1,2-Dibromo-1,1-dichloroethane

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 97(SRC), determined from a structure estimation method(2), indicates that 1,2-dibromo-1,1-dichloroethane is expected to have high mobility in soil(SRC). Volatilization of 1,2-dibromo-1,1-dichloroethane from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.6X10-4 atm-cu m/mole(SRC), using a fragment constant estimation method(3). 1,2-Dibromo-1,1-dichloroethane is expected to hydrolyze in moist soils based upon an estimated hydrolysis rate constant of 1.5 l/mol sec; half-lives of 5 and 52 days at pH 7 and 8, respectively(4). 1,2-Dibromo-1,1-dichloroethane is expected to volatilize slowly from dry soil surfaces(SRC) based upon a vapor pressure of 0.9 mm Hg(5).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 97(SRC), determined from a structure estimation method(2), indicates that 1,2-dibromo-1,1-dichloroethane is not 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 1.6X10-4 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 7.5 hrs and 9 days, respectively(SRC). Under basic conditions, however, hydrolysis of 1,2-dibromo-1,1-dichloroethane will compete with volatilization from surface waters(SRC). A base-catalyzed second-order hydrolysis rate constant of 1.5 L/mole-sec(SRC) was estimated using a structure estimation method(5); this corresponds to half-lives of 52 and 5 days at pH values of 7 and 8, respectively(5). According to a classification scheme(6), an estimated BCF of 50(SRC), from an estimated log Kow of 3(7) and a regression-derived equation(8), suggests the potential for bioconcentration in aquatic organisms is moderate(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,2-dibromo-1,1-dichloroethane, which has a vapor pressure of 0.9 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,2-dibromo-1,1-dichloroethane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 890 days(SRC), calculated from its rate constant of 1.8X10-14 cu cm/molecule-sec at 25 °C(SRC) determined using a structure estimation method(3).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for 1,2-dibromo-1,1-dichloroethane can be estimated to be 97(SRC). According to a classification scheme(2), this estimated Koc value suggests that 1,2-dibromo-1,1-dichloroethane is expected to have high mobility in soil.

An estimated BCF of 50 was calculated for 1,2-dibromo-1,1-dichloroethane(SRC), using an estimated log Kow of 3(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is moderate(SRC).

The Henry's Law constant for 1,2-dibromo-1,1-dichloroethane is estimated as 1.6X10-4 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 1,2-dibromo-1,1-dichloroethane 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 7.5 hrs hours(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 9 days(SRC). 1,2-Dibromo-1,1-dichloroethane's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 1,2-Dibromo-1,1-dichloroethane is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 0.9 mm Hg(3).

The rate constant for the vapor-phase reaction of 1,2-dibromo-1,1-dichloroethane with photochemically-produced hydroxyl radicals has been estimated as 1.8X10-14 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 890 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). A base-catalyzed second-order hydrolysis rate constant of 1.5 L/mole-sec(SRC) was estimated using a structure estimation method(2); this corresponds to half-lives of 52 and 5 days at pH values of 7 and 8, respectively(2). 1,2-Dibromo-1,1-dichloroethane is not expected to directly photolyze due to the lack of absorption in the environmental UV spectrum (>290 nm).

DETECTED IN FINISHED DRINKING WATER ... /FROM TABLE/

DRINKING WATER: Dibromodichloroethane (isomer not specified) was detected in finished drinking water samples from 2 out of 3 New Orleans area water plants during Aug 1974(1).

1,2-Dibromo-1,1-dichloroethane's production and use as research chemical may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 0.9 mm Hg at 25 °C indicates 1,2-dibromo-1,1-dichloroethane will exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,2-dibromo-1,1-dichloroethane 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 890 days. If released to soil, 1,2-dibromo-1,1-dichloroethane is expected to have high mobility based upon an estimated Koc of 97. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 1.6X10-4 atm-cu m/mole. 1,2-Dibromo-1,1-dichloroethane may volatilize from dry soil surfaces based upon its vapor pressure. If released into water, 1,2-dibromo-1,1-dichloroethane 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 estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 7.5 and 9 hrs, respectively. An estimated BCF of 50 suggests the potential for bioconcentration in aquatic organisms is moderate. A base-catalyzed second-order hydrolysis is expected with half-lives of 52 and 5 days at pH values of 7 and 8, respectively. Occupational exposure to 1,2-dibromo-1,1-dichloroethane may occur through inhalation and dermal contact with this compound at workplaces where 1,2-dibromo-1,1-dichloroethane is produced or used. (SRC)

Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/