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Relation among Subspecies of Cucurbita in Phyto-extraction
of Field-weathered p,p’-DDE and Exudation of
Citric Acid from Roots
Martin
P.N. Gent, Connecticut Agricultural Experiment Station (CAES),
New Haven CT
Zakia Parrish, Connecticut Agricultural Experiment Station
(CAES), New Haven CT
Jason C. White, Connecticut Agricultural Experiment
Station (CAES), New Haven CT
Uptake
of Polycyclic Aromatic Hydrocarbons in Spartina
Alterniflora – Evaluating Risk in Salt Marsh Vegetation
Alison
W. Watts, University of New Hampshire, Durham, NH
Thomas P. Ballestero, University of New Hampshire, Durham,
NH
Kevin H. Gardner, University of New Hampshire, Durham, NH
Phytoremediation
of Lead Contaminated Soils in the Urban Residential
Environment using Seed Mustard
Ilana
S. Goldowitz, Cornell University, Ithaca NY
Joshua Goldowitz, Rochester Institute of Technology,
Rochester NY
Rhizodegradation
of RDX Contaminated Soils Using Grass Exudates
Afrachanna
D. Butler, Jackson State University, Vicksburg, MS
Victor F. Medina, U.S. Army Corps of Engineers-Engineer
Research & Development Center, Vicksburg, MS
Plant
Assisted Bioremediation of Pollutants from Aquaculture
Water
Kishore
K. Krishnani, Stevens Institute of Technology, Hoboken, NJ
Xioaguang Meng, Stevens Institute of Technology,
Hoboken, NJ
Phytoremediation
Applications for Arsenic in Northern Climates
Michael
J. Blaylock, Edenspace Systems Corporation, Dulles, VA
Mark P. Elless, Edenspace Systems Corporation, Dulles, VA
Charissa Y. Poynton, Edenspace Systems Corporation,
Dulles, VA
Can
We Predict the Best Plants for the Phytoremediation of
Organic Contaminants?
Chris
D. Collins, Imperial College, South Kensington, London
Neil J. Willey, University of the West of England,
Frenchay, Bristol
Relation
among Subspecies of Cucurbita in Phyto-extraction of
Field-weathered p,p’-DDE and Exudation of Citric
Acid from Roots
Martin
P.N. Gent, Connecticut Agricultural Experiment Station (CAES),
Department of Forestry and Horticulture, 123 Huntington
Street, New Haven CT 06504, Tel: 203-974-8489, Fax:
203-974-8502, Email:
Martin.Gent@po.state.ct.us
Zakia Parrish, Department of Soil and Water, Connecticut
Agricultural Experiment Station (CAES), 123 Huntington
Street, New Haven CT 06504
Jason C. White, Department of Soil and Water, Connecticut
Agricultural Experiment Station (CAES), 123 Huntington
Street, New Haven CT 06504
Field
experiments have shown that two subspecies of Cucurbita
pepo (summer squash) differ in phyto-extraction of
field-weathered p,p’-DDE.
Three cultivars were selected from each of the
subspecies; Cucurbita pepo ssp pepo
(zucchini) with a greater ability to take up DDE, and Cucurbita
pepo ssp ovifera (summer squash) with a lesser
ability to take up DDE. When grown in the field,
subspecies pepo
phyto-extracted about 1.0% of the p,p’-DDE, while
subspecies ovifera removed less than 0.2% of the contaminant. To evaluate
whether exudation of organic acids from the roots was
involved in uptake of weathered DDE, these cultivars were
grown under hydroponic conditions. Phosphorus nutrition
played a significant role in exudation of organic acids
into the hydroponics solution. For both subspecies, the
better the phosphorus nutrition, the more tartaric and
less citric acid was exuded. However, subspecies pepo
showed a greater increase in citric acid exuded under
phosphorus depletion than ovifera. This was the only response to phosphorus depletion that
differed among subspecies. Thus, in a comparison among
subspecies of Cucurbita
pepo, the response to phosphorus depletion of
exudation of citric acid was related to the ability to
accumulate a higher concentration weathered organic
contaminants in soil when grown in the field.
Uptake
of Polycyclic Aromatic Hydrocarbons in Spartina
Alterniflora – Evaluating Risk in Salt Marsh Vegetation
Alison
W. Watts, University of New Hampshire, 35 Colovos Rd,
Durham, NH 03824, Tel: 603-312-7654, Fax: 603-862-3957
Thomas P. Ballestero, University of New Hampshire, 35
Colovos Rd, Durham, NH 03824, Tel:
603-862-1405, Fax: 603-862-3957
Kevin H. Gardner, University of New Hampshire, 35 Colovos
Rd, Durham, NH 03824, Tel:
603-862-4334, Fax: 603-862-3957
Polycyclic
Aromatic Hydrocarbons (PAHs) are present in many coastal
and salt marsh sediments.
Sources include oil spills, urban runoff, and coal
gasification byproducts.
Plants affect the movement of PAHs in several ways;
they may inhibit erosion, enhance microbial degradation,
or translocate compounds.
Plant translocation can move a compound from the
soil or water into the plant.
The compound is then either stored in plant tissue,
or degraded by microbial or metabolic processes, or
excreted into the atmosphere.
Contaminants stored in plant tissue may present a
risk to the ecological community.
In
this study, uptake of PAHs was measured in Spartina
alterniflora, a common salt marsh plant.
For three months Spartina alterniflora was grown
outdoors in PAH-contaminated soil and in clean control
soil. The PAH contaminated sediment was collected from an estuary
near a former coal gasification plant, and contained an
average of 200 ug/g total PAHs.
Plant samples were also collected from a PAH-contaminated
estuarine marsh and from an uncontaminated reference site.
Plants grown in uncontaminated soil produced more
flowers, and were taller, but plants grown in contaminated
soil had more shoots, yielding a shorter, bushier
morphology. The
total above-ground biomass at the end of the growing
season was similar in the controls and PAH-grown plants.
The
harvested samples were separated into leaf and root
material and analyzed for individual PAH compounds. Most
of the samples were analyzed using a GC/MS/MS system with
a chromatoprobe direct-sample-injection device.
Small pieces of plant tissue can be analyzed
directly by this method, allowing rapid evaluation of
individual leaves or roots.
However, the detection limit is higher than
traditional extraction-injection methods due to the small
sample size and co-elution of some plant-derived
compounds.
PAHs
were detected in both root and leaf tissue.
Concentrations in root tissue were approximately an
order of magnitude higher than leaf tissue, and plant
concentration increased as soil concentration increased.
PAH concentrations in plant tissue will be compared
to ecological risk levels such as the NOAA ERM/ERLs, and
potential ecological risks will be evaluated.
Phytoremediation
of Lead Contaminated Soils in the Urban Residential
Environment using Seed Mustard
Ilana
S. Goldowitz, Cornell University, Plant Sciences Dept.,
Plant Sciences Building, Ithaca NY 14853, Tel:
585-442-2464, Email: picea_spp@yahoo.com
Joshua Goldowitz, Rochester Institute of Technology, Civil
Engineering Technology, Environmental Management &
Safety Department, 78 Lomb Memorial Drive, Rochester NY
14623, Tel: 585-475-7018, Email: jxgctp@rit.edu
Lead
contamination in the urban environment is a continuing
serious public health concern. Historically lead entered
the urban residential area though paint pigment and
gasoline additives. This legacy persists as the two most
important lead sources that affect children in the urban
environment: contaminated paint residue and contaminated
soil. One technique for remediation of lead in urban soils
is phytoremediation.. Previous research has shown Brassica
juncea (mustard) to be the most promising
phytoremediator of lead in soil. Researchers commonly use
Southern Giant Curly Leaf Mustard because it is a
hyperaccumulator of lead, has extremely high production of
mustard green biomass in a short (45 day) growing season,
and is adaptable to poor soil conditions. The authors
believe that use of this variety in the urban environment
may be problematic. The greens are favored as a food, are
easily recognized, and may be pilfered and eaten. This
research tested the hypothesis that seed mustard, which
produces abundant flowers but few greens, would be more
suitable. Two 60m2 plots were prepared in a
Greater Rochester Urban Bounty garden, located at a busy
intersection in Rochester New York’s impoverished
northeast neighborhood. One plot was sown thickly with
Southern Giant, and the other with seed mustard. As the
plants approached maturity the entire crop of Southern
Giant mustard was pilfered, but the seed mustard remained
untouched. At maturity the seed mustard produced 550g dry
biomass per m2.
Assuming similar maximum lead uptake among mustard
varieties, this would yield a lead uptake rate of up to 5
g/m2. The research also included a germination
study. Five standard seed germination tests (400 seeds
each) performed in increasingly concentrated lead
contaminated soils indicated little variation in
germination rate. Thus
seed mustard is more suitable for phytoremediation of lead
in the urban residential environment.
Rhizodegradation
of RDX Contaminated Soils Using Grass Exudates
Afrachanna
D. Butler, Jackson State University, Department of
Environmental Science, Ph.D. Program, c/o CEERD-EP-E, 3909
Halls Ferry Road, Vicksburg, MS 39180, Tel: 601-634-2808,
Fax: 601-634-3518, Email:
Afrachanna.D.Butler@erdc.usace.army.mil
Victor F. Medina, U.S. Army Corps of Engineers-Engineer
Research & Development Center, 3909 Halls Ferry Road,
Vicksburg, MS 39180, Tel: 601-634-4283, Fax: 601-634-3518,
Email: victor.f.medina@erdc.usace.army.mil
Phytoremediation
uses living plants for in situ and ex situ remediation of
contaminated soil, sludges, sediments and ground water,
and is a promising biotechnology for cleanup of
contaminated sites. Some
advantages of phytoremediation are low-cost, works well at
low-risk sites, and may operate with limited maintenance
for decades. Disadvantages of this technology are that it
may require large expense for relocating operations,
buildings, and roads at operating bases and there may be
slow plant establishment that may limit the application.
Phytoremediation
encompasses a range of processes, which includes
rhizodegradation. Rhizodegradation
is the breakdown of contaminants in the soil through
microbial activity that is enhanced by the presence of the
rhizosphere. Our
study focuses on RDX, a widely used military explosive.
It has been indicated in other phytoremediation
studies that RDX degradation inside the plant is slow and
possibly incomplete.
At the same time, phytoremediation, if effective,
could be a useful approach at active firing ranges.
This research investigates whether rhizodegradation
can be used to degrade RDX contaminated soils.
In rhizodegradation, natural substances called
plant exudates are released by the plants’ roots.
These exudates contain organic carbon that act as
nutrient sources for soil microorganisms. In our study, wild grasses will be grown hydroponically so
that the grass exudates are released from the roots into
the water. Those
grass exudates will be applied to RDX contaminated soils
and RDX degradation will be monitored.
Changes in microbial activity will also be studied.
As a result, we hope to find that the release of
the soluble organic matter from the roots of the grasses
stimulate RDX degradation.
Plant
Assisted Bioremediation of Pollutants from Aquaculture
Water
Dr. Kishore K.Krishnani,
Visiting Scientist, Centre for Environmental Engineering,
Stevens Institute of Technology, Hoboken, 07030, NJ,
Email: krishnanik@hotmail.com
Xioaguang Meng, Centre for Environmental Engineering,
Stevens Institute of Technology, Hoboken, 07030, NJ,
Email: xmeng@stevens.edu
Brackishwater aquaculture
is the fastest growing food sector, especially shrimp
farming which has emerged as a main source of employment
and income for hundreds of thousands of people. However,
agricultural, industrial and sewage wastes can contaminate
aquatic ecosystem through the discharge containing
nitrogenous toxicants, pesticides and heavy metals and can
affect the aquaculture profitability in certain areas.
Most of the previous works highlight the use of
commercially activated carbons and ion exchange resins,
which are relatively expensive and less feasible to use in
developing countries. Furthermore, activated carbon loaded
with toxicants is generally incinerated or disposed off on
land, thereby causing environmental pollution through
different routes. An emerging field of interests is
employing certain plants which possess the natural ability
to uptake heavy metals for the remediation of environment.
In addition, plants release exudates and enzymes that
stimulate microbial activity and biochemical
transformation, which subsequently increase the
biodegradation and biosorption potential. This process is
often referred to as plant assisted bioremediation.
Development of new economically feasible eco-friendly
products from natural plants / agricultural wastes is the
objective of my continued research in Central Institute of
Brackishwater Aquaculture, Chennai, India. In this
direction, attempts have been made to develop products for
the decontamination of toxicants in the laboratory
condition. Further work is in progress to explore the
possibility of the use of these plant products for
the remediation of shrimp farm culture water in the ponds
/ wastewater in the water reuse system. Natural plant
products are biodegradable and cause no harm to the
environment. Hence the natural plant products may offer a
selective, harmonious and eco-friendly approach to remove
nitrogenous toxicants and successful studies on this
material could be beneficial for shrimp farm wastewater
treatment.
Phytoremediation
Applications for Arsenic in Northern Climates
Michael
J. Blaylock, Edenspace Systems Corporation, 15100
Enterprise Court, Suite 100, Dulles, VA 20151, Tel:
703-961-8700, Fax: 703-961-8939, Email:
blaylock@edenspace.com
Mark P. Elless, Edenspace Systems Corporation, 15100
Enterprise Court, Suite 100,
Dulles, VA 20151, Tel: 703-961-8700, Fax: 703-961-8939,
Email: elless@edenspace.com
Charissa Y. Poynton, Edenspace Systems Corporation, 15100
Enterprise Court, Suite 100,
Dulles, VA 20151, Tel: 703-961-8700, Fax: 703-961-8939,
Email: cyp@edenspace.com
More
than 70% of the United States arsenic consumption,
representing approximately 37 million pounds of arsenic
per year, is used to produce chromated copper arsenate (CCA),
a wood preservative. Weathered lumber in decks, docks,
playground equipment and garden construction can leach
significant amounts of arsenic into soil and water, where
it poses health risks to humans and animals. In addition
to CCA sources, arsenic was used extensively
as a component of many pesticides used in
agriculture. Phytoremediation techniques using an arsenic-hyperaccumulating
fern (Pteris vittata) has been developed as a
cost-effective remediation alternative for soils
containing elevated arsenic concentrations. One of the key
factors in phytoremediation of arsenic is achieving
sufficient biomass production by the fern crop to result
in significant arsenic removal rates. Pteris vittata,
a subtropical species that is perennial in Zones 9 and
higher, has been effectively used as a summer annual in
northern climates for phytoremediation. However, increased
costs from annual replanting combined with reductions in
biomass yields with shorter growing seasons reduces the
cost-effectiveness at some sites.
Recently,
several cold-hardy species in the Pteris genus have been
identified that also hyperaccumulate arsenic. Expanding
the perennial climate range will provide significant
improvements in phytoremediation performance. Growth
chamber and field studies were conducted to evaluate the
potential performance of these plants with existing
arsenic hyperaccumulators for both biomass yield and
arsenic uptake. Additonal cultural practices designed to
extend the growing season were also investigated. The
anticipated result of this research is an improved
phytoremediation approach that is applicable to many of
the arsenic-contaminated soils in northern climates. The
results of these and other studies will be presented.
Can
We Predict the Best Plants for the Phytoremediation of
Organic Contaminants?
Chris
D. Collins, Imperial College, Exhibition Rd., South
Kensington, London, SW7 2BP, Tel (+44) 207 594 7378,
Email: c.collins@imperial.ac.uk
Neil J. Willey, University of the West of
England, Frenchay, Bristol, BS16 1QY, Tel: (+44) 117-965
6261, Email: Neil.Willey@uwe.ac.uk
There
is a continuing interest in the clean-up of contaminated
sites by biological means, because of the improvements in
sustainability that they offer.
One potential tool in this strategy is
phytoremediation. To date there have been a number of
studies which have indicated that certain plant orders
have the ability to accumulate heavy metals. In one study
three orders; the Malpighales, Brassicales and Asterales
were found to contain c.85% of the hyperaccumulating taxa.
These taxonomic approaches can provide important
information when choosing appropriate plant species for a
given contaminant and ecological situation. Furthermore
such approaches will become more useful as plant
classification becomes more informed by genetic
information, as this is more likely to provide information
on a species’ ability to produce enzymes or chelators
which may be important in metal accumulation or organic
pollutant degradation.
The paper will present our initial findings when
using phylogentic screening approaches for those plants
which may be beneficial for the phytoremediation of
organic pollutants.
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