A Compilation of Physical, Spectroscopic and Photophysical Properties of Polycyclic Aromatic Hydrocarbons

Abstract

Polycyclic aromatic hydrocarbons (PAH),t also known as polynuclear aromatic hydrocarbons or polyarenes, constitute a large class of organic compounds. They are formed and released into the environment through natural and man-made sources. Natural sources include volcanoes and forest fire, while the man-made sources come from wood burning, automobile exhaust, industrial power generators, incinerators, production of coal tar, coke, asphalt and petroleum, incomplete combustion of coal, oil, gas, garbage, tobacco and charbroiled meat. Polycyclic aromatic heterocyclic analogs containing one or more nitrogen, oxygen or sulfur atoms are also present in substantial quantities in coal tar and petroleum residues produced during the refining process. In the atmosphere, they are principally generated from the combustion of fossil fuels, wood or forest burning, refuse burning and coal tar. Although anthropogenic sources account for the major portion of atmospheric PAH pollution (l), vehicle emissions are believed to be responsible for 35% of the total PAH emission in highly populated and industrialized urban areas of the United States (2). Deposition of PAH in surface and ground waters can take place from a variety of sources such as airborne PAH, municipal wastewater discharge, effluents from wood treatment plants and other industries, oil spills and petroleum pressing. Accumulation of PAH in soils is believed to result from atmospheric deposition after long-range transport. The concentration of PAH found in soil around urban and industrialized areas are sometimes up to two orders of magnitude higher than those in less-developed areas (derived from forest fires and airborne pollution). Once released into the environment, PAH can partition between air, water, soil or sediments. An extensive body of work on this subject has appeared in the literature in recent years. Representative examples include partitioning of PAH between the gas and suspended particle phase (3,4), aidwater