STUDY OF METAL UPTAKE AND PLANT GROWTH ON LIVE ALFALFA PLANTS GROWN
IN SOLID MEDIA
1
J.R. Peralta, 1K.J. Tiemann, 1S. Arteaga, 1E. Rascon, 1J.G. Parsons, 1E. Gomez, and 2J.L. GardeaTorresdey
1,2
Department of Chemistry and Environmental Science and Engineering, University of Texas at El
Paso, El Paso, TX 79968; 2Phone: (915) 747-5359, E-mail: jgardea@utep.edu.
Heavy metals contamination is a troublesome environmental problem in many industrial countries,
and phytoremediation technologies are promising solutions to clean a variety of pollutants.
Preliminary studies have shown that live alfalfa plants (Medicago sativa) can survive in heavy
metal-contaminated soils. Therefore, we decided to study the metal uptake abilities of live alfalfa
plants using solid media. The objective of this study was to determine the effects of Cd(II), Cr(III),
Cu(II), Ni(II), and Zn(II) on seed germination and plant growth in alfalfa. The heavy metal
concentrations in the growth media varied from 0, 10, 20, and 40 ppm for each metal ion studied.
Following two weeks of growth, germination rate, root, and shoot length were recorded along with
the metal content. Results of these experiments indicate that Cd(II) concentrations reduced the shoot
growth by 54%, 70%, and 100%, respectively. The results for the other metal ions studied also
reduced growth respective to the increasing metal content by the following amounts: Cr(III) 31%,
54%, and 93%; Cu(II) 12%, 37%, and 67%; Ni(II) 17%, 30%, and 63%. However, the presence of
Zn(II) enhanced the growth of plants and it overpassed the control length by 4% with the doses of 10
and 20 ppm. The doses of 20 and 40 ppm of Cd(II), Cr(III), and Cu(II) affected the germination rate
by more than 40%. These results indicate the feasibility of using live alfalfa plants in the
remediation of moderately, heavy metal-contaminated soils.
Key words: phytoremediation, alfalfa, Medicago sativa, solid media