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.

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

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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