phytoremediation of arsenic contaminated soils by fast growing eastern cottonwood

92 Pages·2001·1.82 MB·English

PHYTOREMEDIATION OF ARSENIC CONTAMINATED SOILS BY FAST
GROWING EASTERN COTTONWOOD Populus deltoides (Bartr.) CLONES

By

RICHARD WILLIAM CARDELLINO

A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA

2001
ACKNOWLEDGMENTS

I extend my gratitude to Dr. Donald Rockwood for the opportunity to participate
in bioenergy and remediation studies of Eucalyptus and Populus and also to my
committee members Drs. P. K. Nair and Thomas Crisman for additional mentoring.
This thesis was possible due to the work started by Dr. Gillian Alker, and I thank
her for the guidance and opportunity to study phytoremediation. I also thank Dr. Lena Ma
for advice on soil remediation.
The Phyto Lab staff and students have been essential for the research done, and I
am very thankful to them.
My special thanks go to my Family.
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TABLE OF CONTENTS
page

ACKNOWLEDGMENTS..................................................................................................ii
LIST OF TABLES...............................................................................................................v
LIST OF FIGURES..........................................................................................................vii
ABSTRACT.....................................................................................................................viii
CHAPTERS
1 INTRODUCTION..........................................................................................................1
Phytoremediation and Short Rotation Intensive Culture...........................................2
Cottonwood in Short Rotation Intensive Culture.......................................................2
Hypotheses and Objectives........................................................................................3

2 LITERATURE REVIEW...............................................................................................5
As Contamination......................................................................................................5
As and Soil Interactions.............................................................................................7
As and Plant Interactions...........................................................................................9
As Toxicity in Plants................................................................................................12
Phytoremediation.....................................................................................................14
Biomass vs Hyperaccumulation...............................................................................17
Clonal Selection.......................................................................................................19
Chelates in As Phytoremediation.............................................................................22

3 MATERIALS AND METHODS..................................................................................28
Field Studies.............................................................................................................28
Laboratory and Greenhouse Studies........................................................................34

4 RESULTS AND DISCUSSION...................................................................................38
Field Studies.............................................................................................................38
Laboratory and Greenhouse Studies........................................................................50

5 CONCLUSIONS...........................................................................................................54
6 FUTURE RESEARCH.................................................................................................57
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APPENDICES
A TABLES.........................................................................................................................58
B FIGURES.......................................................................................................................62
C ANOVA.........................................................................................................................72
LITERATURE CITED......................................................................................................77
BIOGRAPHICAL SKETCH.............................................................................................83
iv
LIST OF TABLES

Table page

1-1 Variables assessed in three field sites and/or one greenhouse experiment..................4
3-1 Four treatments applied to clone ST 121 grown in Archer contaminated soil and
receiving ammonium nitrate. …................................................................................35
4-1 Archer clones least squares means and standard errors in parentheses for height,
diameter, and leaf number for November 2000 and May 2001. ...............................38
4-2 Concentrations (mg/kg) of As, Cu, and Cr in leaf tissue of selected Archer clones
in November 2000. ....................................................................................................40
4-3 Concentrations (mg/kg) of As in leaf and stem tissue of 11 Archer clones in May
2001. ..........................................................................................................................40
4-4 Plant tissue As concentration (mg/kg) in naturally occurring vegetation at Quincy
in November 2000......................................................................................................41
4-5 Cluster means for height (cm), diameter (mm), leaf number, and/or weight (g)
from Quincy cluster analysis for November 2000, February 2001, and May 2001. .42
4-6 Best performing clones by Quincy cluster analysis for height (H in cm), diameter
(D in mm), leaf number (LN) and/or dry weight (W in g) in November 2000,
February 2001, and May 2001. .................................................................................42
4-7 Leaf As concentration (mg/kg) of selected clones at Quincy in 2000 and 2001. .....43
4-8 Concentrations (mg/kg) of As in Quincy soil samples taken at three depths in
August and September 2000. ....................................................................................44
4-9 Comparison of soil As at 0.15 m and tissue As concentration (mg/kg) for a given
clone for September 2000. ........................................................................................45
4-10 Cluster means for height (cm), diameter (mm), leaf number, and/or weight (g)
from Kent cluster analysis for November 2000, February 2001, and May 2001......48
4-11 Best performing clones by cluster analysis at Kent for November 2000, February
2001, and May 2001. ................................................................................................48
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4-12 Comparison of height between clones for Quincy (contaminated) and Kent
(uncontaminated). .....................................................................................................49
4-13 Greenhouse experiment means and multiple comparisons for height and percent
leaf mortality. …........................................................................................................50
4-14 Greenhouse experiment tissue and soil As analysis. …............................................51

vi
LIST OF FIGURES

Figure page

4-1 Clonal mean unaffected leaf area in in vitro leaf disc test for October 1999. ..........53
4-2 Clonal mean unaffected leaf area in in vitro leaf disc test for May 2001. ................53

vii
Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

PHYTOREMEDIATION OF ARSENIC CONTAMINATED SOILS BY FAST
GROWING EASTERN COTTONWOOD (POPULUS DELTOIDES) CLONES

By

Richard William Cardellino

December, 2001

Chairman: Donald L. Rockwood
Major Department: Forest Resources and Conservation

Florida has many arsenic (As) contaminated soils due to past agricultural
pesticide and chromium copper arsenate (CCA) wood preservative use. The cost of
conventional chemical and physical remediation is high, and therefore most contaminated
soils remain untreated. Phytoremediation, in combination with woody biomass
production, could be an economically feasible method.
Eighty-five cottonwood (Populus deltoides) clones were assessed at two CCA
contaminated sites and a clay-settling pond in Florida for their ability to grow and tolerate
or extract As metals from soils. Variables used were height, diameter at 1 cm above
ground, biomass, number of leaves, and leaf and stem concentration of As. Cluster
analysis was used to rank clones using all variables. The overall better performing clones
were ST 71, ST 201, ST 202, ST 259, and S13C1.
Where soil As levels ranged from 33 to 259 mg/kg, leaf As uptakes were 15 to 29
mg/kg in the first growing season, and 4.1 to 6.4 mg/kg in the second growing season.
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For clone ST1, leaf uptake was 5.5 mg/kg and stem uptake was 1.4 mg/kg, confirming
that stem uptake is around 1/3 of leaf uptake. Where soil As levels ranged from 1.6 to 64
mg/kg, and a hardpan was present at 2 ft, leaf As uptakes were BDL to 1.1 mg/kg. Most
plants sampled growing at lower levels of As at .5-ft, showed uptake at BDL. Plants
growing at higher soil As levels showed some As uptake.
Clone ST 201was used in the greenhouse to evaluate EDTA and histidine for
uptake enhancement of As. EDTA produced rapid leaf mortality. Histidine plus EDTA
helped the plants cope with the rapid uptake of As and permitted accumulation of up to
23 mg/kg As.
A leaf disk test for screening clones in vitro was performed for identifying clones
suitable for phytoremediation. Leaf segments were placed in a petri dish containing a
solution with CCA. Clones that showed the least amount of necrosis were considered
most appropriate for phytoremediation. ST 259 had a higher unaffected leaf area than
110804. This matched the performance in the field.
Cottonwood is potentially easy to establish, is fast growing, can produce 10
t/ha/yr of biomass, and achieve tissue concentrations of up to 10 mg/kg of As. The
removal of up to 100 g/ha of As per year is possible.
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CHAPTER 1
INTRODUCTION

Florida has many arsenic (As) contaminated soils due to past pesticide uses: cattle
dipping vats, and chromated copper arsenate (CCA) wood preservation plants. There is a
high cost associated with site remediation using conventional chemical and physical
methods, and therefore most contaminated soils remain untreated (Alker et al., 2000).
Phytoremediation is the removal of contaminants from soil and groundwater using plants.
The cost of phytoremediation for 0.4 hectares of a Pb contaminated site is
$60,000, compared to the $400,000 cost of excavating and landfilling (US EPA, 1998).
Phytoremediation in combination with woody biomass production could be an
economically feasible way of treating these sites. Phytoremediation with woody biomass
is most feasible in low to medium level As contaminated soils.
Phytoremediation uses plants to remove, transfer, stabilize, or destroy organic or
inorganic contaminants in soil, sediment, or water (US EPA, 1998). Plants accomplish
this task by three mechanisms: uptake of contaminants via roots and accumulation in
plant tissue, release of root exudates and enzymes that detoxify contaminants directly or
stimulate microbial detoxification, and enhancement of mineralization in the soil
(Schnoor et al., 1995). Soil amendments are sometimes necessary to make metal
contaminants bioavailable for uptake. Contaminants such as As will not break down, but
can be taken up and stored in plant biomass.

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