEL and TLV-C. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.



    Tetrachloroethene. Documentation of proposed values of occupational exposure limits (OELs)
    Renata Soćko

    Tetrachloroethene is a colorless, volatile liquid used as a chlorinated solvent in chemical laundries, in metal, machine, aerospace and paint and varnish removers. It is an intermediate for the synthesis of chemical compounds. It has found use as a medium in heat exchangers, in veterinary medicine and for disinfection of grain by fumigation.

    The production volume of tetrachloroethene in the EU is 100,000–1,000,000 t / year.

    The monograph along with the proposed hygiene standard for tetrachloroethene was re-developed due to the setting of a new limit value in biological material (BLV) in SCOEL, including measurement of tetrachloroethene concentra­tion in exhaled air and a decrease in BLV value in blood, compared to the one recommended by the Inter-Ministry Committee for OEL and OEL the value of permissible concentration of tetrachloroethene in biological material (DSB). According to SCOEL, for substances absorbed through the skin, including tetrachloroethene, there is a particular need to monitor workers' biological exposure to ensure the highest possible level of protection.

    According to the harmonized EU classification, tetrachloroethene is a category-2 carcinogen with risk phrase: Suspected of causing cancer. There is limited evidence of a carcinogenic effect of tetrachloroethene in humans and sufficient evidence of a carcinogenic effect in laboratory animals (hepatocellular carcinoma and hepatocellular adeno­ma and lymphocytic leukemia).

    In both humans and laboratory animals, the effects of acute and chronic exposure to tetrachloroethene are primarily associated with the central nervous system, liver and kidneys. Central nervous system disorders are manifested by heada­che, dizziness, impairment or abnormal coordination, and other disorders found with neuropsychological tests.

    Acute inhalation toxicity is also irritating to tetrachloroethene on the eyes and respiratory mucosa. The metabolites of tetrachloroethene are mainly responsible for its metabolites formed in the process of conjugation with glutathione in the liver and then activated in the kidneys with the participation of beta-lyase.

    The results of epidemiological studies do not clearly indicate the effect of tetrachloroethene on human reproduction or embryotoxic effects. Admittedly, effects on reproduction, embryotoxic and teratogenic effects of tetrachloroethene have been reported in some studies on laboratory animals, exposed to this substance in very high concentrations, though.

    In Poland, the maximum permissible concentration of tetrachloroethe at 85 mg/m3and the maximum permissible instantaneous concentration at 170 mg/m3 are currently in force. The determined DSB value is 1.2 mg tetrachloroethene/L capillary blood in a sample taken 15–20 min after the end of work on the 4th and 5th day of exposure.

    The critical effect of tetrachloroete are disorders in the central nervous system. The value of the hygiene standard was derived based on the LOAEL value (lowest concentration causing harmful effects) of 680 mg/m3, obtained from a study on volunteers exposed to tetrachloroethene for 1 h. In volunteers at the tested concentration headache and drowsiness and slight eye irritation were noted. The proposed MAC value for tetrachloroethene is 85 mg/m3, and the MAC value is 170 mg/m3. It was proposed to take a concentration of 0.3 mg/l capillary blood collected before the last work shift on the 5th day of work as the DSB value of tetrachloroethene. It was recommended to label tetrachloroethene with the notation "skin" (absorption of the substance through the skin may be as important as when inhaled).

    This article discusses the problems of occupational safety and health, which are covered by health sciences and environ­mental engineering.



    Thioacetamide – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)
    Elżbieta Bruchajzer, Jadwiga Szymańska, Barbara Frydrych

    Thioacetamide occurs in the form of colorless crystals with a characteristic smell of mercaptans. It was used in the past as a fumigant to prevent oranges from rotting, in rubber vulcanization and as a diesel stabilizer. It is currently used in a qualitative analysis as a source of hydrogen sulfide. According to information from the Central Register of Data on Exposure to Carcinogenic or Mutagenic Substances, Mixtures, Factors or Technological Processes in 2005-2016 from 486 to 1137 people were exposed to thioacetamide in Poland. Most of them were women. The LD50 value after intra­gastric administration of the compound to rats is 301 mg/kg. Thioacetamide is a strong hepatotoxic agent, its single dose caused hepatic necrosis. Administered repeatedly it induced liver damage, which was indicated by biochemical changes and cirrhosis. The effects of thioacetamide toxicity in chronic animal experiments indicated a relationship to exposure time. After chronic exposure of rats to thioacetamide in drinking water (at 0.03%, i.e., approximately 35 mg/kg/day) or in feed (0.5% in feed, i.e., approximately 28 mg/kg/day), hepatitis and local hepatic foci were noted after 4 months, these changes later intensified, and after 8–17 months chronic hepatitis, cirrhosis and cancer of the liver and bile ducts occurred. The results of mutagenicity and genotoxicity studies of thioacetamide are inconclusive. It can be assumed that the compound may damage genetic material in vivo after biotransformation to a highly hepa­totoxic metabolite. The metabolism of thioacetamide by S-oxidation (mainly with the participation of CYP2E1) leads to the production of sulfoxide (TASO), and then to hepatotoxic, highly reactive sulfone (TASO2). The latter is of fun­damental importance for the mechanism of toxic action of thioacetamide (by binding with hepatic macromolecules). Thioacetamide metabolites also induce oxidative stress. Because of neoplasms observed in chronic studies, Interna­tional Agency for Research on Cancer (IARC) included thioacetamide in group 2B – agents probably carcinogenic to humans. According to the CLP classification, thioacetamide is a category-1B carcinogen with a “H350 – May cause cancer” note. The hepatotoxic effects of thioacetamide in rats after repeated administration were used as the basis for determining the maximum acceptable concentration (MAC; TLV-TWA – threshold limit value-time weighted aver­age). A concentration of 1.5 mg/m3 was proposed as the MAC value. There are no bases to determine the short-term exposure limit (STEL) and the biological limit value (BLV). “Carc. 1B” marking is also proposed, as thioacetamide is a category-1B carcinogen. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.



    Improving noise measurements in the work environment: a method of measuring single acoustic events and a method of conditioning input data
    Dariusz Fugiel

    Strategy 1 (task-based measurements), described in Standard No. PN-EN ISO 9612: 2011 „Acoustics − Determination of occupational noise exposure – Engineering method „ does not always bring fully reliable results of noise measure­ments. This happens in conditions where the measured noise varies significantly because of changes in the intensity of work or changes in the duration of individual technological cycles. The same applies to short-term acoustic events characterized by high sound levels and various types of interruptions in activities performed by a worker. These re­asons, as well as mathematical simplifications adopted in Strategy 1, often cause significant errors. For such situations, in order to improve accuracy and to reduce the duration of measurements, the following methods have been proposed for measuring noise in the work environment:

    1) A method of measuring individual acoustic events (used in measuring traffic noise) adapted to the work environment by deriving mathematical formulas applied in it directly from Strategy 1, providing rules of measuring and deriving for­mulas for estimating their uncertainty.

    2) A method of conditioning input data, which, after appropriate adjustment of input data, makes it possible to calculate final results (and their uncertainties) accurately, with mathematical formulas in Strategy 1.

    The proposed methods make it possible to determine all the values and acoustic data obtained as a result of using Strategy 1. They can also be applied simultaneously at the same workstation, which is included in the presented measurement model.

    This article discusses the problems of occupational safety and health, which are covered by health sciences and environ­mental engineering.



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