Study of Heavy Metal Uptake by Different Plant Species for Phytoremediation.

Contamination of soils by lead (Pb) could be a result of agricultural practices and industrial activities. The use of plants has been proposed as a cheap, sustainable, effective and environment friendly alternative to conventional technologies for phytoremediation. Pb accumulates at the surface layers of the soil where it binds to organic materials. Soil particle size and cation exchange capacity as well as plant factors will affect the availability and uptake of Pb by plants. Therefore, in our present investigation we compare the remedial capacity of three different plant species by analyzing the accumulation of lead in the plant shoot system. The three plants used in this study were Indian mustard (Brassica juncea), Morning glory (Ipomoea sps), and Bermuda grass (Cynodon dactylon). The experiment was conducted under control conditions in the greenhouse facility at MVSU. The plants were grown in replicates of 4 pots, consisting of 3 treatment groups; control (water), 0.05M nitric acid (NA) and 20ppm Pb + 0.05M NA solution. Two weeks after germination, five treatments of final concentration of 20ppm of lead and 0.05M NA was applied to the pots. The results from the shoots tissue analysis did not show any significant amount of Pb accumulation in either plant; however it altered the concentration of other minerals in the shoots. An increase in Ca concentration was observed in all nitric acid and Pb treated plants, whereas, Fe, Zn, and Cu significantly decreased in the above treatments. S and Mn also concentration increased in morning glory. Since we did not find increased concentration of Pb in the shoots of treated plants as expected, we conclude that further investigation is required.