Spatial Distribution of Heavy Metals in Soil and Flora Associated with the Glass Industry in North Central India: Implications for Phytoremediation

Abstract

The effect of the glass industry on soil metal characterization was assessed at five test sites at five successive distances in a semi-arid area. A comprehensive profile of Zn, Cd, Pb, Ni, Cu, and As levels in soils was obtained. The spatial distribution patterns of integrated contamination indices for these metals show a similar decreasing trend in distribution as we move further from the industrial cluster. There was significant correlation among individual heavy metal concentrations in the soil samples. Integrated contamination indices indicate that 64% of the sites were in the high contamination range and 28% were in the moderate contamination range. A statistically significant difference (P ≤ 0.001) was obtained for each metal on comparing mean metal content among soil samples. Phytoremedial potential of 12 native plant species was also evaluated. Individual elements displayed remarkably different patterns of accumulation in soils as well as plants. Plants established limited capabilities in mobilizing Zn, Pb, Ni, and Cu in the root zone. While Cd, Cu, As, Zn and Pb were predominantly partitioned in shoots, Ni was equally partitioned between shoots and roots. Interestingly, some plants showed a different partitioning trend at higher concentrations of different metals compared to lower concentrations. Potential species for phytoremediation include Calotropis procera (Milk weed), Chenopodium murale (Goosefoot),Poa annua (Annual bluegrass) and Datura stramonium (Thorn apple). None of the species showed phytoremedial potential for Ni and Cu.