1,4-ヘキサジエン

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 150(SRC), determined from a structure estimation method(2), indicates that 1,4-hexadiene is expected to have high mobility in soil(SRC). Volatilization of 1,4-hexadiene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 0.117 atm-cu m/mole(SRC), using a fragment constant estimation method(3). The potential for volatilization of 1,4-hexadiene from dry soil surfaces may exist(SRC) based upon a vapor pressure of 172.6 mm Hg(4).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 150(SRC), determined from a structure estimation method(2), indicates that 1,4-hexadiene 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 0.117 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 0.9 and 86 hours, respectively(SRC). According to a classification scheme(5), an estimated BCF of 36(SRC), from an estimated log Kow of 2.94(6), suggests the potential for bioconcentration in aquatic organisms is moderate.

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,4-hexadiene which has a vapor pressure of 172.6 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,4-hexadiene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone molecules(SRC). The half-life for the reaction in air with hydroxyl radicals is estimated to be 4.6 and 4.2 hours for 1,4-hexadiene's cis- and trans-isomers, respectively, calculated from rate constants of 8.4X10-11 and 9.1X10-11 cu cm/molecule-sec at 25 °C(SRC), respectively, determined using a structure estimation method(3). The half-life for the reaction in air with ozone is estimated to be 1.9 and 1.3 hours for 1,4-hexadiene's cis- and trans-isomers, respectively, calculated from rate constants of 1.4X10-16 and 2.1X10-16 cu cm/molecule-sec at 25 °C(SRC), respectively, determined using a structure estimation method(3). The vapor-phase reaction of 1,4-hexadiene with nitrate radicals may also be important atmospheric removal process in urban areas at night(4), but the rate of this reaction is not known.

Using a structure estimation method based on molecular connectivity indices(1), the Koc for 1,4-hexadiene can be estimated to be 150(SRC). According to a classification scheme(2), this estimated Koc value suggests that 1,4-hexadiene is expected to have high mobility in soil.

AEROBIC: No biodegradation data regarding 1,4-hexadiene were located, however data on a structurally similar compound, 1,3-butadiene are available(SRC). Laboratory studies employing pure bacterial cultures isolated from lake and soil samples were shown to degrade 1,3-butadiene to 1,2-epoxybutene(1-3). However, it is not clear what the rate of degradation is under environmental conditions(SRC). The biodegradation half-life of 1,3-butadiene in aerobic waters has been reported as 7 days and the half-life in anaerobic waters was reported as 28 days(4). These data suggest that the structurally similar 1,4-hexadiene will also undergo biodegradation under similar conditions(SRC).

An estimated BCF of 36 was calculated for 1,4-hexadiene(SRC), using an estimated log Kow of 2.94(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 1,4-hexadiene is estimated as 0.117 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 1,4-hexadiene is expected to volatilize rapidly 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 0.9 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 3.6 days(SRC). 1,4-Hexadiene's Henry's Law constant(1) indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of 1,4-hexadiene from dry soil surfaces may exist based upon a vapor pressure of 172.6 mm Hg(3).

The rate constant for the vapor-phase reaction of 1,4-hexadiene with photochemically-produced hydroxyl radicals has been estimated as 8.4X10-1 and 9.1X10-11 cu cm/molecule-sec at 25 °C(SRC) for its cis and-trans isomers, respectively, using a structure estimation method(1). This corresponds to an atmospheric half-life of about 4.6 and 4.2 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1) for the cis and trans isomers, respectively. The rate constant for the vapor-phase reaction of 1,4-hexadiene with ozone has been estimated as 1.4X10-16 and 2.1X10-16 cu cm/molecule-sec at 25 °C(SRC)for its cis and trans-isomers, respectively, using a structure estimation method(1). This corresponds to atmospheric half-lives of about 1.9 and 1.3 hours for the cis and trans-isomers, respectively, at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). The vapor- phase reaction of 1,4-hexadiene with nitrate radicals may also be important atmospheric removal process in urban areas at night(3), but the rate of this reaction is not known. 1,4-Hexadiene is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(4).

1,4-Hexadiene's production and use as a chemical intermediate for synthetic elastomers may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 172.6 mm Hg at 25 °C indicates 1,4-hexadiene will exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,4-hexadiene will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone molecules. The half-life for the reaction in air with hydroxyl radicals is estimated to be 4.6 hours for the cis-isomer of 1,4-hexadiene and 4.2 hours for the trans-isomer of 1,4-hexadiene. The half-life for the reaction in air with ozone is estimated to be 1.9 hours for the cis-isomer of 1,4-hexadiene and 1.3 hours for the trans-isomer of 1,4-hexadiene. The vapor-phase reaction of 1,4-hexadiene with nitrate radicals may also be important atmospheric removal process in urban areas at night, but the rate of this reaction is not known. If released to soil, 1,4-hexadiene is expected to have high mobility based upon an estimated Koc of 150. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 0.117 atm-cu m/mole. 1,4-Hexadiene may volatilize from dry soil surfaces based upon its vapor pressure. If released into water, 1,4-hexadiene is not expected to adsorb to suspended solids and sediment based upon its estimated Koc. No biodegradation data were located for 1,4-hexadiene, but the biodegradation half-life of 1,3-butadiene in aerobic waters has been reported as 7 days and the half-life in anaerobic waters was reported as 28 days. These data suggest that 1,4-hexadiene, a structurally similar compound, will also be biodegraded in aquatic systems. 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 0.9 and 86 hours, respectively. An estimated BCF of 36 suggests the potential for bioconcentration in aquatic organisms is moderate. Hydrolysis is not expected to be an important environmental fate process for 1,4-hexadiene due to a lack of hydrolyzable functional groups. Occupational exposure to 1,4-hexadiene may occur through inhalation and dermal contact with this compound at workplaces where 1,4-hexadiene is produced or used. (SRC)

Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. 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. Administer activated charcoal ... . /Aliphatic hydrocarbons and related compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious or in respiratory rest. 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 ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Aliphatic hydrocarbons and related compounds/