Cadmium, copper, lead and zinc accumulation in wild plant species near a lead smelter.

Abstract

Smelting activities have been shown to increase the likelihood of environmental heavy metal accumulation and bioaccumulation potential within relative proximity to smelter sites. This investigation focused specifically on cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) accumulation in 43 wild plant species and corresponding soils near a Pb smelting contaminated area. Soils in the study area had elevated Cd, Cu, Pb and Zn concentrations, with pollution indices ranked as Cd>Pb>Cu>Zn. Aboveground plant heavy metal concentrations ranked Pb>Zn>Cd>Cu, with plants having greater bioconcentration factor (BCF) values for Cd than for Pb, Cu and Zn. Plant Cd BCF averaged 1.42, while Pb, Cu and Zn averaged 0.128, 0.256 and 0.560, respectively. The greatest Cd BCF value was 5.40 for Dendranthema indicum; Cd accumulation for this species has not been reported previously. The greatest shoot Cd concentration (66.5mgkg-1) was found in Viola verecunda. Significant correlations existed between plant shoot Cd and Pb concentrations and soil total and DTPA-extractable Cd and Pb. Plant species with greater heavy metal accumulation could potentially be used for phytoextraction in the study area, while those having less accumulation potentially being used to reduce heavy metal flow into the food chain, reducing the health risks associated with elevated heavy metal soil contamination.