53-70-3

White crystals or pale yellow solid. Sublimes.

DIBENZ[A,H]ANTHRACENE is incompatible with strong oxidizing agents. Is oxidized by chromic acid and by osmium tetraoxide .

Insoluble in water.

Dibenz(a,h)anthracene is a chemical substance formed during the incomplete burning of fossil fuel, garbage, or any organic matter and is found in smoke in general; it condenses on dust particles and is distributed into water and soil and on crops. DB(a,h)A is a PAH and is also a component of coal tar pitch, which is used in industry as a binder for electrodes, and creosote is used to preserve wood. PAHs are also found in limited amounts in bituminous materials and asphalt used in industry and for paving.

Flash point data for this chemical are not available; however, DIBENZ[A,H]ANTHRACENE is probably combustible.

Move victim to fresh air. Call 911 or emergency medical service. Give artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; give artificial respira- tion with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with run- ning water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin. Keep victim warm and quiet. Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. Medical obser- vation is recommended for 24 to 48 hours after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized para- medic may consider administering a drug or other inhala- tion therapy.

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.

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

Dibenz(a,h)anthracene is a colorless, crystal- line solid. PAHs are compounds containing multiple benzene rings and are also called polynuclear aromatic hydrocarbons.

Dibenz[a,h]anthracene is a white crystalline solid. It is insoluble in water, slightly soluble in alcohol, and soluble in ether. This compound is incompatible with strong oxidizers.

white to light yellow crystalline solid

See the entry on Coal Tar Pitch Volatiles. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/ mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal.

Colorless to pale yellow, monoclinic or orthorhombic crystals which with a faint, pleasant odor.

Dibenz[a,h]anthracene is a polycyclic aromatic hydrocarbon (PAH) and a known carcinogen. Dibenz[a,h]anthracene has produced positive results in bacterial DNA damage and mutagenicity assays and in mammalian cell DNA damage, mutagenicity and cell transformation assays.

There is no report on the common use of dibenz[a,h]anthracene and its commercial production.

ChEBI: Dibenz[a,h]anthracene is an ortho-fused polycyclic arene. It has a role as a mutagen.

There is no commercial production or known use of this compound. It has been isolated from the coal tar pitch and is found in coke over effluents. It has been detected in urban atmospheres and occurs in tobacco smoke. Dibenz [a,h]anthracene is present as a minor component of the total PAH content in the environment. Human exposure occurs through smoking, inhaling of polluted air, and by ingesting food and water containing combustion products.

The toxicity of dibenz[a,h]anthracene is onthe same order as that of benz[a]anthracene.A lethal dose in mice by intravenous routeis 10 mg/kg. There is no report on its oraltoxicity. It is a mutagen. Its carcinogenicityin animals is well established, causing cancersin the lungs, liver, kidney, and skin.

Based on no human data and sufficient data from animal assays, IRIS classifies dibenz [a,h]anthracene as a B2 carcinogen, a probable human carcinogen, and the IARC classifies dibenz[a,h]anthracene as a 2A carcinogen. Dibenz[a,h]anthracene produced carcinomas in mice following oral or dermal administration and injection site tumors in several species following s.c. or i.m. injection. It is also a tumor initiator.

Constituent in coal tar, cigarette smoke (4 μg/1,000 cigarettes), and exhaust condensate of gasoline engine (96 μg/g) (quoted, Verschueren, 1983). Also detected in asphalt fumes at an average concentration of 12.25 ng/m³ (Wang et al., 2001).
Based on laboratory analysis of 7 coal tar samples, dibenz[a,h]anthracene was not detected (EPRI, 1990). Lehmann et al. (1984) reported dibenz[a,h]anthracene concentrations of 0.03 mg/g and 1,300 mg/kg in a commercial anthracene oil and high-temperature coal tar, respectively. Identified in a high-temperature coal tar pitch used in roofing operations at concentrations ranging from 317 TO 1,680 mg/kg (Malaiyandi et al., 1982).
Nine commercially available creosote samples contained dibenz[a,h]anthracene at concentrations ranging from 1 to 16 mg/kg (Kohler et al., 2000).
Under atmospheric conditions, a low rank coal (0.5–1 mm particle size) from Spain was burned in a fluidized bed reactor at seven different temperatures (50 °C increments) beginning at 650 °C. The combustion experiment was also conducted at different amounts of excess oxygen (5 to 40%) and different flow rates (700 to 1,100 L/h). At 20% excess oxygen and a flow rate of 860 L/h, the amount of dibenz[a,h]anthracene emitted ranged from 32.0 ng/kg at 900 °C to 260.9 ng/kg at 750 °C. The greatest amount of PAHs emitted were observed at 750 °C (Mastral et al., 1999).

Biological. In activated sludge, <0.1% of the applied dibenz[a,h]anthracene mineralized to carbon dioxide after 5 d (Freitag et al., 1985). Based on aerobic soil die away test data, the estimated half-lives ranged from 361 to 940 d (Coover and Sims, 1987).
Ye et al. (1996) investigated the ability of Sphingomonas paucimobilis strain U.S. EPA 505 (a soil bacterium capable of using fluoranthene as a sole source of carbon and energy) to degrade 4, 5, and 6-ringed aromatic hydrocarbons (10 ppm). After 16 h of incubation using a resting cell suspension, only 7.8% of dibenz[a,h]anthracene had degraded. It was suggested that degradation occurred via ring cleavage resulting in the formation of polar metabolites and carbon dioxide.
Soil. The reported half-lives for dibenz[a,h]anthracene in a Kidman sandy loam and McLaurin sandy loam are 361 and 420 d, respectively (Park et al., 1990).
Photolytic. A carbon dioxide yield of 45.3% was achieved when dibenz[a,h]anthracene adsorbed on silica gel was irradiated with light (λ >290 nm) for 17 h (Freitag et al., 1985). The photooxidation half-life in the atmosphere was estimated to range from 0.428 to 4.28 h (Atkinson, 1987).
Chemical/Physical. Dibenz[a,h]anthracene will not hydrolyze because it does not contain a hydrolyzable functional group (Kollig, 1993).
At influent concentrations of 1.0, 0.1, 0.01, and 0.001 mg/L, the GAC adsorption capacities were 69, 12, 2.1, and 0.39 mg/g, respectively (Dobbs and Cohen, 1980).

Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. See the entry on “Coal TarPitch Volatiles.” A regulated, marked area should be established where this chemical is handled, used, or stored incompliance with OSHA Standard 1910.1045

The yellow-green colour (due to other pentacyclic impurities) is removed from it by crystallising from *benzene or by selective oxidation with lead tetraacetate in acetic acid [Moriconi et al. J Am Chem Soc 82 3441 1960]. [Beilstein 5 IV 2722.]

Dibenz[a,h]anthracene is largely associated with particulate matters, soils, and sediments. Its presence in places distant from primary sources indicates that it is reasonably stable in the atmosphere and capable of long-distance transport.
Dibenz[a,h]anthracene can be adsorbed very strongly if released to the soil. However, no leaching to the groundwater or hydrolization or evaporation from soils surface is expected.With half-lives of 18 and 21 days, it is generally subjected to biodegradation in soil systems. Volatilization of dibenz[a,h] anthracene from wet soil surfaces is not expected to be an important fate process based on an estimated Henry’s Law constant of 7.3×10^-8 atm-m3 mol^-1. A biodegradation halflife of 750 days at 20°C after incubation with unacclimated soil microcosms indicates that biodegradation is not an important environmental fate process in soil.
Dibenz[a,h]anthracene released to the atmosphere will likely be associated with particulate matter and may be subjected to moderately long-range transport, depending mainly on the particle size distribution and climatic conditions, which will determine the rates of wet and dry deposition. The estimated vapor pressure of 9.5×10¹⁰ mm Hg at 25°C of dibenz[a,h] anthracene indicates that this compound will exist solely in the particulate phase in the ambient atmosphere if released into air. Its presence in areas remote from primary sources demonstrates the potential for this long-range transport as well as dibenz[a,h]anthracene’s considerable stability in the air. Dibenz[a,h]anthracene absorbs solar radiation strongly, suggesting that it may be susceptible to direct photolysis in the environment. The estimated vapor phase half-life in the atmosphere is 1 day as a result of reaction with photochemically produced hydroxyl radicals.

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.