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, [email protected], 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.
I
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
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.
Control(grass cover)
0
1
2
3
4
5
6
7
8
9
10Low [PCE]
Soil depth (cm)
log
(cel
l cou
nt o
r MPN
) g-1
dry
soi
l or f
resh
root
0
1
2
3
4
5
6
7
8
9
10
CFU hts-soil CFU hts-roots MPN mts-soilMPN mts-roots
High[PCE]
* *
OBJECTIVESOVERALL 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
Table 1. Identity, pedigree, and origin of 18 poplar clones under evaluation at LaSalle Electric Utilities, LaSalle, IL site
Clone Pedigree Origin (E=Exotic)
7300501 P. deltoides Southern Illinois119.16 P. deltoides Ohio x (Nebraska x Minnesota)220-5 P. deltoides Ohio252-4 P. deltoides Central Missouri42-7 P. deltoides Southern Indiana51-5 P. deltoides Southern Ohio80x00601 P. deltoides Southern Illinois x Southern Illinois80x01015 P. deltoides Southern Illinois x Southern Illinois80x01107 P. deltoides Southern Illinois x Southern IllinoisISU 25-21 P. deltoides Southern Illinois x Southern IllinoisISU 25-35 P. deltoides Southern Illinois x Southern IllinoisISU 25-R4 P. deltoides Southern Illinois x Southern IllinoisISU 25-R5 P. deltoides Southern Illinois x Southern IllinoisEugenei P. deltoides x P. nigra North America x EuropeI45/51 P. deltoides x P. nigra North America x EuropeBelgian 25 P. nigra x P. maximowiczii Europe x JapanNM-2 P. nigra x P. maximowiczii Europe x JapanCrandon P. alba x P. grandidentata Europe x Southern Iowa
D2H (Volume estimate) Percent of Eugenei
Leaf Rust
Freeze
Estimated Water Uptake
Clone
H DBH LaSalle LaSalle Region LaSalle Region LaSalle LaSalle
119.16 4.6 2.67 3.29 68% 117% L T 7300501 4.4 3.64 5.83 120% 206% Some L 220-5 4.1 3.56 5.21 107% 119% L T 252-4 3.9 3.04 3.64 75% 188% Some L T 42-7 3.2 2.35 1.73 36% 239% Heavy L M 51-5 4.5 3.99 7.20 148% - L T 80x00601 4.0 3.06 3.75 77% 88% L M 80x01015 4.6 3.35 5.15 106% - L M 80x01107 4.3 3.89 6.51 134% 86% L T ISU 25-21 4.8 4.23 8.54 176% 180% L ISU 25-35 4.7 3.58 5.96 123% 424% M T ISU 25-R4 5.1 4.51 10.28 212% 251% L 947(249) ISU 25-R5 5.0 3.78 7.10 146% 359% M T Eugenei 4.3 3.35 4.85 - - L S 798(210) I 45/51 3.4 1.99 1.36 28% - L S 764(201) Belgian 25 3.5 3.07 3.32 68% 141% Some L S NM-2 2.3 2.78 1.81 37% 144% N S Crandon 3.5 3.28 3.81 78% 113% None N S Mean 4.1 3.34 4.60 796(209)
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
