Chemical Properties
Three of the listed PAHs (dibenz[a,h]acridine, dibenz[a,j]acridine, and 7H-dibenzo[c,g]carbazole) contain a nitrogen atom as part of a ring and therefore are classified as heterocyclic PAHs. The PAHs can exist as leaflets, plates, needles, or at room temperature and range in color from colorless to yellow, green or blue. All PAHs are soluble in water and slightly soluble in ethanol, acetone or acid; most are soluble in benzene. Physical and chemical properties of the 15 PAHs are listed in the table below. In addition to the properties listed in the table, benzo[a]pyrene has a specific gravity of 1.351 and a vapor density relative to air of 8.7, and dibenzo[a,h]anthracene has a specific gravity of 1.282 (HSDB 2009).
Uses
IARC (1983) reported that no commercial uses or applications were known for dibenzo[a,h]pyrene, dibenzo[a,i]pyrene, and 5-methylchrysene. The remaining twelve listed PAHs are used only in biochemical, biomedical, laboratory, or cancer research (HSDB 2009). At least five of the listed PAHs are present in coal tar, which is used as a fuel in the steel industry in open-hearth and blast furnaces (HSDB 2009). Coal tar is also used in the clinical treatment of skin disorders such as eczema, dermatitis, and psoriasis. Coal tar is distilled to produce a variety of products, including coal-tar pitch and creosote. At least two of the listed PAHs are present in coal-tar pitch, which is used primarily as a binder for aluminum smelting electrodes in the aluminum reduction process. Coal-tar pitch is also used in roofing, in surface coatings, for pitch-coke production, and for a variety of other applications (IARC 1985). At least two of the listed PAHs are found in creosote, which is used to preserve railroad ties, marine pilings, and telephone poles. Some creosote is used for fuel by steel producers (NIOSH 1977). At least three of the listed PAHs are present in bitumens and asphalt, which are used for paving roads, sound- and water-proofing, and coating pipes.
Uses
5-Methylchrysene is one of the methylated chrysenes (MeChry), as an aryl hydrocarbon receptor (AhR) agonist. Methylated chrysenes (MeChry) are important cigarette smoke constituents and 5-MeChry has been listed as possibly carcinogenic to humans. 5-Methylchrysene is a possible carcinogenic agent.
Definition
ChEBI: 5-Methylchrysene is a carbopolycyclic compound.
General Description
Purple crystals. Water insoluble.
Air & Water Reactions
Dust/air mixture may ignite and explode. Insoluble in water.
Reactivity Profile
Vigorous reactions, sometimes amounting to explosions, can result from the contact between aromatic hydrocarbons, such as 5-METHYLCHRYSENE, and strong oxidizing agents. They can react exothermically with bases and with diazo compounds. Substitution at the benzene nucleus occurs by halogenation (acid catalyst), nitration, sulfonation, and the Friedel-Crafts reaction.
Safety Profile
Confirmed carcinogen
with experimental carcinogenic,
neoplastigenic, and tumorigenic data.
Mutation data reported. When heated to
decomposition it emits acrid smoke and
irritating fumes.
Carcinogenicity
The 15 individual PAHs are reasonably anticipated to be human carcinogens
based on sufficient evidence of carcinogenicity from studies in experimental animals.
Toxics Screening Level
The initial risk screening level and secondary risk screening level (SRSL) for benzo(a)pyrene
(B(a)P) are 6E-4 μg/m3 and 6E-3 μg/m3, respectively. The IRSL and SRSL were derived from
the inhalation unit risk (IUR) factor for B(a)P of 1.76E-3 per μg/m3 (1.1E-3 per μg/m3 multiplied
by an age-dependent adjustment factor or ADAF of 1.6).
