SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 53703
CASRN 53-70-3
SynonymsDibenzo(a,h)anthracene
Dibenz(a,h)anthracene
1,2:5,6-Dibenzanthracene
Analytical Methods EPA Method 525.2
EPA Method 610
EPA Method 625
EPA Method 8100
EPA Method 8270
EPA Method 8310
Molecular FormulaC22H14

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use RESEARCH CHEMICAL No known use of this compound
Apparent Color COLORLESS PLATES OR LEAFLETS RECRYSTALLIZED FROM ACETIC ACID; SOLN IN CONCENTRATED SULFURIC ACID IS RED; CRYSTALS MAY BE MONOCLINIC OR ORTHORHOMBIC
Melting Point 266 DEG C
Molecular Weight 278.33
Density 1.282
Environmental Impact Dibenz(a,h)anthracene's (DBahA) release to the environment is quite general since it is a ubiquitous product of incomplete combustion. It is largely associated with particulate matter, 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. If it is released to soils it will be expected to adsorb very strongly to the soils and will not be expected to leach to the groundwater, hydrolyze or evaporate from soils or surfaces. It will be subject to biodegradation in soils with reported half-lives of 18 and 21 days. If DBahA is released to water it will be expected to adsorb very strongly to sediments and particulate matter and to bioconcentrate in aquatic organisms which lack microsomal oxidase (this enzyme enables the rapid metabolism of certain polycyclic aromatic hydrocarbons). Based on limited data from laboratory screening tests using settled domestic wastewater and activated sludge, DBahA may be subject to biodegradation in natural waters. Since DBahA absorbs solar radiation strongly, it may be subject to direct photolysis in natural waters. However, adsorption may significantly retard photolysis as the photosensitivity of polyaromatic hydrocarbons is strongly dependent upon the nature of the surface upon which the compound is adsorbed. It will not hydrolyze and should not evaporate from water. If released to the atmosphere it will likely be associated with particulate matter and may be subject 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. Its presence in areas remote from primary sources demonstrates the potential for this long range transport as well as DBahA's considerable stability in the air. It may be subject to direct photolysis in the atmosphere; however, adsorption may significantly retard photolysis as the photosensitivity of polyaromatic hydrocarbons is strongly dependent upon the nature of the surface upon which the compound is adsorbed. The estimated vapor phase half-life in the atmosphere is 1.00 day as a result of reaction with photochemically produced hydroxyl radicals. Human exposure will be from inhalation of contaminated air and consumption of contaminated food and water.
Environmental Fate TERRESTRIAL FATE: If dibenz(a,h)anthracene is released to the soil, it will adsorb very strongly to the soil and will not be expected to leach to the groundwater. It will not hydrolyze or evaporate from soils or surfaces. It will be subject to biodegradation in soil systems with reported half-lives of 18 and 21 days . AQUATIC FATE: If dibenz(A,H)anthracene (DBahA) is released to water, it will be expected to adsorb very strongly to sediments and particulate matter. It will not hydrolyze and volatilization will not be an important process. It will be expected to bioconcentrate in aquatic organisms which lack microsomal oxidase (this enzyme enables the rapid metabolism of certain polycyclic aromatic hydrocarbons). No information was found on the biodegradation of DBahA in natural waters; however, based on limited data from laboratory screening tests using settled domestic wastewater and activated sludge, it may be subject to biodegradation in natural waters. Since DBahA's absorbs solar radiation strongly, it may be subject to direct photolysis in natural waters; however, the photosensitivity of polyaromatic hydrocarbons is strongly dependent upon the nature of the surface upon which the compound is adsorbed. ATMOSPHERIC FATE: Dibenz(a,h)anthracene (DBahA) released to the atmosphere will likely be associated with particulate matter and may be subject to moderately long range transport, depending mainly on the particle size distribution and climactic conditions which will determine the rates of wet and dry deposition. Its presence in areas remote from primary sources demonstrates the potential for this long range transport as well as DBahA's considerable stability in the air. The estimated vapor phase half-life in the atmosphere is 1.00 day as a result of reaction with photochemically produced hydroxyl radicals.
Drinking Water Impact DRINKING WATER: Identified, not quantified, in finished drinking water . EFFL: USA Nationwide Urban Runoff Program, not detected in 86 samples from 15 cities . Coal coking wastewaters, plant A (plant B) final effluent from biological oxidation process discharged to river, 0.062-0.23 ppb (0.017- 0.08 ppb), suspended solid, 2.0-2.9 ppb (0.06-0.5 ppb) . Gasoline engine exhaust, 96 ug/g, coke oven, 84-124 ug/g sample . Combined o-Phenylene pyrene and dibenz(a,c and/or a,h)anthracene: effluent channel from a coking plant, water, 0.95 ppb, sediment, 8.6 ppm dry wt .

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