Phytoremediation of Pb Spiked Soils Amended with Iron Impregnated Rice Husk Ash Using Ricinus communis L. (Castor bean)

Abstract

Heavy metals pose a serious risk to the environment and living biota. Pot studies were carried out to determine the competence of Fe-coated rice husk in Pb spiked soils vegetated with Ricinus communis. Physicochemical properties of Fe- coated rice husk ash (Fe-RHA) were characterized on dry weight basis. Pot experiments were carried out with seedlings of R.communis for 60 days amended with Fe-RHA (0, 2.5% and 5% w/w) and Pb(NO3) [0, 400 and 800 mg kg−1]. Addition of Fe-coated rice husk ash to Pb cntaminated soils improved soil pH and fertility. Treatment with 5% Fe-RHA decreased Pb accumulation in roots by 84%. Addition of FeRHA significantly (p<0.05) increased plant physiological parameters such as height, leaf diameter, nodes, and leaf number by 64%, 49%, 62% and 66% and chlorophyll contents (12–29%) compared to unamended plants. Our findings conclude that Fe-RHA is a low-cost, environmentally friendly and efficient adsorbent for stabilization of Pb spiked soils.