SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 57976
CASRN 57-97-6
Synonyms7,12-Dimethylbenz(a)anthracene
7,12-Dimethyl-1,2-Benzanthracene
1,2-Benzanthracene, 7,12-dimethyl-
DMBA
Analytical Method EPA Method 8270
Molecular FormulaC20H16

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

Use IN EXPTL MEDICINE TO INDUCE VARIOUS MALIGNANT TUMORS IN TESTING ANTINEOPLASTIC DRUGS RESEARCH CHEMICAL
Consumption Patterns NOT USED COMMERCIALLY IN U.S.
Apparent Color PLATES, LEAFLETS FROM ACETONE & ALC, FAINT GREENISH-YELLOW TINGE
Melting Point 122-123 DEG C
Molecular Weight 256.33
Environmental Impact Contrary to many polynuclear aromatic hydrocarbons (PAHs) including benz(a)anthracenes, there is no evidence that 7,12-dimethylbenz(a)anthracene (DMBA) is released into the environment as a product of incomplete combustion despite innumerable PAH monitoring studies. Only two citations of its occurrence in environmental samples could be found, kale and mineral oil. The data for kale is suspect and the reference citing its occurrence in mineral oil was a secondary source in which the experimental details could not be scrutinized. If released into air or water it will be partially associated with particulate matter. In the atmosphere, DMBA will be subject to photolysis and photooxidation although no rates specifically relating to DMBA could be found in the literature. The particulate-bound compound may be transported moderate distances before settling out. In the water, it will sorb strongly to sediment and the unadsorbed DMBA in surface layers of water will photodegrade. Its slow desorption from sediment and particulate matter may maintain a low concentration of the chemical for long periods of time. Based upon physical properties, DMBA should bioconcentrate in fish. In soil, the strongly adsorbed DMBA will remain in the upper few centimeters of soil. Its fate there is unknown.
Environmental Fate TERRESTRIAL FATE: If spilled on soil, 7,12-dimethylbenzoanthracene will remain in the surface layers because it is strongly adsorbed (see also Koc). The possibility that it will slowly biodegrade in soil, as with other polynuclear aromatic hydrocarbons, has not been investigated. AQUATIC FATE: If 7,12-dimethylbenzanthracene (DMBA) is released to water, it will sorb to sediment and particulate matter in the water column. It will photodegrade, the extent of which will depend on the temperature, dissolved oxygen, and the amount of solar radiation received which is in turn a function of water depth and turbidity. The estimated half-life of the dissolved compound in natural water from the southeastern U.S. is 6 hr. The photodegradation of DMBA sorbed to particulate matter has not been investigated. There is a potential that the sorbed compound will be slowly desorbed, thereby contributing low levels of DMBA for long periods of time. ATMOSPHERIC FATE: 7,12-dimethylbenz(a)anthracene (DMBA) released to the atmosphere will exist in both the free vapor state and adsorbed to particulate matter. Although DMBA will be subject to photolysis and photooxidation, no studies could be found in the literature dealing with these processes in the free vapor or when adsorbed to particulate matter. The sorbed material will most likely be more resistant to photodegradation. As with other polynuclear aromatic hydrocabons, it may be transported moderate distances, subject to gravitational settling and scavenging by rain and snow.

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