| Umweltverhalten | TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 240(SRC), determined from a log Kow of 1.83(2) and a regression-derived equation(3), indicates that cetylpyridinium bromide is expected to have moderate mobility in soil(SRC). However, quaternary ammonium compounds are known to sorb strongly, and rapidly in well-mixed systems, to a wide variety of materials (such as sewage sludge, sediment, clay)(5) and the mobility of cetylpyridinium bromide in soil may be considerably less than estimated. Volatilization of cetylpyridinium bromide from moist soil surfaces is not expected as this compound is a salt(SRC). Cetylpyridinium bromide is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 4.3X10-7 mm Hg(SRC), determined from a fragment constant method(4). Cetylpyridinium bromide is expected to biodegrade rapidly in the environment(SRC) based on studies using sewage(5,6)rates of biodegradation increased with acclimation of the microbial population(5,6).AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 240(SRC), determined from an measured log Kow of 1.83(2) and a regression-derived equation(3), indicates that cetylpyridinium bromide is not expected to adsorb to suspended solids and sediment(SRC). However, quaternary ammonium compounds are known to sorb strongly, and rapidly in well-mixed systems, to a wide variety of materials (such as sewage sludge, sediment, clay)(7)therefore, cetylpyridinium bromide should be strongly adsorbed to suspended solids and sediment in water. This compound is expected to exist in the dissociated form in the environment and therefore volatilization from water surfaces will not be an important fate process(SRC). According to a classification scheme(4), BCF values of 21, 22, and 13, measured for clams, fathead minnows, and tadpoles, respectively(5), suggest the potential for bioconcentration in aquatic organisms is low(SRC). Cetylpyridinium bromide is expected to biodegrade rapidly in the environment(SRC) based on studies using sewage(7,8)rates of biodegradation increased with acclimation of the microbial population(7,8).ATMOSPHERIC FATE: Cetylpyridinium bromide will exist as the ion in the environment and, thus, will be present solely in the particulate phase in the atmosphere. Particulate-phase cetylpyridinium bromide may be removed from the air by wet and dry deposition.(SRC) |
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