Screening of pearl millet for phytoextraction potential in soil contaminated with cadmium and lead

Abstract

ABSTRACT Pot experiments were designed to assess the potential of pearl millet (Pennisetum glaucum) in the phytoextraction of cadmium (Cd) and lead (Pb) from contaminated soil. A moderately contaminated clayey loam was loaded singly with 0 -150 mg kg -1 of Cd and Pb, followed by ethylenediaminetetraacetic acid (EDTA) and/or poultry manure treatments. Pearl millet was grown and observed weekly for changes in height, leaf breadth; and post-harvest shoot wet/dry biomass and Cd/Pb concentrations. Growth profiles were essentially sigmoid with growth rates appearing to decelerate with metal dose. Based on the potting media, growth rates and millet biomass followed the order: soil-metal-manure > soil-metal-EDTA-manure > soilmetal > soil-metal-EDTA and were less in Cd-than Pb-loaded soils. Tissue metal concentrations in the various potting media were: soil-metal (22.2 -83.5 mg Cd/kg; 16.2 -63.5 mg Pb/kg); soil-metal-EDTA (46.5 -105.2 mg Cd/kg; 35.3 -86.6 mg Pb/kg); soil-metal-manure (4.6 -38.2 mg Cd/kg; 5.0 -25.6 mg Pb/kg); soil-metal-EDTA-manure (6.3 -45.7 mg Cd/kg; 6.0 -35.2 mg Pb/kg). Soil-to-millet transfer factors, f (%) showed that cadmium (8.8 ≤ f(%) ≤ 89.1) was more phytoavailable to millet than Pb (5.0 ≤ f(%) ≤ 59.4). The findings may be useful in the phytoremediation of soils moderately contaminated by Cd and Pb