| Title: | Integration of traditional and innovative characterization techniques for flux-based assessment of dense non-aqueous phase liquid (DNAPL) sites |
| Author(s): | Basu NB; Suresh P; Rao C; Poyer IC; Nandy S; Mallavarapu M; Naidu R; Davis GB; Patterson BM; Annable MD; Hatfield K; |
| Address: | "School of Civil Engineering, Purdue University, West Lafayette, IN 47907-2051, USA. nbasu@purdue.edu" |
| DOI: | 10.1016/j.jconhyd.2008.12.005 |
| ISSN/ISBN: | 1873-6009 (Electronic) 0169-7722 (Linking) |
| Abstract: | "Key attributes of the source zone and the expanding dissolved plume at a trichloroethene (TCE) site in Australia were evaluated using trends in groundwater monitoring data along with data from on-line volatile organic compound (VOC) samplers and passive flux meters (PFMs) deployed in selected wells. These data indicate that: (1) residual TCE source mass in the saturated zone, estimated using two innovative techniques, is small ( approximately 10 kg), which is also reflected in small source mass discharge ( approximately 3 g/day); (2) the plume is disconnecting, based on TCE concentration contours and TCE fluxes in wells along a longitudinal transect; (3) there is minimal biodegradation, based on TCE mass discharge of approximately 6 g/day at a plume control plane approximately 175 m from source, which is also consistent with aerobic geochemical conditions observed in the plume; and (4) residual TCE in the vadose zone provides episodic inputs of TCE mass to the plume during infiltration/recharge events. TCE flux data also suggest that the small residual TCE source mass is present in the low-permeability zones, thus making source treatment difficult. Our analysis, based on a synthesis of the archived data and new data, suggests that source treatment is unwarranted, and that containment of the large TCE plume (approximately 1.2 km long, approximately 0.3 km wide; 17 m deep; approximately 2000-2500 kg TCE mass) or institutional controls, along with a long-term flux monitoring program, might be necessary. The flux-based site management approach outlined in this paper provides a novel way of looking beyond the complexities of groundwater contamination in heterogeneous domains, to make intelligent and informed site decisions based on strategic measurement of the appropriate metrics" |
| Keywords: | Australia Fresh Water/*chemistry Time Factors Trichloroethylene/*analysis/chemistry Volatile Organic Compounds/analysis; |
| Notes: | "MedlineBasu, Nandita B Suresh, P Rao, C Poyer, Irene C Nandy, Subhas Mallavarapu, Megharaj Naidu, Ravi Davis, Greg B Patterson, Bradley M Annable, Michael D Hatfield, Kirk eng Research Support, Non-U.S. Gov't Netherlands 2009/02/13 J Contam Hydrol. 2009 Apr 1; 105(3-4):161-72. doi: 10.1016/j.jconhyd.2008.12.005. Epub 2008 Dec 25" |
