7085

• UCREFRP Catalog Number: 7085
• Author: Eisler, R.
• Title: Polycyclic Aromatic Hydrocarbon Hazards to Fish, Wildlife, and Invertebrates
• USFW Year: 1987.
• USFW - Doc Type: A Synoptic Review.
• Copyright Material: NO

SUMMARY
This account synthesizes available technical literature on ecological and
toxicological aspects of polycyclic aromatic hydrocarbons (PAHs) in the
environment, with special reference to natural resources. Subtopics include:
chemical properties, sources, and fate; background concentrations in
biological and nonbiological samples; toxic and sublethal effects to flora and
fauna; and proposed criteria and research needs for the protection of
sensitive species.
PAHs consist of hydrogen and carbon arranged in the form of two or more
fused benzene rings. There are thousands of PAH compounds, each differing in
the number and position of aromatic rings, and in the position of substituents
on the basic ring system. Environmental concern has focused on PAHs that
range in molecular weight from 128.16 (naphthalene, 2-ring structure) to
300.36 (coronene, 7-ring structure). Unsubstituted lower molecular weight PAH
compounds, containing 2 or 3 rings, exhibit significant acute toxicity and
other adverse effects to some organisms, but are noncarcinogenic; the higher
molecular weight PAHs, containing 4 to 7 rings, are significantly less toxic,
but many of the 4- to 7-ring compounds are demonstrably carcinogenic,
mutagenic, or teratogenic to a wide variety of organisms, including fish and
other aquatic life, amphibians, birds, and mammals. In general, PAHs show
little tendency to biomagnify in food chains, despite their high lipid
solubility, probably because most PAHs are rapidly metabolized. Inter- and
intraspecies responses to individual PAHs are quite variable, and are
significantly modified by many inorganic and organic compounds, including
other PAHs. Until these interaction effects are clarified, the results of
single substance laboratory tests may be extremely difficult to apply to field
situations of suspected PAH contamination.
PAHs are ubiquitous in nature--as evidenced by their detection in
sediments, soils, air, surface waters, and plant and animal tissues--primarily
as a result of natural processes such as forest fires, microbial synthesis,
and volcanic activities. Anthropogenic activities associated with significant
production of PAHs--leading, in some cases, to localized areas of high
contamination--include high-temperature (>700 °C) pyrolysis of organic
materials typical of some processes used in the iron and steel industry,
heating and power generation, and petroleum refining. Aquatic environments
may receive PAHs from accidental releases of petroleum and its products, from
sewage effluents, and from other sources. Sediments heavily contaminated
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