7-Methylbenz[a]anthracene

242.314

242.31

219-819-1

F0662CQU1Q

30974

DTXSID40180072

Yellow plates from alcohol

2902909090

0

6.37

1.2±0.1 g/cm3

141 °C

449.4±12.0 °C at 760 mmHg

217.8±13.7 °C

1.748

11ug/L(24 ºC)

Keep container tightly closed in a dry and well-ventilated place.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz

3.06X10-7 mm Hg at 25 deg C (est)

Henry's Law constant = 1.90X10-6 atm-cu m/mol at 25 °C (est)

Hydroxyl radical reaction rate constant = 1.31X10-10 cu cm/molec-sec at 25 °C (est)

Stable under recommended storage conditions.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz

P264, P270, P273, P301+P312, P330, P501

H302

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.|Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber; Contaminated packaging: Dispose of as unused product.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz

Incompatible materials: Strong oxidizing agents.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz

|Warning|H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]|P264, P270, P273, P301+P312, P330, and P501|Aggregated GHS information provided by 39 companies from 2 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|H302: Harmful if swallowed [Warning Acute toxicity, oral]

Eye/face protection: Safety glasses with side-shields conforming to EN166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|Skin protection: Handle with gloves.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|Body Protection: Complete suit protecting against chemicals. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|Respiratory protection: For nuisance exposures use type P95 (US) or type P1 (EU EN 143) particle respirator. For higher level protection use type OV/AG/P99 (US) or type ABEK-P2 (EU EN 143) respirator cartridges. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|For more Personal Protective Equipment (PPE) (Complete) data for 7-Methylbenz(a)anthracene (6 total), please visit the HSDB record page.

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|Advice for firefighters: Wear self contained breathing apparatus for fire fighting if necessary.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Avoid breathing dust. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. Environmental precautions:Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|Precautions for safe handling: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed. Normal measures for preventive fire protection.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|Appropriate engineering controls: Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.[Sigma-Aldrich; Safety Data Sheet for 7-Methylbenz|For more Preventive Measures (Complete) data for 7-Methylbenz(a)anthracene (8 total), please visit the HSDB record page.

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/

7-Methylbenz(a)anthracene release sources include oil refinery emissions, gasoline exhaust and cooking emissions(1). Methylbenz(a)anthracenes, including 7-methylbenz(a)anthracene, were reported at a concentration range of 30-50 ng/mg extract in diesel engine exhaust of passenger cars(2). 7-Methylbenz(a)anthracene was detected, not quantified in boiler emissions at the coastal Powell River Pulp Mill, British Columbia, Canada; sampling conducted September, 1996(3). Methylbenz(a)anthracenes are found in airborne particulates from cigarette smoke condensate, stack gases, roofing tar extracts, and industrial effluents(4).

URBAN/SUBURBAN: Average concentrations reported for 7-methylbenz(a)anthracene in air samples from 10 roadside sites in Hanoi, Vietnam, sampled in August, 2005(1).[Table#4777]

7-Methylbenz(a)anthracene was detected in mineral oil at unreported concentrations(1).

IDENTIFICATION AND USE: 7-Methylbenz(a)anthracene (7-MBA) is a solid. It can be formed from incomplete combustion of organic materials. it is used mostly in biochemical research. HUMAN EXPOSURE AND TOXICITY: There are no data available. ANIMAL STUDIES: DNA adducts formed in mouse epidermis following topical application of 7-MBA. In other experiment, mice received sc administration of 230 ug of 7-MBA three times per week for 12 months (100 mg/single dose). Out of 35 mice, 13 had carcinomas. The 12 possible monomethylbenz[a]anthracenes (MBAs) were examined for their tumor-initiating activity in the classical two-stage initiation-promotion experiment. Based on the average number of tumors/mouse, 7-MBA was the most tumorigenic compound of the series causing 4.9 papillomas/mouse at an initiating dose of 400 nmol/mouse. When given to newborn male and female mice 7-MBA gave rise to sc sarcomata at injection site, and multiple lung tumors and liver tumors. Dihydrodiol dehydrogenase decreased the mutagenicity of 7-MBA in Salmonella typhimurium TA 100 with metabolic activation. There appeared to be little quantitative correspondence between carcinogenic and mutagenic potency in this group of chemicals.

In S. typhimurium TA98 (in presence of rat liver postmitochondrial supernatant), 1,1,1-trichloropropene 2,3-oxide, an inhibitor of epoxide hydratase, incr microsome-mediated mutagenicity of 7-methylbenz(a)anthracene.

7-Methylbenz(a)anthracene is one of many polycyclic aromatic hydrocarbons (PAH), a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances. PAHs generally occur as complex mixtures, for example as part of combustion products such as soot, not as single compounds. PAHs occur naturally in volcanoes and forest fires. They can also be found in substances such as crude oil and coal. They are found throughout the environment in the air, water, and soil(1). /Polycyclic aromatic hydrocarbons/

7-Methylbenz(a)anthracene is a product of incomplete combustion. Its presence in oil refinery emissions, gasoline exhaust and cooking emissions(1) will result in 7-methylbenz(a)anthracene's release to the environment through various waste streams(SRC). Methylbenz(a)anthracenes are found in airborne particulates from cigarette smoke condensate, stack gases, roofing tar extracts and industrial effluents(2).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 3.0X10+5(SRC), determined from a structure estimation method(2), indicates that 7-methylbenz(a)anthracene is expected to be immobile in soil(SRC). Volatilization of 7-methylbenz(a)anthracene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.9X10-6 atm-cu m/mole(SRC), using a fragment constant estimation method(3). However, adsorption to soil is expected to attenuate volatilization(SRC). 7-Methylbenz(a)anthracene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 3.1X10-7 mm Hg at 25 °C(SRC), determined from a fragment constant method(2). Biodegradation half-lives of 20 and 28 days for analogous 7,12-dimethylbenz(a)anthracene in Kidman sandy loam and McLaurin sandy loam, respectively(4), suggest that biodegradation may be an important environmental fate process in soil(SRC).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 3.0X10+5(SRC), determined from a structure estimation method(2), indicates that 7-methylbenz(a)anthracene 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 1.9X10-6 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 30 and 220 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 volatilization half-life from a model pond is about 890 years when adsorption is considered(5). According to a classification scheme(6), an estimated BCF of 4700(SRC), from an estimated log Kow of 6.07(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). Analogous 7,12-dimethylbenz(a)anthracene's slow biodegradation in water, exhibiting 12% CO2 production after 62 days(7), suggests that biodegradation is not expected to be an important fate process in water(SRC).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 7-methylbenz(a)anthracene, which has an estimated vapor pressure of 3.1X10-7 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), will exist in both the vapor and particulate phases is expected to exist solely in the particulate phase in the ambient atmosphere. Vapor-phase 7-methylbenz(a)anthracene 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 0.08 days(SRC), calculated from its rate constant of 1.3X10-10 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase 7-methylbenz(a)anthracene may be removed from the air by wet and dry deposition(SRC). Analogous anthracene contains chromophores that absorb at wavelengths >290 nm(4), suggesting that 7-methylbenz(a)anthracene may be susceptible to direct photolysis by sunlight(SRC).

The rate constant for the vapor-phase reaction of 7-methylbenz(a)anthracene with photochemically-produced hydroxyl radicals has been estimated as 1.3X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 0.08 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 7-Methylbenz(a)anthracene is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). Analogous anthracene contains chromophores that absorb at wavelengths >290 nm(2), suggesting that 7-methylbenz(a)anthracene may be susceptible to direct photolysis by sunlight(SRC).

An estimated BCF of 4700 was calculated in fish for 7-methylbenz(a)anthracene(SRC), using an estimated log Kow of 6.07(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, provided the compound is not metabolized by the organism(SRC). However, bioconcentration studies on compounds which are structurally similar suggest that bioconcentration may be lower than that indicated by the regression-derived equations due to the ability of some aquatic organisms to readily metabolize this class of compounds(3).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 7-methylbenz(a)anthracene can be estimated to be 3.0X10+5(SRC). According to a classification scheme(2), this estimated Koc value suggests that 7-methylbenz(a)anthracene is expected to be immobile in soil.

The Henry's Law constant for 7-methylbenz(a)anthracene is estimated as 1.9X10-6 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 7-methylbenz(a)anthracene 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 30 days(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 220 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 about 890 years when adsorption is considered(3). 7-Methylbenz(a)anthracene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 7-Methylbenz(a)anthracene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 3.1X10-7 mm Hg(SRC), determined from a fragment constant method(4).

Occupational exposure to 7-methylbenz(a)anthracene may occur through inhalation of dust particles contaminated with incomplete combustion products and dermal contact with incomplete combustion products containing 7-methylbenz(a)anthracene. Limited monitoring data indicate that the general population may be exposed to 7-methylbenz(a)anthracene via inhalation of ambient air. (SRC)

Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included. (See all compounds classified as Carcinogens.)

The fungal metabolism of 7-methylbenz[a]anthracene (7-MBA) and 7-hydroxymethylbenz[a]anthracene (7-OHMBA) was studied. 7-MBA was metabolized by Cunninghamella elegans to form 7-OHMBA-trans-8,9-dihydrodiol and 7-OHMBA-trans-3,4-dihydrodiol as the predominant metabolites. Other metabolites were identified as 7-OHMBA, 7-MBA-trans-8,9-dihydrodiol and 7-MBA-trans-3,4-dihydrodiol, and 7-MBA-8,9,10,11-tetraol. Incubation of 7-OHMBA with C. elegans cells indicated that 7-OHMBA-trans-8,9-dihydrodiol and 7-OHMBA-trans-3,4-dihydrodiol were major metabolites. The metabolism of 7-MBA by rat liver microsomes from 3-methylcholanthrene-treated rats showed that the metabolites were qualitatively similar to those formed by C. elegans, except additional dihydrodiol metabolites were formed at the 5,6 and 10,11 positions. The metabolites formed were isolated by high-performance liquid chromatography and identified by comparing their chromatographic, UV-visible absorption and mass spectral properties with those of reference compounds.|7-Methylbenz[a]anthracene (7-MBA) was metabolized stereoselectively by rat liver microsomes to form five optically active dihydrodiols as the predominant metabolites. The dihydrodiols were purified by a combination of reversed-phase and normal-phase high performance liquid chromatography (HPLC). By comparison of their circular dichroism (CD) spectra with the corresponding benz[a]anthracene (BA) dihydrodiols of known absolute stereochemistry, the major dihydrodiol enantiomers of 7-MBA have been determined to have 1R,2R-, 3R,4R- and 10R , 11R - absolute configurations, respectively. Due to their quasi- diaxial conformations, the absolute configuration of trans-5,6- and trans-8,9-dihydrodiols, the two most abundant metabolites of 7-MBA, could not be determined by simple comparisons of their circular dichroism spectra with those of the quasidi -equatorial BA 5R, 6R - and 8R , 9R -dihydrodiols. The major enantiomers of the quasi- diaxial trans-5,6- and trans-8,9-dihydrodiol metabolites of 7-MBA were determined by comparison to the CD spectrum of 7-bromo-BA 5R, 6R -dihydrodiol and by the exciton chirality method to have R,R absolute stereochemistry. This study also revealed that the circular dichroism Cotton effects of an enantiomeric dihydrodiol of polycyclic aromatic hydrocarbons can be drastically altered if the conformation (quasi- diaxial vs. quasi di-equatorial ) of the dihydrodiol is changed.|The metabolism of 7-ethyl (7-EBA) and 7-methylbenz[a]anthracene (7-MBA) to dihydrodiols has been compared in incubations with hepatic microsomal fractions prepared from untreated rats. Although both hydrocarbons were found to be metabolized to similar extents, the relative proportions of their diols that were detected differed. For 7-MBA, the principal diols identified were the 8,9- and 5,6-derivatives, whereas for 7-EBA the 8,9- and 1,2-diols predominated; the 5,6-diol was only present as a minor product. These results imply that the presence of the sterically bulky ethyl group at position seven in the benz[a]anthracene ring system may, when compared to the analogous methyl derivative, enhance diol formation on the angular 1,2,3,4 benzo-ring, at the expense of metabolism at the K-region.|The carcinogen 7-methylbenz[a]anthracene (7-MBA) is considered to be metabolically activated via its bay-region dihydrodiol-epoxide, trans-3,4-dihydro-3,4-dihydroxy-7-methyl-benz[a]anthracene 1,2-oxide (7-MBA-3,4-diol 1,2-oxide). When tested on mouse skin, a target tissue for polycylic aromatic hydrocarbon carcinogenesis, 7-ethylbenz[a]anthracene (7-EBA) was much less active than 7-MBA, and this difference may be due to differences in the pathways by which the two compounds are metabolized and activated. In the present work, the metabolism by mouse-skin microsomes of both hydrocarbons to dihydrodiols has been examined. Both were metabolized to a similar extent with the 8,9-dihydrodiols being detected as the predominant metabolites. The 3,4-, 5,6-and 10,11-dihydrodiols of 7-MBA and the 3,4- and 10, 11-dihydrodiols of 7-EBA, were also detected. 7-MBA was found to bind covalently to microsomal protein at 10 times the level of 7-EBA. The covalent binding of benz[a]anthracene (BA), 7-EBA and 7-MBA to DNA in mouse skin following topical application was determined using the 32P-postlabelling assay. The results correlated with the relative carcinogenic activities of the compounds with 7-MBA binding at five and nine times the level of 7-EBA and BA respectively. For all three hydrocarbons, the major hydrocarbon: 32P-labelled nucleoside bisphosphate, eluted in the same area of the TLC maps, suggesting the involvement of a common type of bay-region dihydrodiol-epoxide intermediate.|For more Metabolism/Metabolites (Complete) data for 7-Methylbenz(a)anthracene (13 total), please visit the HSDB record page.

0.89 Days

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/

7-methylbenz(a)anthracene

FORMED FROM INCOMPLETE COMBUSTION OF ORGANIC MATERIALS (EG, REFUSE BURNING, OPERATION OF MOTOR VEHICLES, INDUST PROCESSES)