Phenanthrene Cas No. 85-01-8

Phenanthrene

Cas No. 85-01-8

Potential sources and exposures

Phenanthrene is a polycyclic aromatic hydrocarbon (PAH). The reader should

refer to the general profile on PAHs for exposure information.

Physical and chemical properties

Value

Property

Molecular weight

178.2 g/mol

Water solubility

1.00 mg/L at 21 C

6.8 10-4 atm at 25 C

Vapor pressure

Koc

14,000 mL/g

log Kow

4.46

1.59 10-4 atm-m3/mol at 25 oC

Henry's Law Constant

Toxicity

There are no data on the toxicity of phenanthrene to humans (IARC 1983).

Phenanthrene has been tested for carcinogenicity in laboratory animals by the

oral, dermal, and subcutaneous routes of administration (as cited in IARC 1983);

however, IARC (1983) and USEPA (IRIS 1992) concluded that data from

available studies were inadequate to permit an evaluation of its carcinogenicity

of phenanthrene. In addition, the results of short-term mutagenicity tests are

equivocal. Nonetheless, current theories regarding the mechanisms of metabolic

activation of PAHs predict that phenanthrene may have carcinogenic potential

(IRIS 1992).

Toxicokinetics

In general, many polycyclic aromatic hydrocarbon can produce toxicity after

inhalation, oral, or dermal exposure. Thus, it is believed that PAHs are absorbed

after exposure by these routes. Because of their high lipid solubility, PAHs are

believed to be distributed throughout the body. Relative to other tissues, they

tend to localize in body fat and fatty tissues. PAHs are generally metabolized by

the microsomal mixed function oxidase system and eliminated via the

hepatobiliary tract.

Several metabolites of phenanthrene have been identified. They include the

1,2- 3,4- and 9,10-dihydrodiols, and the 1,2-diol-3,4-epoxide. The dihydrodiols

displayed little or no tumor-initiating activity on mouse skin (IARC 1983). The

epoxide was found to be mutagenic in bacterial and mammalian cells (IARC

1983). USEPA (1982) reported significant tumorigenic activity with the

expoxide but not with phenanthrene itself in newborn mice.

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Appendix D Toxicological Profiles