Acrylonitrile

CAS RN:107-13-1

Exposure Summary

Acrylonitrile's production and use as a monomer or intermediate in the production of acrylic fiber, acrylonitrile-butadiene-styrene (ABS) resins, adiponitrile, nitrile rubbers, elastomers, styrene-acrylonitrile resins (SAN), acrylamide, and polyacrylonitrile may result in its release to the environment through various waste streams. Acrylonitrile has been detected in cigarette smoke and auto exhaust. If released to air, a vapor pressure of 109 mm Hg at 25 deg C indicates acrylonitrile will exist solely as a vapor in the atmosphere. Vapor-phase acrylonitrile 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 1.5 hours. Acrylonitrile does not absorb UV light at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. If released to soil, acrylonitrile is expected to have very high mobility based upon an estimated Koc of 29. Volatilization from moist soil surfaces is expected to be an important fate process based upon a Henry's Law constant of 1.38X10-4 atm-cu m/mole. Complete biodegradation of a low concentration of acrylonitrile was <2 days to 6 days depending on soil type with slow degradation reported in unacclimated soils exposed to high concentrations of acrylonitrile; these findings suggest that biodegradation may be an important environmental fate process in soil under certain conditions. If released into water, acrylonitrile is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Complete degradation in 6-20 days using various freshwater inoculums suggests that biodegradation may be an important environmental fate process in water. 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 7 hours and 4 days, respectively. An BCF of 48 suggests bioconcentration in aquatic organisms is moderate. Acrylonitrile was stable at pH 4 to 10 for 23 days indicating that hydrolysis is negligible under environmental conditions (pH 5 to 9). Occupational exposure to acrylonitrile may occur through inhalation and dermal contact with this compound at workplaces where acrylonitrile is produced or used. Monitoring data indicate that the general population may be exposed to acrylonitrile via inhalation of ambient air and dermal contact with products containing acrylonitrile. (SRC)
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