Natural attenuation of PAHs and benzene at the stockton MGP site

摘要

This field-scale study documents the lines of evidence showing that natural attenuation of polycyclic aromatic hydrocarbons (PAHs) and benzene is taking place in groundwater beneath the Stockton former Manufactured Gas Plant (MGP) site in Stockton, California. Prior to soil remediation, total PAH-concentration reductions have ranged between 60 and 95 percent over six years and benzene concentrations have decreased by 90 to 99 percent. Isoconcentration plots of total PAHs and benzene over time show a stable and in some instances, a shrinking plume. There is evidence of biodegradation of these compounds from geochemical results along the groundwater flow path through the site. It is believed that after soil source area remediation is completed, natural attenuation will continue to significantly reduce the chemicals of concern in groundwater through physical, chemical, and biological remediation processes.