Phytoremediation of a Perchloroethylene Contaminated Site in LaSalle, Illinois, with Populus Clones- A Field Evaluati

1. Phytoremediation of a Perchloroethylene Contaminated Site in LaSalle, Illinois, with Populus Clones- A Field Evaluation JG Isebrands1, DL Rockwood2, RB Hall3, AS Lindner2,A Pacheco2, N Brown4, and RM Lange5 1Environmental Forestry Consultants, New London, WI 54961, efcllc@athenet.net, 2University of Florida, Gainesville, FL 32611, 3Iowa State University, Ames, IA 50011, 4Ecology and Environment, Chicago, IL 60602, 5Illinois Environmental Protection Agency, LaSalle, IL 61301 INTRODUCTION Populus trees are being used throughout North America for phytoremediation (phyto) of chlorinated solvent contaminated soil and groundwater. Much of the phyto work has been with only a few poplar clones including the clone Eugenei (DN-34). One of the challenges of phyto is to find the proper clone for the specific site through field evaluations. Another challenge is to find non-destructive field methods for assessing solvent uptake. The former LaSalle Electric Utilities site in LaSalle, IL has an perchloroethylene (PCE) contaminated plume of soil and groundwater. Our work is focused on evaluating the effectiveness of using phyto with poplar clones at the LaSalle site. MATERIALS AND METHODS • Rooted cuttings of 18 Populus clones from Iowa State University were planted upon the PCE contaminated plume in the spring of 2002 • Replicated randomized block design • Tree growth, health, and survival was monitored several times each year • In July, 2003 heterotrophic and methanotrophic microbes were collected from soil and rhizosphere near trees within and outside the plume and analyzed with standard methods • In October, 2003 eight trees from within and outside plume were excavated to assess PCE uptake • Stem cores and disks and branch samples were collected for field screening with E&E Color Tech method and lab gas chromatography Fig 1.Enumeration of microorganisms in rhizosphere soil and in/on roots of Poplar I 45/51 trees. PCE site, LaSalle. *At low [PCE] depths of 30 to 90 cm no roots were observed. I Table 2. Comparison of poplar clones at LaSalle for 20 month height (H, m), DBH (cm), and D2H (dm3) at LaSalle, percent of Eugenei 20 month D2H at LaSalle, percent of Eugenei tree volume regionally, Melampsora leaf rust incidence at LaSalle in 2002 and relative incidence regionally (N=none, L=light, M=moderate), freeze incidence (T=trace, M=moderage, S=severe) at LaSalle in 2002, and estimated water uptake (L(gal) at LaSalle in 2003 Table 1. Identity, pedigree, and origin of 18 poplar clones under evaluation at LaSalle Electric Utilities, LaSalle, IL site ClonePedigreeOrigin (E=Exotic) 7300501 P. deltoides Southern Illinois 119.16 P. deltoides Ohio x (Nebraska x Minnesota) 220-5 P. deltoides Ohio 252-4 P. deltoides Central Missouri 42-7 P. deltoides Southern Indiana 51-5 P. deltoides Southern Ohio 80x00601 P. deltoides Southern Illinois x Southern Illinois 80x01015 P. deltoides Southern Illinois x Southern Illinois 80x01107 P. deltoides Southern Illinois x Southern Illinois ISU 25-21 P. deltoides Southern Illinois x Southern Illinois ISU 25-35 P. deltoides Southern Illinois x Southern Illinois ISU 25-R4 P. deltoides Southern Illinois x Southern Illinois ISU 25-R5 P. deltoides Southern Illinois x Southern Illinois Eugenei P. deltoides x P. nigra North America x Europe I45/51 P. deltoides x P. nigra North America x Europe Belgian 25 P. nigra x P. maximowiczii Europe x Japan NM-2 P. nigra x P. maximowiczii Europe x Japan Crandon P. alba x P. grandidentata Europe x Southern Iowa • OBJECTIVES • OVERALL OBJECTIVE • To determine the effectiveness of phytoremediation with Populus trees to clean up a PCE contaminated plume of soil and groundwater at the former LaSalle Electric Utilities site in LaSalle, IL • SPECIFIC OBJECTIVES • Compare poplar clone performance for growth, water uptake, and PCE uptake, and rank them according to the industry standard clone, Eugenei (DN-34) • Determine numbers of microbes capable of degrading chlorinated solvents in rhizosphere and soil near trees within and outside the PCE plume • Develop a non-destructive inexpensive field method for monitoring PCE uptake in trees • RESULTS • Growth of Populus clones at the site was impressive – average height • (4.1 m) and diameter (3.3 cm) in 2 years • Clonal differences in total biomass and water uptake were significant, and less on the concentrated plume • Numbers of microorganisms in rhizosphere soil, and on poplar roots at • several depths were greater than control soil • Significant uptake of PCE was found in stems and branches of 3 poplar • clones • Lab analyses correlated well with field screening using E&E Color Tech • method • CONCLUSIONS • Our results including growth, microbe numbers, water • uptake, and PCE uptake indicate poplar clones may be • effective in PCE phytoremediation • Choice of poplar clone is important • Poplar trees enhance microbe numbers capable of • degrading chlorinated compounds in rhizosphere and • soil • Non-destructive field methods for monitoring PCE • uptake show promise • Acknowledgements: Financial and in-kind support from: • Illinois Environmental Protection Agency • Ecology and Environment, Inc., Chicago, IL