ABSTRACT
Extensive soil contamination with phenolics and polynuclear aromatic hydrocarbons (PAH) resulted from both process operations and improper waste disposal, and subsequent leaching of contaminants into groundwater below industrial sites is another serious environmental concern. Coal tar has high levels of aromatic compounds such as xylene, toluene, benzene, and naphthalenes and other PAHs. Extensive PAH degradation has been observed in landfarming, slurry, and sequencing batch reactor systems. Evolution of 14CO2 from 14C-labeled PAHs in the molecular weight range of naphthalene to pyrene commonly accounts for 40–70 percent of the applied 14C activity during biological treatment. Soil PAH concentrations were determined by extraction with methylene chloride using an ultrasonic processor and gas chromatography. Phenanthrene is a commonly used model substrate in studies of PAH degradation, and due to its low vapor pressure, losses due to volatilization are expected to be negligible. J. Keck et al. determined the effect of the constituent matrix on the rate of disappearance of 13 PAHs in soil.
