Polycyclic Aromatic Hydrocarbons(PAH's) are one of the more plentiful organic contaminants in the environment, and in many respects, can be considered one of the more dangerous to living organisms(1).  PAH's are produced both naturally(forest fires) and anthropomorphically(fossil fuel refinery and combustion) through the incomplete combustion of organic matter(2).  PAH's are partitioned from the atmosphere to soil, sediment, and water systems.
(forest fires.2002)

Movement and degradation of PAH's in the natural environment is restricted due to its molecular structure and its lipophilic, hydrophobic nature(2). These characteristics allow for an allevated rate of sorption to organic particles, thus increasing accumulation throughout the ecosystem. PAH's adherence and accumulation in the environment poses a threat to the health of all living organisms that utilize all PAH contaminated sites.  All PAH's are toxic, but the major concern is high molecular weight PAH's (4+ rings) which can be carcinogenic and/or mutagenic(3).  PAH's lipophilic nature, high toxicity, and persistance in the environment culminate in an increased risk of biomagnification throughout the food chain, which eventually works its way into the human population, and requires the direct implementation of remedial technologies.
(USGS.2000)

Remediation of PAH contaminated sites can be accomplished through various techniques, such as Phytoremediation ( the use of living plants for uptake of contaminants and/or the reduction of soil contaminant concentrations), Natural Attenuation ( the use of natural geologic, biotic factors to reduce or eliminate contaminants), and Bioremediation ( the use of microbes to reduce, eliminate contaminants).  To my knowledge, the preponderance of evidence in field and laboratory studies suggest that Bioremediation is the most effective and widely used method in dealing with PAH contamination (11).

Bioremediation is a process that utilizes naturally occuring microorganisms (bacteria, fungi) to degrade contaminants in soil and sediment environments (10).  Studies have proven that the use of indigenous microbes( microbes living on the contaminated site) enhances Bioremediation capabilities (12).  Also, exploitation of the naturally occurring symbiosis between the microbes and the living plant, in the Rhizosphere, can increase Bioremediation one hundred fold (4).
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