Hentriacontane

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 4.3X10+8(SRC), determined from a structure estimation method(2), indicates that hentriacontane is expected to be immobile in soil(SRC). Volatilization of hentriacontane from moist soil surfaces is expected given an estimated Henry's Law constant of 2040 atm-cu m/mole(SRC), using a fragment constant estimation method(2). However, adsorption to soil is expected to attenuate volatilization(SRC). Hentriacontane is not expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 1.40X10-11 mm Hg at 25 °C(3). Biodegradation oxygen consumption values of 8.2 and 7.6ug/mL for analogous tetracosane (C24) and hexatriacontane (C36), respectively, using a soil suspension(4) indicate that biodegradation of hentriacontane may be a slow environmental fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 4.3X10+8(SRC), determined from a structure estimation method(2), indicates that hentriacontane 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 2040 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 6.1 hours and 8.3 days, 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 15.57(2), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation oxygen consumption values of 8.2 and 7.6 ug/mL for analogous tetracosane (C24) and hexatriacontane (C36), respectively, using a soil suspension(6) indicate that biodegradation of hentriacontane 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), hentriacontane, which has an extrapolated vapor pressure of 1.40X10-11 mm Hg at 25 °C(2), will exist solely in the particulate phase in the atmosphere. Particulate-phase hentriacontane will be removed from the atmosphere by wet and dry deposition. Hentriacontane 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).

IDENTIFICATION AND USE: Hentriacontane is a higher n-alkane containing 31 carbon atoms (C31). It is used as traditional medicine and experimental therapy. HUMAN EXPOSURE AND TOXICITY: A case report described human disorder characterized by the accumulation of plant long-chain n-alkanes in viscera of a human patient. Diffuse visceral granuloma containing lipophilic crystallized material showed the presence of long-chain n-alkanes including hentriacontane. Study of n-alkane distribution in patient tissues showed a major accumulation in lumbo-aortic lymph nodes, adrenal glands, lung and liver; significantly lower amounts were detected in myocardium and kidney, whereas no detectable level was found in brain. ANIMAL STUDIES: Hentriacontane can contribute to the "paraffin liver" in cows. The very large quantities of the abnormal substance in the cow livers indicate low toxicity, and evidently accumulation over long periods of time.

Hentriacontane detections in plants used in food and medicinal applications(1). /Hentriacontane/

n-Hentriacontane detections in plants used in food and medicinal applications(1).

An ethyl acetate extract of Oryza sativa (rice) hulls yielded seven compounds: hentriacontane, 1-tetratriacontanol, beta-sitosterol, momilactone A, momilactone B, tricin (a flavonoid), and beta-sitosterol-3-O-beta-D-glucoside. The structures of these compounds were elucidated with 500 MHz nuclear magnetic resonance (NMR), using 1D and 2D spectral methods, aided by electron ionization mass spectrometry (EI-MS), fast atom bombardment mass spectrometry (FAB-MS), infrared (IR), and ultraviolet (UV) spectrophotometry. The complete 1H NMR assignments for momilactone A and B and 13C NMR assignments for tricin are discussed. To the best of our knowledge, hentriacontane, 1-tetratriacontanol, and beta-sitosterol-3-O-beta-D-glucoside were identified for the first time in rice hulls. ...

Using a structure estimation method based on molecular connectivity indices(1), the Koc of hentriacontane can be estimated to be 4.3X10+8(SRC). According to a classification scheme(2), this estimated Koc value suggests that hentriacontane is expected to be immobile in soil.

URBAN/SUBURBAN: Hentriacontane was detected in particulate air samples from Georgia Tech campus, GA at mean concentrations of 2.6 and 2.19 ng/cu m for summer 2005 and winter 2006, respectively(1). A mean hentriacontane concentration of approximately 20 ng/cu m was reported in the particulate phase of air samples collected in an urban and industrialized area in Prato, Italy during 2002(2). Hentriacontane concentrations were 19.8 and 11.7 ng/cu m in particulate phase in the summer and winter, respectively; concentrations of 0.8 and 0.7 ng/cu m were detected in the vapor phase in summer and winter, respectively; samples were collected in an urban area in Nagoya, Japan in 1991(3).

RURAL/REMOTE: Hentriacontane was detected in particulate air samples from a rural area of Yorkville, GA at mean concentrations of 0.42 and 1.34 ng/cu m for summer and winter, respectively(1).

SOURCE DOMINATED: Hentriacontane was detected in particulate air samples from an interstate highway in Georgia at a mean concentration of 4.78 and 3.66 ng/cu m for summer and winter, respectively(1). Hentriacontane was detected at 110-1200 pg/cu m with a mean of 480 pg/cu m in particulate air samples collected near a highway in Raleigh, NC; concentrations in samples collected 275 meters from the highway contained 140-1800 pg/cu m with a mean of 540 pg/cu m(2).

/CASE REPORTS/ This report deals with a new human disorder characterized by the accumulation of plant long-chain n-alkanes in viscera of a human patient. Lipid analysis of tissues from an adult male after sudden death (affected with diffuse visceral granuloma containing lipophilic crystallized material) showed the presence of abnormal compounds identified as long-chain n-alkanes with 29 (n-nonacosane), 31 (n-hentriacontane) and 33 carbons (n-tritriacontane). Study of n-alkane distribution in patient tissues showed a major accumulation in lumbo-aortic lymph nodes, adrenal glands, lung (the highest levels were found in lung granulomas) and liver; significantly lower amounts were detected in myocardium and kidney, whereas no detectable level was found in brain. On the basis of the structural composition and of the tissue distribution of the accumulated n-alkanes, their dietary (plant) origin and the pathophysiological mechanism of the storage are discussed.

AEROBIC: Oxygen consumption of 8.2 and 7.6 ug/mL over 10 days was reported for straight chain alkanes tetracosane (C24) and hexatriacontane (C36), respectively, using a soil suspension of Hudson-Collamer silt loam soil incubated in the dark at 25 °C(1). By analogy, these test results suggest that biodegradation rates are slow for long chain alkanes such as hentriacontane (C31) under these conditions(SRC).

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 similar long chain alkanes, hexacosane (C26), octacosane (C28), and triacontane (C30), which were present as components of the petroleum oil, indicate 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 such as hentriacontane (C31) may behave similarly(SRC).