6-Nitrobenzo[a]pyrene

297.31

297.31

U2BFP66YG1

DTXSID4075083

Orange-yellow needles, recrystallzed from benzene; yellow crystalline solid; orange crystals

2904209090

45.8

5.44

1.429g/cm3

252-254 °C

524.1ºC at 760 mmHg

259.5ºC

1.901

Limited solubility in toluene and benzene

2-8°C

1.0X10-10 mm Hg at 25 deg C (est)

Henry's Law constant = 3.2X10-9 atm-cu m/mol at 25 °C (est)

Reacts with chromic acid in acetic acid to form 7-oxo-7 H-benz(de)-anthracene dicarboxylic acid-3,4-anhydride.|Hydroxyl radical reaction rate constant = 6.2X10-12 cu cm/molec-sec at 25 °C (est)

P201, P202, P281, P308+P313, P405, P501

H341

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. 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 soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

|Warning|H341 (100%): Suspected of causing genetic defects [Warning Germ cell mutagenicity]|P201, P202, P281, P308+P313, P405, and P501|Aggregated GHS information provided by 12 companies from 1 notifications to the ECHA C&L Inventory.

6-Nitrobenzo[a]pyrene was emitted in the exhaust from a modern day EURO IV heavy duty diesel engine as a result of formation of 6-nitrobenzo[a]pyrene by nitration of pre-existing PAH(1). 6-Nitrobenzo[a]pyrene was detected in the particulate material emitted from the exhaust of 1978 Volkswagen Rabit diesel engine(2). 6-Nitrobenzo[a]pyrene has been detected in diesel soot (14 mg/kg), diesel-powered car exhaust particulates (50 mg/kg) and gasoline-powered car emissions (0.21-32.8 mg/kg)(3). The rates of emission of 6-Nitrobenzo[a]pyrene in automobile exhaust have been reported to be 1.46 ug/mile for a gasoline-powered car with a precatalyst engine running on leaded fuel, 0.45 ug/mile for an engine with the catalyst removed running on unleaded fuel and 0.012 ug/mile for a gasoline-powered engine with a catalytic converter(4). A production model diesel engine emitted <0.15 ug/mile and a diesel trap model, 0.01 ug/mile(4). 6-Nitrobenzo[a]pyrene has been detected in stack gases from aluminium smelters(4). A fireplace in which red oak was burned yielded emissions of 0.11 and 0.12 mg/kg particles(4).

SEDIMENT: Coastal sediments collected offshore from Barcelona, Spain, contained 6-nitrobenzo[a]pyrene concentrations of 0.34 g/kg dry weight in sediment from urban littoral stations(1).

URBAN/SUBURBAN: 6-Nitrobenzo[a]pyrene was detected in airborne particulate matter collected in Newark, NJ during Jan 1985 to Feb 1986 monitoring at concentrations ranging from 13 to 6400 pg/cu m(1). 6-Nitrobenzo[a]pyrene was identified in 2 of 17 urban aerosol samples collected in New Jersey, but was not identified in 5 rural aerosol samples at a detection limit of 1 pg/cu m(2). Air samples collected in downtown Baltimore MD in January and July 2001 contained mean 6-nitrobenzo[a]pyrene concentrations of 1.7 (range of 0.01-3.8) and 1.4 (range of 0.4-2.8) pg/cu m respectively(3); air samples collected in suburban Fort Meade MD in January and July 2001 contained mean 6-nitrobenzo[a]pyrene concentrations of 4.1 (range of 3.8-4.4) and 0.26 (range of 0.13-0.40) pg/cu m respectively(3); 100% of the 6-nitrobenzo[a]pyrene was detected in particulate material with 0% detected in the gas-phase(3). 6-Nitrobenzo[a]pyrene has been detected in airborne particles in Prague, Czechoslovakia(4). Ambient particles collected in the area of Detroit, MI during the spring and summer of 1981 contained levels of 0.9-2.5 mg/kg, corresponding to airborne concentrations of 0.04-0.28 ng/cu m(4). Air monitoring at a traffic site in the summer of 2010 and at suburban site in the summer of 2009 in Paris France, detected 6-nitrobenzo[a]pyrene in particulates samples(5); at the suburban site, 100% of 6-nitrobenzo[a]pyrene occurred in particulates <2.5 um in size(5); at the traffic site, about 70% of 6-nitrobenzo[a]pyrene occurred in particulates <2.5 um in size(5).|RURAL/REMOTE: Gaseous and pariculate samples collected in late autumn of 2010 from Wanqingsha, a rural site in the Pearl River Delta region, China, contained an average 6-nitrobenzo[a]pyrene concentration of 63 pg/cu m in the particule samples and 0 pg/cu m in the gaseous samples(1). 6-Nitrobenzo[a]pyrene was detected in air samples collected in two French alpine valleys(2).

Toners for photocopy machines prior to 1980 contained total nitropyrene levels (which include 6-nitrobenzo[a]pyrene) of 5-100 mg/kg to below 0.3 mg/k(1); due to changes in production techniques after 1980, toners had no detectable levels(1).

6-Nitrobenzo[a]pyrene's limited production and use in laboratory applications(1) may result in its release to the environment through various waste streams. 6-Nitrobenzo[a]pyrene and other nitrated-polycyclic aromatic hydrocarbons (nitro-PAHs) may be present in the atmosphere due to direct emission from sources such as diesel and gasoline exhaust and through atmospheric reaction of parent PAHs with nitrogen oxides and nitrate radicals(2). Nitro-PAHs are formed through incomplete combustion of fossil fuels like coal and oil and through pyrolysis of organic materials and may be emitted from cars, factories and oil and coal stoves(3). 6-Nitrobenzo[a]pyrene is emitted in the exhaust of modern day EURO IV heavy duty diesel engines via formation of 6-nitrobenzo[a]pyrene by nitration of pre-existing PAH(4). In laboratory chamber studies conducted at room temperatures and atmospheric pressure, 1-, 3- and 6-nitrobenzo[a]pyrene were identified as reaction products of benzo[a]pyrene exposed to NO2, NO3/N2O5 and OH radicals(5).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 9.5X10+5(SRC), determined from a structure estimation method(2), indicates that 6-nitrobenzo[a]pyrene is expected to be immobile in soil(SRC). Volatilization of 6-nitrobenzo[a]pyrene from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.2X10-9 atm-cu m/mole(SRC), using a fragment constant estimation method(2). 6-Nitrobenzo[a]pyrene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.0X10-10 mm Hg at 25 °C(SRC), determined from a fragment constant method(2). 6-Nitrobenzo[a]pyrene is susceptible to direct photolysis in sunlight(3-5) and, therefore, photodegradation may be an important fate process on soil surfaces exposed to sunlight(SRC). Nitro-substituted PAHs are only slowly degraded by indigenous microorganisms and may persist in soils and sediments(3); the recalcitrance of high molecular weight nitro-PAHs is due in part to the strong adsorption to soil organic matter, low solubility, large molecular size and the polar character of the nitro group(3).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 9.5X10+5(SRC), determined from a structure estimation method(2), indicates that 6-nitrobenzo[a]pyrene is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 3.2X10-9 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). According to a classification scheme(4), an estimated BCF of 1800(SRC), from its log Kow of 5.44(5) 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). 6-Nitrobenzo[a]pyrene is susceptible to direct photolysis in sunlight(6-8) and, therefore, photodegradation may be an important fate process in waters exposed to sunlight(SRC). Nitro-substituted PAHs are only slowly degraded by indigenous microorganisms and may persist in sediments(6); the recalcitrance of high molecular weight nitro-PAHs is due in part to the strong adsorption to sediment, low solubility, large molecular size and the polar character of the nitro group(6). 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), 6-nitrobenzo[a]pyrene, which has an estimated vapor pressure of 1.0X10-10 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Two atmospheric monitoring studies that looked for 6-nitrobenzo[a]pyrene in both the gas and particulate phases detected it only in the particulate phase(3,4). 6-Nitrobenzo[a]pyrene is susceptible to direct photolysis in sunlight(5-7). When adsorbed onto various substrates (such as alumina, silica, cellulose, diesel soots), 6-nitrobenzo[a]pyrene can photodegrade rapidly when exposed to solar irradiation(5,7). In chamber studies, 6-nitrobenzo[a]pyrene adsorbed on fresh airborne diesel and diesel soot particles degraded very rapidly in sunlight with a half-life of 30 minutes(5); however, nitro-PAHs adsorbed on aerosolized diesel soot and coal fly ash were resistant to photodegradation in sunlight(5). This suggests that the rate of photodegradation in the atmosphere may depend upon the nature of the 6-nitrobenzo[a]pyrene particulate material(SRC). Particulate-phase 6-nitrobenzo[a]pyrene may be removed from the air by wet and dry deposition(SRC).

The rate constant for the vapor-phase reaction of 6-nitrobenzo[a]pyrene with photochemically-produced hydroxyl radicals has been estimated as 6.2X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2.6 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 6-Nitrobenzo[a]pyrene contains chromophores, such as benzo[a]pyrene, that absorb strongly at wavelengths >290 nm(2) and, therefore, is susceptible to direct photolysis by sunlight(SRC). In dimethyl sulfoxide solution, 6-nitrobenzo[a]pyrene degraded by approximately 5% when irradiated with UV-light at 312 nm for 6 hours(3). Smog chamber experiments demonstrated that 6-nitrobenzo[a]pyrene degraded much more rapidly when irradiated with wavelengths >290 nm as compared to dark controls(4). Irradiation of acetonitrile solutions of 6-nitrobenzo[a]pyrene with a sunlamp resulted in >90% photodegradation after 150 minutes(5). When adsorbed to silica, alumina and cellulose surfaces, irradiation of 6-nitrobenzo[a]pyrene with a sunlamp resulted in 33.2-74.6% photodegradation after 24 hours of exposure(5). Photolabile 6-nitrobenzo[a]pyrene released nitric oxide under visible-light irradiation with the concomitant formation of the 6-oxyBaP radical(6); BaP quinones were also detected as further oxidized products of the 6-oxyBaP radical(6). 6-Nitrobenzo[a]pyrene on silica gel photolyzes rapidly to BaP quinones (1,6-, 3,6- and 6,12-isomers)(7). In chamber studies, 6-nitrobenzo[a]pyrene adsorbed on fresh airborne diesel and diesel soot particles degraded very rapidly in sunlight with a half-life of 30 minutes(7); nitro-PAHs adsorbed on aerosolized diesel soot and coal fly ash were resistant to photodegradation in sunlight(7). UVA solar irradiation of 1-, 3- and 6-nitrobenzo[a]pyrene in the presence of a lipid resulted in formation of lipid hydroperoxide(8). 6-Nitrobenzo[a]pyrene is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2).

An estimated BCF of 1800 was calculated in fish for 6-nitrobenzo[a]pyrene(SRC), using a log Kow of 5.44(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is very high(SRC), provided the compound is not metabolized by the organism(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 6-nitrobenzo[a]pyrene can be estimated to be 9.5X10+5(SRC). According to a classification scheme(2), this estimated Koc value suggests that 6-nitrobenzo[a]pyrene is expected to be immobile in soil.

The Henry's Law constant for 6-nitrobenzo[a]pyrene is estimated as 3.2X10-9 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 6-nitrobenzo[a]pyrene is expected to be essentially nonvolatile from water surfaces(2). 6-Nitrobenzo[a]pyrene's Henry's Law constant indicates that volatilization from moist soil surfaces is not expected to occur(SRC). 6-Nitrobenzo[a]pyrene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.0X10-10 mm Hg(SRC), determined from a fragment constant method(1).

Occupational exposure to 6-nitrobenzo[a]pyrene may occur through inhalation of particulates and dermal contact with this compound at workplaces where exposure to exhaust from diesel engines, industrial stack emissions or emissions from other combustion sources occur(SRC). Monitoring data indicate that the general population may be exposed to 6-nitrobenzo[a]pyrene via inhalation of ambient air. (SRC)

Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes. (See all compounds classified as Mutagens.)|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 compounds 1-, 3-, and 6-nitrobenzo[a]pyrene (nitro-BaP) are environmental pollutants and have been shown to be potent bacterial mutagens. The anaerobic metabolism of these isomeric nitro-BaPs was investigated by the incubation of rat intestinal microflora with each isomer for 48 hr. Aliquots were removed at several time intervals, extracted, fractionated by high-pressure liquid chromatography (HPLC), and the radioactivity determined. Metabolites were identified by comparison of their chromatographic, ultraviolet-visible absorption, and mass spectral properties with those of authentic standards. The order of the extent of nitroreduction for these isomers was 3-nitro-BaP greater than 6-nitro-BaP greater than 1-nitro-BaP. After 48 hr of exposure, 84% of the added 3-nitro-BaP was present as 3-amino-BaP, 51% of the 6-nitro-BaP was metabolized to 6-amino-BaP, and 1-nitro-BaP was reduced to 1-amino-BaP (13%) and 1-nitroso-BaP (4%). The order of the extent of microbial nitroreduction for these nitro-BaP isomers is different from the predictions based on electronic and steric hindrance effects. These results suggest that intestinal microflora nitroreductases exhibit a markedly high degree of substrate specificity toward nitro-BaPs that affects the extent of nitroreduction.

Ionization potential (IP), electron affinity (EA), dipole moment (mu) and electronic polarizability (alpha) of 1-, 3- and 6-nitrobenzo[a]pyrene isomers (1-NBaP, 3-NBaP, 6-NBaP) were determined by using density functional theory (DFT) and recent semiempirical PM6 methods. Calculated IP value remains almost constant along the series of isomers, while EA value depends on the nitro group position, increasing by ca. 0.2 eV on passing from 6- to 1-NBaP (or 3-NBaP) isomer. Stability, mu and alpha values decrease in the order 6-NBaP < 1-NBa approximately 3-NBaP, the largest mu variation being predicted to be 1.5 D (30%) by DFT computations. The results obtained herein are consistent with the observed greater mutagenic activity of 3- and 1-NBaP in comparison to 6-NBaP isomer, suggesting that both binding to enzyme, which depends on electric properties, and reduction process, which is related to EA value may be crucial steps in the mutagenic mechanism of this series of isomers.

/SRP:/ 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 the 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. /Poisons A and B/|/SRP:/ 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 needed. 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 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/|/SRP:/ 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 as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's 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 ... . /Poisons A and B/

/GENOTOXICITY/ Metabolism of 6-nitrobenzo[a]pyrene led to DNA adduct formation in ...explanted human tissues and animals. 6-Nitrobenzo[a]pyrene caused transformation of ...human cultured cells...|/OTHER TOXICITY INFORMATION/ Questionable carcinogen.

6-nitrobenzo(a)pyrene

6-Nitrobenzo(a)pyrene is available at a certified purity of 99.75%. It is also available at greater than or equal to 99% purity and at greater than or equal to 98% radiochemical purity as the (3)H-labelled compound.

6-Nitrobenzo[a]pyrene has been detected in stack gases from aluminium smelters and in particulate emissions from diesel and gasoline engines. It has also been measured at low concentrations in ambient air.

Nitroarenes have been analyzed by HPLC, gas chromatography and mass spectrometry; some thin-layer chromatography methods have been described. /Nitroarenes/