Heptane

n-Heptane was detected in 7 of 12 samples of mothers breast milk from the cities of Bayonne, NJ; Jersey City, NJ; Bridgeville, PA; and Baton Rouge, LA(1). n-Heptane has also been detected in mother's milk collected from Pittsburgh, PA(2). The concentrations of n-heptane in the samples from these studies were not reported(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), n-heptane, which has a vapor pressure of 46 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase n-heptane 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 2.2 days(SRC), calculated from its rate constant of 7.15X10-12 cu cm/molecule-sec at 25 °C(3). n-Heptane does not contain chromophores that absorb at wavelengths >290 nm(4) 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-heptane can be estimated to be 240(SRC). According to a classification scheme(2), this estimated Koc value suggests that n-heptane is expected to have moderate mobility in soil.

AEROBIC: n-Heptane, present at 100 mg/L, reached 101% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test(1). In a study determining the primary aerobic biodegradation of biodiesel B20 fuel, the calculated half-life of n-heptane contained in the mixture was 2.3 days using unacclimated inocula from a rainwater detention pond(2). The theoretical oxygen demand of benzene acclimated activated sludge for n-heptane was 0.7, 4.3 and 23.4% after 6, 24, and 72 hr, respectively(3). One mg of n-heptane and 1 ml of a 1:10 suspension of Hudson-Collamer silt loam soil in mineral salts media were incubated in the dark at 25 °C(4). Controls without n-heptane were used to determine the net oxygen consumed(4). The average theoretical biological oxygen...

An estimated BCF of 550 was calculated in fish for n-heptane(SRC), using a log Kow of 4.66(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high(SRC), provided the compound is not metabolized by the organism(SRC).

In a study quantifying the passive volatilization of a synthetic gasoline and its individual components in three air-dried soils over a period of up to 16 days, n-heptane had a volatilization half-life of approximately 10 hours in a loamy sand at a depth of 50 mm(1). Using different soil types, n-heptane, at a depth of 50 mm, volatilized first from sand, followed by a loamy sand and finally a silt loam, showing that as the particle size of the soil decreased and the clay and organic content matter increased, the volatilization rate decreased(1). Complete volatilization of n-heptane from a tray containing a gasoline pool thickness of 7 mm at a temperature of 18.5 °C occurred after approximately 5.6 hours(1). In a study in which a jet fuel mixture was incubated in freshwater from the Esca...

The rate constant for the vapor-phase reaction of n-heptane with photochemically-produced hydroxyl radicals is 7.15X10-12 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 2.2 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(2). n-Heptane is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(3). n-Heptane 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).

SURFACE WATER: Only trace quantities of n-heptane were detected in open surface waters and from an unpolluted coastal area of the north central Gulf of Mexico(1). The n-heptane concentration ranged from 2 to 5 ng/L for 6 surface water samples collected at coastal areas of the north central Gulf of Mexico under anthropogenic influence(1). n-Heptane was detected in 7 of 8 surface water samples in the Gulf of Mexico ranging in concentration from 0.1 to 4.1 ng/L with an average concentration of 1.9 ng/L(2).

The concentration of n-heptane measured in the volatile components of duck meat, duck fat, cantonese style roasted duck, and cantonese style roasted duck gravy were 1.34, 3.47, 17.29, and 6.51 ppb on a wet basis, respectively(1). n-Heptane was identified (unspecified concentrations) in both the noncondensable volatile fraction and in the condensable lipid fraction headspace of raw beef(2). n-Heptane has been detected in dry-cured hams at different stages of the manufacturing process; however, the concentrations were not specified(3). n-Heptane was identified as a volatile component of fried bacon(4), roasted filberts(5) and nectarines(6). n-Heptane has been detected (unspecified concentrations) in boiled Chinese Chestnuts(7). n-Heptane has been identified in headspace samples of heated...

n-Heptane was detected in 7 of 12 samples of mothers breast milk from the cities of Bayonne, NJ; Jersey City, NJ; Bridgeville, PA; and Baton Rouge, LA(1). n-Heptane has also been detected in mother's milk collected from Pittsburgh, PA(2). The concentrations of n-heptane in the samples from these studies were not reported.

/AQUATIC SPECIES/ Young Coho salmon /Oncorhynchus kisutch/: no significant mortalities when applied in amounts up to 100 ppm, after 96 hr in artificial sea water at 8 °C

n-Heptane was identified as a volatile constituent in kiwi fruit flowers collected in Kawanishishi, Hyogo, Japan(1).

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

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

n-Heptane was detected in Walleye fish tissues from Lake St Clair, MI.

n-Heptane's production and use as a solvent, in organic synthesis, and as a standard for octane-rating determinations(1) may result in its release to the environment through various waste streams(SRC). The presence of n-heptane in gasoline and petroleum based products(2,3) may result in its release through the use of these substances as well.

SEDIMENT: n-Heptane was detected in 3 of 4 sediment samples from Walvis Bay of the Namibian shelf of SW Africa at concentrations of 0.12, 0.13 and 0.15 ng/g(1). n-Heptane has been detected (unspecified concentrations) in sediment collected from the Manora Channel of Karachi, Pakistan(2).

The atmospheric concentration of n-heptane ranged from 20 to 14000 ug/cu m for the vulcanization area of a shoe sole manufacturing plant, and from 3 to 500 ug/cu m for the vulcanization area and 0 to 70 ug/cu m for the extrusion area of a tire retreading factory(1). n-Heptane was detected in the workplace atmospheres of 336 businesses in Belgium with a frequency of occurrence of 11% for those that utilize printing pastes; 16% where painting took place; 65% of the automobile repair shops and 3% for sites where various materials such as varnishes are employed(2). A total of 89 employees who spray paints or glues on their jobs for 3 companies were exposed to n-heptane at an average concentration of 0.1 ppm(3). The workers of 7 out of 9 printing shops tested in Amsterdam were exposed to an...

The weighted average percentage of n-heptane among other volatile hydrocarbons measured in whole gas of various octanes was 0.85%(1). The concentration of n-heptane in gasoline has been measured to be 9,700 ug/g(2). The concentration of n-heptane in coal used by coal-fired power plants has been reported to be 1.07 ug/g(3).

n-Heptane's production and use as a solvent, in organic synthesis, and as a standard for octane-rating determinations may result in its release to the environment through various waste streams. The presence of n-heptane in gasoline and petroleum based products may result in its release through the use of these substances as well. n-Heptane is also a constituent in the paraffin fraction of crude oil and natural gas. If released to air, a vapor pressure of 46 mm Hg at 25 °C indicates n-heptane will exist solely as a vapor in the atmosphere. Vapor-phase n-heptane 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 2.2 days. n-Heptane does not contain chromophores that absorb at wavelengths...

Heptane affects the central nervous system and may cause lightheadedness, giddiness, stupor, vertigo, incoordination, loss of appetite, nausea, and unconsciousness. Direct skin contact with heptane may cause pain, burning, and itching. (T29)

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)

Skin, respiratory system, central nervous system

LD50: 222 mg/kg (Intravenous, Mouse) (T14) LC50: 75 g/m3 over 2 hours (Inhalation, Mouse) (T14)

Petroleum distillates are aspiration hazards and may cause pulmonary damage, central nervous system depression, and cardiac effects such as cardiac arrhythmias. They may also affect the blood, immune system, liver, and kidney. (A600, L1297)

Neurotoxin - Acute solvent syndrome

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

Petroleum distillates are central nervous system depressants and cause pulmonary damage. (A600)

Oral Subchronic Chronic Reference Dose Reference: PPRTV Current

The fatal concentration of heptane in humans has been reported as 16,000 ppm. /SRP: Time not specified./

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

LC50 Rat inhalation 103 mg/cu m/4 hr

Persons with preexisting 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 heptane might cause exacerbation of symptoms due to its irritant properties.

Soil Saturation Concentration (mg/kg): 5.79e+01

CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: No human data and no animal data available. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: None.

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...

Soil Saturation Concentration (mg/kg): 5.79e+01