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

Abstract

etrachloroethene 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/m3 and 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.