beta-Bromostyrene

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 960(SRC), determined from a structure estimation method(2), indicates that beta- bromostyrene is expected to have low mobility in soil(SRC). Volatilization of beta-bromostyrene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.5X10-4 atm-cu m/mole(SRC), using a fragment constant estimation method(3). beta-Bromostyrene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 0.12 mm Hg(SRC), determined from a fragment constant method(4).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 960(SRC), determined from a structure estimation method(2), indicates that beta-bromostyrene is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 5.5X10-4 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 6 hrs and 6 days, respectively(SRC). According to a classification scheme(5), an estimated BCF of 3(SRC), from an estimated log Kow of 3.15(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), beta-bromostyrene, which has an estimated vapor pressure of 0.12 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely as a vapor in the ambient atmosphere(SRC). Vapor-phase beta-bromostyrene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone(SRC); the half-lives for these reactions in air are estimated to be 22 hrs and 6 days, respectively(SRC), calculated from rate constants of 1.7X10-11 cu cm/molecule-sec and 2.2X10-18 cu cm/molecule-sec (cis- and trans- avg), respectively, at 25 °C(SRC) and derived using a structure estimation method(3).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for beta-bromostyrene can be estimated to be 960(SRC). According to a classification scheme(2), this estimated Koc value suggests that beta-bromostyrene is expected to have low mobility in soil(SRC).

An estimated BCF of 3 was calculated for beta-bromostyrene(SRC), using an estimated log Kow of 3.15(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for beta-bromostyrene is estimated as 5.5X10-4 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that beta-bromostyrene is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 6 hrs(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 6 days(SRC). beta-Bromostyrene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). beta-Bromostyrene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 0.12 mm Hg(SRC), determined from a fragment constant method(3).

The rate constant for the vapor-phase reaction of beta-bromostyrene with photochemically-produced hydroxyl radicals has been estimated as 1.7X10-11 cu cm/molecule-sec (cis- and trans- avg) at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 22 hrs an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of beta-bromostyrene with ozone has been estimated as 2.2X10-18 cu cm/molecule-sec (cis- and trans- avg) at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 6 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). beta-Bromostyrene is not expected to undergo hydrolysis in the environment due to the lack of hydrolysis of vinyl bromides(3).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 20,488 workers (12,772 of these are female) are potentially exposed to beta-bromostyrene in the US(1). Occupational exposure to beta-bromostyrene may occur through dermal contact with this compound at workplaces where beta-bromostyrene is produced or used(SRC). The general population may be exposed to beta-bromostyrene via dermal contact with consumer products(2) containing beta-bromostyrene(SRC).

beta-Bromostyrene's production and in use as a food additive and fragrance in consumer products may result in its release to the environment through various waste streams. If released to air, an estimated vapor pressure of 0.12 mm Hg at 25 °C indicates beta-bromostyrene will exist solely as a vapor in the ambient atmosphere. Vapor-phase beta-bromostyrene will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone; the half-lives for these reactions in air are estimated to be 22 hrs and 6 days, respectively. If released to soil, beta-bromostyrene is expected to have low mobility based upon an estimated Koc of 960. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 5.5X10-4 atm-cu m/mole. If released into water, beta-bromostyrene is 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 estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 6 hrs and 6 days, respectively. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to occur due to the lack of hydrolysis of vinyl bromides. Occupational exposure to beta-bromostyrene may occur through dermal contact with this compound at workplaces where beta-bromostyrene is produced or used. The general population may be exposed to beta-bromostyrene via dermal contact with consumer products containing beta-bromostyrene. (SRC)