In situ phytoremediation of PAHcontaminated soil

Authors: Mingming Sun Dengqiang Fu Ying Teng Yuanyuan Shen Yongming Luo Zhengao Li Peter Christie

Publish Date: 2011/05/24

Volume: 11, Issue: 6, Pages: 980-989

PDF Link

Abstract

Alfalfa and tall fescue were grown in monoculture and intercropped for 7 months in contaminated field soil Soil and plant samples were analyzed for PAHs Plant biomass densities of PAHdegradation soil bacteria soil microbial biomass C and N enzyme activities and the physiological profile of the soil microbial community were determinedAverage removal percentage of total PAHs in intercropping 305 was significantly higher than in monoculture 199 or unplanted soil −06 About 75 of 3ring 123 of 4ring and 172 of 5+6ring PAHs were removed from the soil by alfalfa with corresponding values of 251 104 and 301 for tall fescue Intercropping significantly enhanced the remediation efficiency About 189 of 3ring 309 of 4ring and 334 of 5+6ring PAHs were removed by the intercropping system Higher counts of soil culturable PAHdegrading bacteria and elevated microbial biomass and enzyme activities were found after intercropping Soil from intercropping showed significantly higher p  005 average wellcolor development obtained by the BIOLOG Ecoplate assay and Shannon–Weaver index compared with monocultureCropping promoted the dissipation of soil PAHs Tall fescue gave greater removal of soil PAHs than alfalfa and intercropping was more effective than monoculture Intercropping of alfalfa and tall fescue may be a promising in situ bioremediation strategy for PAHcontaminated soilsPolycyclic aromatic hydrocarbons PAHs are of considerable concern because they are potentially toxic to humans and are persistent contaminants in the environment Wilcke 2007 Phytoremediation the use of plants to remediate contaminated soil has been described as a promising approach to remediate soils contaminated with persistent organic pollutants such as PAHs Chen et al 2003 Huang et al 2004 Phillips et al 2009 During the last few decades numerous plant species including alfalfa and tall fescue have been found to be promising candidates for phytoremediation of PAHs Liu et al 2004 Parrish et al 2004 Balcom and Crowley 2009 Parrish et al 2004 reported 24 dissipation of total PAHs in composted soil in the presence of tall fescue Greenhouse experiments have demonstrated enhanced removal of PAHs when alfalfa was planted compared with unplanted controls Liu et al 2004 These results were obtained using single plant species and little is known about how plant species and cropping patterns affect the processes by which phytoremediation removes PAHs on a field scale Meng et al 2011 Wei and Pan 2010 More information is therefore required on the in situ phytoremediation potential of intercropped species such as alfalfa and tall fescueThe ultimate goals of any remediation approach must be to remove the contaminants from the soil and to restore the capacity of the soil to function according to its potential Epelde et al 2009 Soil microorganisms are very sensitive to any ecosystem function shifts because their activity and diversity are rapidly altered by perturbation Margesin et al 2000 Andreoni et al 2004 Joner et al 2004 Microbiological parameters such as microbial biomass enzyme activities and the diversity of soil microbial communities may serve as important indices of the impact of pollution on soil health Labud et al 2007 Epelde et al 2008 Teng et al 2010 Tu et al 2011 The aims of the present work were therefore to investigate the in situ phytoremediation potential of intercropped alfalfa and tall fescue and to examine associated changes in microbial activities in a PAHcontaminated soilA chromatographic grade standard mixture consisting of the 16 PAHs prioritized by the US EPA naphthalene acenaphthylene acenaphthene fluorene phenanthrene anthracene fluoranthene pyrene benzoaanthracene chrysene benzobfluoranthene benzokfluoranthene benzoapyrene dibenzahanthracene benzoghiperylene and indeno123cdpyrene was purchased from AccuStandard Inc New Haven CT All the other chemicals used were of analytical or chromatographic grade

Keywords: