Balance De Pce

Environmental Pollution 157 (2009) 2564–2569

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Environmental Pollution
journal homepage: www.elsevier.com/locate/envpol

A mass balance study of the phytoremediation of perchloroethylene-contaminated groundwater
C. Andrew James a, Gang Xin b, Sharon L. Doty c, Indulis Muiznieks c, Lee Newman d, Stuart E. Strand a, *
a

University of Washington,Department of Civil and Environmental Engineering, Seattle, WA, USA Hydranautics, 401 Jones Rd., Oceanside, CA 92058, USA University of Washington, College of Forest Resources, Seattle, WA, USA d Brookhaven National Laboratory, Biology Department, Upton, NY, USA
b c

A chlorine balance performed on a planted test bed with PCE-contaminated water demonstrated VOC mass reduction of 99% andcomplete dechlorination.

a r t i c l e i n f o
Article history: Received 29 July 2008 Received in revised form 17 December 2008 Accepted 27 February 2009 Keywords: Phytoremediation Perchloroethylene Mass balance

a b s t r a c t
A mass balance study was performed under controlled field conditions to investigate the phytoremediation of perchloroethylene (PCE) by hybrid poplar trees. Watercontaining 7–14 mg LÀ1 PCE was added to the test bed. Perchloroethylene, trichloroethylene, and cis-dichloroethylene were detected in the effluent at an average of 0.12 mg LÀ1, 3.9 mg LÀ1, and 1.9 mg LÀ1, respectively. The total mass of chlorinated ethenes in the water was reduced by 99%. Over 95% of the recovered chlorine was as free chloride in the soil, indicating near-complete dehalogenation of the PCE.Transpiration, volatilization, and accumulation in the trees were all found to be minor loss mechanisms. In contrast, 98% of PCE applied to an unplanted soil chamber was recovered as PCE in the effluent water or volatilized into the air. These results suggest that phytoremediation can be an effective method for treating PCE-contaminated groundwater in field applications. Ó 2009 Elsevier Ltd. Allrights reserved.

1. Introduction Due to its widespread use, perchloroethylene (PCE) is one of the most common environmental pollutants found at National Priority List and Superfund sites (United States Environmental Protection Agency, 2007). A recent survey of groundwater in the United States found that PCE was detected in 11% of the samples analyzed (Moran et al., 2007). Perchloroethylene isassociated with health risks such as liver and kidney damage, spontaneous abortions, and is listed as a probable human carcinogen (ATSDR, 1997). Although peak production occurred in 1980, it continues to be used in nearly 30 000 dry cleaning operations in the United States, presenting an ongoing risk of accidental releases (Doherty, 2000). As such, finding inexpensive and reliable remediation methodsis an ongoing priority. The phytoremediation of PCE is potentially advantageous based on economics and aesthetics. Several studies have demonstrated
* Corresponding author at: College of Forest Resources, P.O. Box 352100, University of Washington, Seattle, WA 98195, USA. Tel.: þ1 206 543 5350. E-mail address: sstrand@u.washington.edu (S.E. Strand). 0269-7491/$ – see front matter Ó 2009 ElsevierLtd. All rights reserved. doi:10.1016/j.envpol.2009.02.033

the effectiveness of phytoremediation against PCE in the laboratory (Nzengung and Jeffers, 2001; Nzengung et al., 2003) and other chlorinated hydrocarbons such as trichloroethylene (TCE) and carbon tetrachloride (CT) in both field and laboratory settings (Anderson et al., 1993; Anderson and Walton, 1995; Newman et al., 1999; Shaw andBurns, 2003; Walton and Anderson, 1990; Wang et al., 2004). However, field studies on the phytoremediation of PCE are rare. Recent field studies have focused on the utility of tree sampling for subsurface chloroethene plume identification (Gopalakrishnan et al., 2007; Larsen et al., 2008; Sorek et al., 2008) or evaluated various tree species for potential phytoremediation application (Stanhope et al.,...