Pentane

n-Pentane was detected in 8 of 12 samples of mothers breast milk from the cities of Bayonne NJ, Jersey City NJ, Bridgeville PA and Baton Rouge LA(1).

EC50; Species: Daphnia magna (Water Flea) age 4-6 days, length 1.5 mm; Conditions: freshwater, static, 23 °C, pH 6-7, dissolved oxygen 5-9 mg/L; Concentration: 135 mmol/cu m for 48 hr (95% confidence interval: 111-164 mmol/cu m); Effect: intoxication, immobilization /> or =97% purity/

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), n-pentane, which has a vapor pressure of 514 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase n-pentane 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 3 days(3), calculated from its rate constant of 3.94X10-12 cu cm/molecule-sec at 25 °C(4). n-Pentane does not contain chromophores that absorb at wavelengths >290 nm(5) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of n-pentane can be estimated to be 72(SRC). According to a classification scheme(2), this estimated Koc value suggests that n-pentane is expected to have high mobility in soil.

The degradation of n-alkanes by microorganisms is similar to the degradation of fatty acids. The terminal methyl group is enzymatically oxidized by incorporation of molecular oxygen by a monooxygenase producing a primary alcohol with further oxidation to an acid group, although involvement of a dioxygenase is also postulated. Once the fatty acid is produced, it is degraded into 2-carbon units via the beta-oxidation pathway. ... Another pathway for n-alkane degradation that is encountered less often is the oxidation of both terminal carbons to form a dioic acid with subsequent beta-oxidation. Subterminal oxidation of the 2-carbon atom is seen mainly in C3-C6 alkanes. ... A dehydrogenation of the n-alkane may also occur yielding an alkene which is then converted to an alcohol, although th...

An estimated BCF of 80 was calculated for n-pentane(SRC), using a log Kow of 3.39(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 n-pentane is 1.25 atm-cu m/mole(1). This Henry's Law constant indicates that n-pentane 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 2.5 hours(3). 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 3.4 days(3). n-Pentane's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). n-Pentane is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 514 mm Hg(4).

Photooxidation of n-pentane by ultraviolet light in aqueous medium at 50 °C: 31% degradation to carbon dioxide after 24 hr

SURFACE WATER: n-Pentane was identified, not quantified, in Delaware River water at Philadelphia, PA(1). n-Pentane was listed as a contaminant present in the waters of Lake Ontario(2). The Inner Harbor Navigation Canal of Lake Pontchartrain at New Orleans, LA was found to contain n-pentane at an average concentration for 8 samples of 2.4 ppb on May 6, 1980(3). All 8 near surface sea water samples from the intertropical Indian Ocean contained unspecified amounts of n-pentane(4).

n-Pentane was identified as a volatile constituent of freshly cooked fried chicken(1) and chickpeas(2).

n-Pentane was detected in 8 of 12 samples of mothers breast milk from the cities of Bayonne NJ, Jersey City NJ, Bridgeville, PA and Baton Rouge LA(1).

n-Pentane was identified, not quantified, in the volatile component of kiwi fruit (Actinidia chinensis) flowers(1). The compound was detected, not qunatified in the stem of kohlrabi (Brassica oleracea var. gongylodes) in soybean plant (Glycine max)(2).

Data from Sept 2, 1979 identified pentane as a gaseous emission of the vehicle traffic through the Allegheny Mountain Tunnel of the Pennsylvania Turnpike(1). The average exhaust from 67 gasoline fueled vehicles was found to contain n-pentane at a concentration 3.3% by weight(2). n-Pentane from car exhaust ranged in concentration from 0.03 to 0.07 ppm with an average for 8 samples of 0.04 ppm(3). The average concentration of n-pentane for the exhaust of 46 automobiles was 1.7 weight % of total hydrocarbon content according to both the Federal test procedure and the New York City cycle(4). The emission of n-pentane from automobiles inside and outside a roadway tunnel in Los Angeles, CA was measured as 230 mg/L(5). The emission rate of n-pentane from the tailpipes of diesel powered trucks...

The substance is toxic to aquatic organisms. The substance may cause long-term effects in the aquatic environment. It is strongly advised not to let the chemical enter into the environment.

n-Pentane is a constituent in the paraffin fraction of crude oil and natural gas(1).

n-Pentane's production and use as a general laboratory solvent, a solvent for polymerization reactions, and as a raw material in the synthesis of olefins and other industrial chemicals(1) may result in its release to the environment through various waste streams(SRC). The vast majority of n-pentane is released to the environment through the manufacture, use, and disposal of many products associated with the petroleum industry and the combustion of gasoline(1,2).

n-Pentane was detected in 3 of 4 sediment samples from Walvis Bay of the Namibian shelf of SW Africa at concentrations of 0.12, 0.19 and 0.78 ng/g(1).

n-Pentane levels inside the cabins of highway patrol vehicles were measured at an ambient (northern Raleigh, NC) and a roadside location (Wake Co near major traffic routes), respectively. Measurements from two cars were taken during 25 workshifts (3PM to midnight) in the autumn of 2001 in Chapel Hill, NC. The compound was not detected in the patrol cars but was detected with a cluster analysis distance values of 0.2 at the roadside site(1).

Analysis of six fine (foliar) fuels common to fire-prone US ecosystems revealed the presence of n-pentane in the primarily carbonaceous PM2.5 particulate matter as follows (biomass type (mg/kg biomass burned): in Pinaceae - loblolly pine (27.8); Western hemlock (28.0; Ponderosa pine (54.0); in mixed ecosystems: Acereae/Fagaceae (21.3); Palmea/Pinaceae (18.4): Poceae/Pinaceae (23.7)(1). n-Pentane emission factors from various cookstoves used in China were as follows (mg/kg dry fuel (stove type; "v" indicates flue)): 0.101 (Honey metal-v); 1.13 (Honey-metal): 0.183 (Honey-imp); 1.74 (coal briquette-metal); 167 (wash coal-metal-v; 60.8 (coal-metal-v); 2.20 (coal-brick-v); 1.64 (wheat-brick-v); 2.93 (maize-brick-v); 0.249 (maize-imp-v); 0.300 (coal gas-traditional); 0.982 (natural gas-tradi...

n-Pentane's production and use as a general laboratory solvent, a solvent for polymerization reactions, and as a raw material in the synthesis of olefins and other industrial chemicals may result in its release to the environment through various waste streams. n-Pentane is also a component of natural gas and crude oil. The vast majority of n-pentane is released to the environment through the manufacture, use, and disposal of many products associated with the petroleum industry and the combustion of gasoline. If released to air, a vapor pressure of 514 mm Hg at 25 °C indicates n-pentane will exist solely as a vapor in the ambient atmosphere. Vapor-phase n-pentane will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reactio...

Pentane is a central nervous system depressant and can cause anorexia, euphoria, dizziness, headache, depression, confusion, inability to concentrate, anoxia, narcosis, and loss of consciousness and coma at high concentrations. Contact with the skin results in cause drying, erythema, hyperpigmentation, hyperemia, dermatitis, burning pain, and blisters. (T14, T29, A600)

Treatment is mainly symptomatic and supportive. Gastric lavage, emesis, and the administration of activated charcoal should be avoided, as vomiting increases the risk of aspiration. (A600)

Pentane is a weak cardiac sensitizer of the dog heart to epinephrine.

Eyes, skin, respiratory system, central nervous system

LD50: 446 mg/kg (Intravenous, Mouse) (T14) LC50: 364 g/m3 over 4 hours (Inhalation, Rat) (T14)

Pentane is a central nervous system depressant and can cause loss of consciousness and coma at high doses. Ingestion may cause pulmonary toxicity due to pentane aspiration, including chemical pneumonitis, acute lung injury, and hemorrhage. Cardiovascular effects may include ventricular dysrhythmias and sudden death. (T29, A600)

Neurotoxin - Acute solvent syndrome

Oral (T29); inhalation (T29); dermal (T29)

Pentane is a central nervous system depressant. It affects the peripheral nervous system through demyelinization and axonal degeneration. (T29)

Inhalation Subchronic Reference Concentration Reference: PPRTV Current

Pentane is found in gasoline, which is possibly carcinogenic to humans (Group 2B). (L135)

LD50 Mouse intravenous 446 mg/kg.

Persons with skin disorders may be more susceptible to the effects of this agent. ... In persons with impaired pulmonary function, especially those with obstructive airway diseases, the breathing of pentane might cause exacerbation of symptoms due to its irritant properties.

Mutagen

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag-valve-mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously.Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Aliphatic hydrocarbons and re...

Mutagen

Reference: Smith, C.D. and Nowell, L.H., 2024. Health-Based Screening Levels for evaluating water-quality data (3rd ed.). DOI:10.5066/F71C1TWP