Phytoremediation of creosote-contaminated surface soil

摘要

At the site of a former creosote treatment facility, a grass phytoremediation field study was initiated in July 1997. This study is part of a larger site remediation project. The site is contaminated with polycyclic aromatic hydrocarbons (PAHs). A grass study area and a test matrix consisting of 36 planted (fescue and rye grasses) and unplanted cells was designated. The focus of the study was to evaluate PAH remediation in fertilized unplanted, fescue and rye grass soil. Cell soil samples were collected from a depth of 15 to 21cm. Data from four sampling periods, t=0, t=9, 12 and 17 months, is presented. The six most prevalent PAHs, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene and chrysene, were quantified. At t=9 months, substantial loss of the five lowest molecular weight (LMW) PAHs had occurred and was attributed to natural attenuation. Phytoremediation did not enhance removal of the 5 LMW PAHs. During the first 9 months, below average precipitation delayed grass root development. Between t=9 and 12 months, above average precipitation was experienced and accelerated chrysene removal rates occurred in planted cells. Over the last 8 months of the study, minimum concentrations of acenaphthene, fluorene and phenanthrene were attained. Increased PAH aqueous solubility correlated to decreased constituent soil concentrations.