References - trdoer40219

Some PAH metabolites are carcinogenic, mutagenic, or teratogenic to

organisms. Rather than enhancing detoxification, metabolism of some

carcinogenic PAHs in induced animals could result in a higher steady-state level

of toxic products (Steggeman 1981). Although studies with various carcinogens

have demonstrated that chemicals can cause cancer in aquatic species, most

attempts to demonstrate carcinogenesis by PAHs in aquatic species have

produced equivocal results (Pliss and Khudoley 1975). Although recently there

has been some evidence that PAHs can cause cancer in aquatic animals, there is

to date no direct evidence of a single specific PAH induction of carcinogenesis

in aquatic species (Neff 1979 and Steggeman 1981).

Studies in the Duwamish River, Boston Harbor, and Hudson River have

identified populations of Dover sole and Atlantic tomcod with very high

incidences of hepatocellular carcinoma (Varanasi 1989), and higher incidences

of similar diseases have been reported for other environments. Although the

etiology of such diseases in fish is uncertain, there is reason to suspect that the

chemical environment is responsible, and PAHs have not been exonerated

(Steggeman 1981). Bottom sediments in the areas that these fish populations

inhabited contained elevated levels of PAHs.

The impacts of concern in the terrestrial environment include both direct

toxicity and food-chain impacts. The toxic effects of PAHs in mammals can be

inferred from the extensive toxicity testing work performed on laboratory

animals. As with humans, the basic conclusion is that exposure to PAHs are only

slightly to moderately toxic by acute exposure, but longer exposures to certain

PAHs can result in cancer. Biomagnification in animal food chains is unlikely,

however, since PAHs are readily metabolized.

References

Lu, P. Y., Metcals, R. L., Plummer, N., and Mandel, D. (1987). Arch. Env.

Contam. Toxicol. 6:129-142.

Neff, J. M. (1979). Polycyclic aromatic hydrocarbons in the aquatic

environment. Applied Science Publishers, London.

Pliss, G. B., and Khudoley, V. V. (1975). J. Natl. Cancer Inst. 55:129.

Steggeman, J. J. (1981). "PAHs and their metabolism in the marine

environment." PAHs and Cancer. Vol 3, H.V. Gelboin and P. Tso, ed.

Academic Press, NY, 1-60.

U.S. Environmental Protection Agency. (1982). "An exposure and risk

assessment for benzo(a)pyrene and other polycyclic aromatic hydrocarbons,"

Volume IV, Final draft report, Washington, DC.

Varanasi, U. (1989). Metabolism of polycyclic aromatic hydrocarbons in the

aquatic environment. CRC Press, Cleveland, OH.

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Appendix D Toxicological Profiles