Trifluoromethane

CAS RN:75-46-7

Exposure Summary

Trifluoromethane's production and use as a refrigerant, a chemical intermediate, a direct coolant for infrared detector cells and a blowing agent for urethane foams may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 35,300 mm Hg at 25 deg C indicates trifluoromethane will exist solely as a gas in the atmosphere. Gas-phase trifluoromethane will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 140-160 years. This relatively slow half-life in the lower atmosphere suggests that some trifluoromethane may gradually diffuse into the stratosphere (estimated diffusion half-life of 20 years). Trifluoromethane does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. Trifluoromethane has 20-, 100- and 500-year Global Warming Potentials of 8200-15,486, 9200-19,691 and 9900-15,547, respectively. The atmospheric life-time for trifluoromethane has been calculated to be 234-295 years. If released to soil, trifluoromethane is expected to have very high mobility based upon an estimated Koc of 32. Volatilization from moist soil surfaces is expected to be an important fate process based upon a Henry's Law constant of 0.0952 atm-cu m/mole. Trifluoromethane will volatilize from dry soil surfaces based upon its vapor pressure. Biodegradation in soil and water is not expected based on aerobic pure culture studies. If released into water, trifluoromethane is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 2.5 hours and 3.3 days, respectively. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Estimated hydrolysis half-lives of 5.1 years and 190 days at pH values of 7 and 8, respectively, suggest that hydrolysis is not expected to be an important process. Occupational exposure to trifluoromethane may occur through inhalation and dermal contact with this compound at workplaces where trifluoromethane is produced or used. Monitoring data indicate that the general population may be exposed to trifluoromethane via inhalation of ambient air, ingestion of contaminated drinking water, and dermal contact with consumer products containing trifluoromethane. (SRC)
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