2,7-Dimethylpyrene

230.3 g/mol

230.30

239-762-6

0E465NIX94

DTXSID20166132

0 Ų

log Kow = 6.03 (est)

187-190 °C

In water, 4.567X10-3 mg/L at 25 °C (est)

6.86X10-8 mm Hg at 25 °C (est)

Henry's Law constant = 3.38X10-6 atm-cu m/mol at 25 °C (est)

Hydroxyl radical reaction rate constant = 1.60X10-10 cu cm/molec-sec at 25 °C (est)

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.|SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Strong oxidizers.

Respirator Recommendations: At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration: /Coal tar pitch volatiles/[Table#3883]|Respirator Recommendations: Escape conditions: /Coal tar pitch volatiles/[Table#3884]

The worker should wash daily at the end of each work shift, and prior to eating, drinking, smoking, etc. /Coal tar pitch volatiles/|Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises. /Coal tar pitch volatiles/|SRP: Contaminated protective clothing should be segregated in a manner such that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. The completeness of the cleaning procedures should be considered before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at the end of shift, but should remain at employee's place of work for cleaning.

Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 0.2 mg/cu m. /Coal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene/

Recommended Exposure Limit: 10 Hr Time-Weighted Avg: 0.1 mg/cu m (cyclohexane-extractable fraction). /Coal tar pitch volatiles/|NIOSH considers coal tar pitch volatiles to be potential occupational carcinogens. NIOSH usually recommends that occupational exposures to carcinogens be limited to the lowest feasible concentration. /Coal tar pitch volatiles/

2,7-Dimethylpyrene was detected at 0.906 mg/g polystyrene (7.24% of total PAHs detected) in particulate emissions in polystyrene combustion(1). 2,7-Dimethylpyrene is reported to have occurrence in gasoline or diesel exhaust(2).

Methyl and alkyl pyrenes have been identified as constituents of tobacco smoke(1). 2,7-Dimethylpyrene is reported to have occurrence in water, air, tobacco smoke, and gasoline or diesel exhaust(2).

IDENTIFICATION AND USE: 2,7-Dimethylpyrene is a polynuclear aromatic hydrocarbon. HUMAN EXPOSURE AND TOXICITY: There are no data available. ANIMAL STUDIES: There are no data available.

Methylpyrenes have been detected in crude oils and in sedimentary rock extracts with Early Paleozoic and Cenozoic origins(1). /Methylpyrenes/

Polycyclic aromatic hydrocarbons (PAHs), such as methylpyrenes, occur as ubiquitous products of incomplete combustion of fossil fuels, wood, diesel oils and gasoline fuels(1). 2,7-Dimethylpyrene's occurrence in gasoline and diesel exhaust(2) will release the compound directly to the environment(SRC). Methylpyrenes occur in tobacco smoke(2,3).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 140,000(SRC), determined from a structure estimation method(2), indicates that 2,7-dimethylpyrene is expected to be immobile in soil(SRC). Volatilization of 2,7-dimethylpyrene from moist soil surfaces may occur given an estimated Henry's Law constant of 3.4X10-6 atm-cu m/mole(SRC), using a fragment constant estimation method(2). However, adsorption to soil is expected to attenuate volatilization(SRC). 2,7-Dimethylpyrene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 6.9X10-8 mm Hg at 25 °C(SRC), determined from a fragment constant method(2). PAHs with four or more rings, such as 2,7-dimethylpyrene, are generally expected to be resistant to biodegradation(3). By analogy to pyrene, biodegradation is expected to occur slowly in soils, with estimated half-lives ranging from several weeks to years(4,5). Faster biodegradation rates occur with exposure to acclimated microbes(6). Degradation of analogous 1-methylpyrene during a bioslurry method reached 38% after 29 days of incubation using a contaminated soil from a former gasworks(7). By analogy to pyrene which absorbs strongly at wavelengths >290 nm(8), 2,7-dimethylpyrene is expected to be susceptible to direct photolysis on surfaces exposed to sunlight(SRC).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 140,000(SRC), determined from a structure estimation method(2), indicates that 2,7-dimethylpyrene 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 3.4X10-6 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 17 and 126 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 >10 years if adsorption is considered(4). According to a classification scheme(5), an estimated BCF of 4400(SRC), from an estimated log Kow of 6.03(2) and a regression-derived equation(2), suggests the potential for bioconcentration in aquatic organisms is very high, provided the compound is not metabolized by the organism(SRC). However, 2,7-dimethylpyrene may not bioconcentrate in aquatic organisms which contain microsomal oxidase, such as some fish, as this enzyme enables the rapid metabolism of certain polycyclic aromatic hydrocarbons(6). A measured fish biotransformation half-life of 2.08 days has been reported for the analogous pyrene(7). The near surface half-life for direct photolysis of analogous pyrene in water by sunlight was measured as 0.68 hours(8) and 0.85 hours(9). PAHs with four or more rings, such as 2,7-dimethylpyrene, are generally expected to be resistant to biodegradation(10). By analogy to pyrene, biodegradation is expected to occur slowly in soils, with estimated half-lives ranging from several weeks to years(11,12). Faster biodegradation rates occur with exposure to acclimated microbes(13). Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions(3).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2,7-dimethylpyrene, which has an estimated vapor pressure of 6.9X10-8 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 2,7-dimethylpyrene 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 2.4 hours(SRC), calculated from its rate constant of 1.6X10-10 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(2). Particulate-phase 2,7-dimethylpyrene may be removed from the air by wet and dry deposition(SRC). By analogy to pyrene which absorbs strongly at wavelengths >290 nm(3,4), 2,7-dimethylpyrene is expected to be susceptible to direct photolysis by sunlight(SRC).

The rate constant for the vapor-phase reaction of 2,7-dimethylpyrene with photochemically-produced hydroxyl radicals has been estimated as 1.6X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2.4 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Methylpyrenes have practically identical UV absorption spectra as pyrene(2). Pyrene (analogous compound) absorbs strongly at wavelengths >290 nm(3,4) and, therefore, 2,7-dimethylpyrene is expected to be susceptible to direct photolysis by sunlight(SRC). Approximately 6% photolytic degradation occurred when pyrene was adsorbed to a fly ash substrate and exposed to natural sunlight for 5 hours(5). The near surface half-life for direct photolysis of pyrene in water by sunlight was measured as 0.68 hours(6) and 0.85 hours(7). The photolysis half-life of pyrene on spruce needle surfaces exposed to full sunlight in Munich, Germany in July 2001 was 37 hours(8). 2,7-Dimethylpyrene is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(9).

An estimated BCF of 4400 was calculated in fish for 2,7-dimethylpyrene(SRC), using an estimated log Kow of 6.03(1) and a regression-derived equation(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is very high(SRC), provided the compound is not metabolized by the organism(SRC). However, 2,7-dimethylpyrene may not bioconcentrate in aquatic organisms which contain microsomal oxidase, such as fish, as this enzyme enables the rapid metabolism of certain polycyclic aromatic hydrocarbons(3). A measured fish biotransformation half-life of 2.08 days has been reported for the analogous compound pyrene(4).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 2,7-dimethylpyrene can be estimated to be 140,000(SRC). According to a classification scheme(2), this estimated Koc value suggests that 2,7-methylpyrene is expected to be immobile in soil.

The Henry's Law constant for 2,7-dimethylpyrene is estimated as 3.4X10-6 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This value indicates that 2,7-dimethylpyrene is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the estimated volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as approximately 17 days(SRC). The estimated 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 approximately 126 days(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 (2 m deep, 1 cm active benthic subsystem of bulk density 1.75 g/cc, wind velocity of 1.5 m/sec) is >10 years if adsorption is considered and 170 days if adsorption is ignored(3). 2,7-Dimethylpyrene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 2,7-Dimethylpyrene is not expected to volatilize from dry soil surfaces based on an estimated vapor pressure of 6.9X10-8 mm Hg(SRC), determined from a fragment constant method(1).

Occupational exposure to 2,7-dimethylpyrene may occur through inhalation and dermal contact with this compound at workplaces where 2,7-dimethylpyrene is produced as a product of incomplete combustion of fossil fuels. The general population may be exposed to 2,7-dimethylpyrene via inhalation of ambient air contaminated from combustion emissions, inhalation of tobacco smoke and dermal contact with particulate matter resulting from combustion(SRC). Occupational and general population exposure to PAHs, such as 2,7-dimethylpyrene, generally occurs as a mixture(1). PAHs, such as methylpyrenes, can occur in foods that are char-broiled(1) or smoked(2).

Immediate First Aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Aromatic hydrocarbons and related compounds/|Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). 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 pulmonary edema and treat if necessary ... . 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 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 L of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Aromatic hydrocarbons and related compounds/|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 ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start IV administration of D5W TKO /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 (Valium) or lorazepam (Ativan) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Aromatics hydrocarbons and related compounds/