Introduction to Phytoremediation - CLU-IN

the paper. Tables and graphs in the reviewed literature
provide quantitative information on plant uptake. Experiments
conducted on plant uptake of hexachlorobenzene,
phenol, toluene, and TCE are described in depth.
Burken, J. G., and J. L. Schnoor. 1997. Uptake and Metabolism
of Atrazine by Poplar Trees. Environ. Sci. Technol.
31:1399-1406.
This presentation describes poplar trees grown in soil or
sand that took up, hydrolyzed, and dealkylated radiolabeled
atrazine to less-toxic compounds. Metabolism was
found to occur in roots, stems, and leaves, and the
amount of metabolism increased with increased time in
plant tissue. In leaves, the atrazine parent compound
was found to be 21% of the radiolabel at 50 days, and
10% at 80 days. In the sand planting, uptake of the radiolabel
was 27.8% at 52 days and 29.2% at 80 days.
Less than 20% of radiolabel remained as bound residue
in plant tissue. Atrazine degradation in unplanted soil
was similar to degradation in planted soil. A model for
atrazine metabolism was also presented.
McCutcheon, S. 1996. Phytoremediation of Organic Compounds:
Science Validation and Field Testing. In W. W.
Kovalick and R. Olexsey (eds.), Workshop on
Phytoremediation of Organic Wastes, December 17-19,
1996, Ft. Worth, TX. An EPA unpublished meeting summary.
An overview of the uses, advantages, and disadvantages
of phytoremediation are presented along with the identification
and use of plant-derived enzymes for
photodegradation. Field demonstrations at several Army
Ammunition Plants are also discussed.
Newman, L. A., S. E. Strand, N. Choe, J. Duffy, G. Ekuan,
M. Ruszaj, B. B. Shurtleff, J. Wilmoth, P. Heilman, and M.
P. Gordon. 1997a. Uptake and Biotransformation of Trichloroethylene
by Hybrid Poplars. Environ. Sci. Technol.
31:1062-1067.
Discussions are presented of axenic poplar tumor cell
cultures dosed with TCE and samples that were analyzed
for degradation products and 14 CO 2 . The cells studied
metabolized TCE to trichloroethanol and di- and
trichloracetic acid. The cell cultures oxidized 1 to 2% of
the TCE to CO 2 in 4 days. Whole trees were exposed to
50 ppm TCE. Leaves were bagged and the entrapped
air sampled for TCE. Plant parts were harvested and
analyzed for TCE and metabolites. TCE-exposed trees
had significant TCE in stems but minimal amounts in
leaves. Equal concentrations of trichloroethanol and TCE
were found in leaves, but a smaller concentration of
trichloroethanol than TCE was found in stems. Trichloroacetic
acid appeared in stems and leaves. Roots contained
TCE, trichloroacetic acid, dichloroacetic acid, and
trichloroethanol. TCE was transpired from the trees.
Paterson, S., D. Mackay, D. Tam, and W. Y. Shiu. 1990.
Uptake of Organic Chemicals by Plants: A Review of Pro-
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cesses, Correlations and Models. Chemosphere. 21:297-
331.
The routes of entry (root uptake and foliar uptake) of
organic compounds into plants are discussed. Equations
are presented that correlate the concentration in various
parts of a plant to the octanol-water partition coefficient,
molecular weight, or Henry’s Law constant. A review
of plant uptake models is also included. Crossedreferenced
tables are included that identify the literature
citations for plant uptake research conducted on different
plant species and on different chemical compounds.
Thompson, P. L., L. A. Ramer, and J. L. Schnoor. 1998.
Uptake and Transformation of TNT by Hybrid Poplar Trees.
Environ. Sci. Technol. 32:975-980.
In these laboratory experiments, hybrid poplars and radiolabeled
TNT were used in hydroponic and soil systems.
Much of the TNT was bound in the roots, with relative
little (