Бензо [а] пирен

Описание

Benzo(a)pyrene (BaP) is bioactivated to its carcinogenic form by phase 1 and phase 2 metabolism. As with other polycyclic aromatic hydrocarbons (PAHs), the presence of the ‘bay region’ contributes greatly to the carcinogenicity of BaP. This region is sterically constrained, allowing the formation of diol epoxides, which subsequently react with intracellular molecules such as DNA. Human exposure to BaP and other PAHs occurs primarily from smoking or from secondhand smoke, air polluted with combustion products, or food and water polluted with combustion products, such as those cooked over charcoal or broiled.
BaP has been extensively studied for its toxicities in children and during pregnancy. A study of pregnant active smokers showed that BaP crossed the human placenta and was bound to fetal hemoglobin at levels significantly higher than in pregnant nonsmokers.

Химические свойства

B(a)P, is yellowish needles, crystals or powder. Odorless. PAHs are compounds containing multiple benzene rings and are also called polynuclear aromatic hydrocarbons.

Физические свойства

Odorless, yellow, orthorhombic or monoclinic crystals from ethanol. Solution in concentrated sulfuric acid is orange-red and fluoresces green under exposure to UV light (quoted, Keith and Walters, 1992).

Использование

Benzopyrene is a polyaromatic hydrocarbon (PAH) found in coal tar. Benzopyrene is a known carcinogen. The metbolism of Benzopyrene results in diol epoxides that react and bind to DNA forming adducts which in turns leads to mutations and eventually cancer.

Определение

ChEBI: An ortho- and peri-fused polycyclic arene consisting of five fused benzene rings.

Общее описание

A liquid. Presents a threat to the environment. Immediate steps should be taken to limits its spread to the environment. Easily penetrates the soil and contaminates groundwater or nearby waterways.

Реакции воздуха и воды

Insoluble in water.

Профиль реактивности

BENZO[A]PYRENE undergoes photo-oxidation after irradiation in indoor sunlight or by fluorescent light in organic solvents. Incompatible with strong oxidizing agents including various electrophiles, peroxides, nitrogen oxides and sulfur oxides. Oxidized by ozone, chromic acid and chlorinating agents. Readily undergoes nitration and halogenation. Hydrogenation occurs with platinum oxide .

Опасность

Highly toxic, confirmed carcinogen by inhalation.

Угроза здоровью

The acute oral toxicity of benzo[a]pyrene islow. This may be due to the poor absorption of this compound by the gastrointestinal tract.The lethal dose in mice from intraperitonealadministration is reported as 500 mg/kg(NIOSH 1986).
Animal studies show sufficient evidence ofits carcinogenicity by all routes of exposureaffecting a variety of tissues, which includethe lungs, skin, liver, kidney, and blood.
Dasenbrock et al. (1996) have investigatedthe carcinogenic potency of carbon particles,diesel soot and benzo[a]pyrene in rats fromrepeated intracheal administration in a 16-week study. A total dose of 15 mg purebenzo[a]pyrene caused lung tumor in theexperimental animals at a rate similar tothat caused by diesel soot and carbon blackparticles.
Lodovici et al. (1998) measured the levelsof PAHs and benzo[a]pyrenediol epoxideDNA adduct in autoptic lung samples ofsmokers and non-smokers. Benzo[a]pyrenediol epoxide resulting from metabolic activation of benzo[a]pyrene binds to DNA to forman adduct, the levels of which can be used as abiomarker to evaluate the exposure of humansto benzo(a)pyrene.
Benz[a]pyrene exhibited teratogeniceffects in test species. It is a mutagen.It showed positive in a histidine rever-sion–Ames test, cell transform mouse embryotest, and in in vitro sister chromatid exchange(SCE)–human lymphocytes..

Пожароопасность

Literature sources indicate that BENZO[A]PYRENE is nonflammable.

Токсикология

benzo[a]pyrene (BP) is a reasonably potent contact carcinogen, and therefore has been subjected to extensive carcinogenic testing. A diet containing 25 ppm of benzo[a]pyrene (BP) fed to mice for 140 days produced leukemia and lung adenomas in addition to stomach tumors. Skin tumors developed in over 60% of the rats treated topically with approximately 10 mg of benzo[a]pyrene three times per week. The incidence of skin tumors dropped to about 20% when treatment was about 3 mg  3 per week. Above the 10 mg range, however, the incidence of skin tumors increased dramatically to nearly 100%. benzo[a]pyrene (BP) is also carcinogenic when administered orally. In one experiment, weekly doses of greater than 10 mg administered for 10 weeks induced stomach cancers, although no stomach cancers were produced at the dose of 10 mg or less. At 100 mg doses, nearly 79% of the animals had developed stomach tumors by the completion of the experiment. When 15 ppm of benzo[a]pyrene (BP) in feed was orally administered to mice, production of leukemia, lung adenomas, and stomach tumors were observed after 140 days.

Профиль безопасности

Confirmed carcinogen withexperimental carcinogenic, neoplastigenic, andtumorigenic data. A poison via subcutaneous,intraperitoneal, and intrarenal routes. Experimentalteratogenic and reproductive effects. Human mutation data reported. A skin irritant.

Возможный контакт

Benzopyrene (BP) is a PAH that has no commercial-scale production. B(a)P is produced in the United States by one chemical company and distributed by several specialty chemical companies in quantities from 100 mg to 5 g for research purposes. Although not manufactured in great quantity, B(a)P is a by-product of combustion. It is estimated that 1.8 million pounds per year are released from stationary sources, with 96% coming from: (1) coal refuse piles, outcrops, and abandoned coal mines; (2) residential external combustion of bituminous coal; (3) coke manufacture; and (4) residential external combustion of anthracite coal. Human exposure to B(a)P can occur from its presence as a by-product of chemical production. The number of persons exposed is not known. Persons working at airports in tarring operations; refuse incinerator operations; power plants, and coke manufacturers, may be exposed to higher B(a)P levels than the general population. Scientists involved in cancer research or in sampling toxic materials may also be occupationally exposed. The general population may be exposed to B(a)P from air pollution, cigarette smoke, and food sources. B(a) P has been detected in cigarette smoke at levels ranging from 0.2 to 12.2:g per 100 cigarettes. B(a)P has been detected at low levels in foods ranging from 0.1 to 50 ppb.

Экологическая судьба

The main natural sources of Benzo[a]pyrene(BaP) are forest fires and erupting volcanoes. Anthropogenic sources include the combustion of fossil fuels, coke oven emis- sions, and vehicle exhausts. In surface waters, direct deposition from the atmosphere appears to be the major source of BaP. Benzo[a]pyrene is moderately persistent in the environment. It readily binds to soils and does not readily leach to groundwater, though it has been detected in some groundwater. If released to water, it sorbs very strongly to sediments and particulate matter. In most waters and sediments, it resists breakdown by microbes or reactive chemicals, but it may evaporate or be degraded by sunlight. In water supply systems, it tends to sorb to any particulate matter and be removed by filtration before reaching the tap. In tap water, its source is mainly from PAH-containing materials in water storage and distribution systems.

Методы очистки

A solution of 250mg of benzo[a]pyrene in 100mL of *benzene is diluted with an equal volume of hexane, then passed through a column of alumina, Ca(OH)2 and Celite (3:1:1). The adsorbed material is developed with a 2:3 *benzene/hexane mixture. (It showed as an intensely fluorescent zone.) The main zone is eluted with 3:1 acetone/EtOH, and is transferred into 1:1 *benzene-hexane by adding H2O. The solution is washed, dried with Na2SO4, evaporated and crystallised from *benzene by the addition of MeOH [Lijinsky & Zechmeister J Am Chem Soc 75 5495 1953]. Alternatively it can be chromatographed on activated alumina, eluted with a cyclohexane-*benzene mixture containing up to 8% *benzene, and the solvent evaporated under reduced pressure [Cahnmann Anal Chem 27 1235 1955], and crystallised from EtOH [Nithipatikom & McGown Anal Chem 58 3145 1986]. [Beilstein 5 III 2517, 5 IV 2687.] CARCINOGENIC.

Несовместимости

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, nitrogen dioxide and ozone.

Утилизация отходов

Incineration in admixture with a flammable solvent.