Download corroboration of copper and chromium uptake by creosote bush

CORROBORATION OF COPPER AND CHROMIUM UPTAKE BY CREOSOTE BUSH USING
HYDROPONICS: SPECTROSCOPIC STUDIES
1
S.Arteaga, 1R.R. Chianelli, 2J.L. Gardea-Torresdey, 3W.P. Mackay, and 4N.E. Pingitore
1,2
Departments of Chemistry and Environmental Science and Engineering, University of Texas at El
Paso, El Paso, TX 79968; 3Department of Biology, University of Texas at El Paso, El Paso, TX
79968; 4Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968;
2
Phone (915) 747-5359, 2E-mail: [email protected].
Phytoremediation has developed as a potential remediation solution for contaminated sites. Also,
phytoremediation takes advantage of the fact that plants may extract and concentrate particular
elements from the environment. Creosote bush, or Larrea tridentata, is a common desert shrub of
the Southwest, covering roughly 20 million acres from western Texas to California. This plant is
found growing naturally in heavy metal-contaminated soils in the El Paso area. Previous
investigations had found that this plant is able to accumulate and concentrate high amounts of
copper and other metals from soils in its tissues. For this reason, this plant is considered to be a
"hyperaccumulator." Creosote bush seedlings were exposed to two different concentrations of
copper sulfate (63.5 ppm and 635 ppm) during 48 hours using hydroponics. Another set of plants
were exposed to K2Cr2O7 (520 ppm Cr+6) and Cr(NO3)3 (520 ppm Cr+3) for the same period of
time. The roots, stems, and leaves of the plants were analyzed by atomic absorption spectroscopy
giving positive copper and chromium uptake results. The different parts of the plants were
analyzed using X-ray absorption spectroscopy. Also, the copper and chromium laden plant's tissues
were analyzed with X-ray microfluorescence. Results of our experiments will be presented. We are
currently performing experiments for the uptake of Cr+6 and Cr+3 by living creosote bush seedlings.
The results of those experiments will also be presented.
Key words: phytoremediation, soil contamination, creosote bush, XAS, XRMF