Hexatriacontane

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 8.7X10+9(SRC), determined from a structure estimation method(2), indicates that hexatricontane is expected to be immobile in soil(SRC). Volatilization of hexatricontane from moist soil surfaces is expected to be a fate process(SRC) given an estimated Henry's Law constant of 8400 atm-cu m/mole(SRC), using a fragment constant estimation method(2). However, adsorption to soil is expected to attenuate volatilization(SRC). Hexatricontane is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 9.2X10-9 mm Hg at 25 °C(SRC), determined from a fragment constant method(2). A biodegradation oxygen consumption value of 7.6 ug/mL using a soil suspension(3) indicates that biodegradation of hexatriacontane may be a slow environmental fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 8.7X10+9(SRC), determined from a structure estimation method(2), indicates that hexatriacontane 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 8400 atm-cu m/mole(SRC), developed using a fragment constant estimation method(1). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 6.6 and 210 hours, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is more than 2 years if adsorption is considered(4). According to a classification scheme(5), an estimated BCF of 3(SRC), from an estimated log Kow of 18.02(2), suggests the potential for bioconcentration in aquatic organisms is low(SRC). A biodegradation oxygen consumption value of 7.6 ug/mL using a soil suspension(3) indicates that biodegradation of hexatriacontane may be a slow environmental fate process in water(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), hexatriacontane, which has an estimated vapor pressure of 9.2X10-09 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase hexatriacontane may be removed from the air by wet and dry deposition(SRC). Hexatriacontane does not contain chromophores that absorb at wavelengths >290 nm(3) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

Hexatriacontane detections in plants used in food and medicinal applications(1). /Hexatriacontaine/[Table#8392]

n-Hexatriacontane detections in plants used in food and medicinal applications(1).[Table#8393]

Using a structure estimation method based on molecular connectivity indices(1), the Koc of hexatriacontane can be estimated to be 8.7X10+9 (SRC). According to a classification scheme(2), this estimated Koc value suggests that hexatriacontane is expected to be immobile in soil.

URBAN/SUBURBAN: A mean hexatriacontane concentration of approximately 1 ng/cu m was reported in the particulate phase of air samples collected in an urban and industrialized area in Prato, Italy during 2002(1). Hexatriacontane concentrations were 2.8 and 2.0 ng/cu m in particulate phase in the summer and winter, respectively, and 0.2 ng/m3 in vapor phase in both summer and winter; samples were collected in an urban area in Nagoya, Japan in 1991(2).

AEROBIC: Oxygen consumption of 7.6 ug/mL over 10 days was reported for hexatriacontane using a soil suspension of Hudson-Collamer silt loam soil incubated in the dark at 25 °C(1).

PURE CULTURE: Using 5 different marine bacterial strains and 4 different nitrogen sources, biodegradation of petroleum oil was examined under aerobic conditions at 26 °C for 10 days. Data reported for hexacosane (C26), octacosane (C28), and triacontane (C30), which were present as components of the petroleum oil, indicatd that these compounds were degraded by 4 of 5 bacterial strains with certain nitrogen sources and consumption ranged from 5 to 96%(1). Other long chain alkanes like hexatriacontane (C36) may behave similarly(SRC).

An estimated BCF of 3 was calculated in fish for hexatriacontane(SRC), using an estimated log Kow of 18.02(1) and a regression-derived equation(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for hexatriacontane is estimated as 8400 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that hexatriacontane 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 6.6 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). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The volatilization half-life from a model pond is greater than 2 years when adsorption is considered(3). Hexatriacontane's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). Hexatriacontane is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 9.2X10-9 mm Hg(SRC), determined from a fragment constant method(1).

Hexatriacontane is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(1). Hexatriacontane does not contain chromophores that absorb at wavelengths >290 nm(1) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

According to the 2012 TSCA Inventory Update Reporting data, there are 0 reporting facilities for hexatriacontane(1).

Occupational exposure may be through inhalation and dermal contact with hexatricontane at workplaces where coal and petroleum derived substances are produced or used or where combustion processes are extensive. The general population may be exposed to hexatriacontane through inhalation of polluted air, ingestion of food and contact with water contaminated by combustion effluents. (SRC)