Accumulation of heavy metals in autochthonous plants around Bagega Artisanal Gold Mining Village and the remediation potential of selected plants

Abstract

The research was conducted to evaluate the accumulation potential of some heavy metals in autochthonous plants around Bagega mining sites and to test their remediation potential. Soil sample and 16 different plant species were collected at four mining and gold processing sites. The content of heavy metals in the soil and different parts of the plants were determined using atomic absorption spectroscopy (AAS). The soil's Pb content was 1021 ± 198.8 mg kg1, while the Cd, Cr, and Zn contents were 14.17 ± 0.5239 mg kg1, 9.74 ± 1.855 mg kg1, and 185 ± 6.45 mg kg1, respectively. Azadirachta indica, Calatropis procera, and Eucalyptus camaldulensis were selected out of the collected plants based on their high Pb hyperaccumulation levels for phytoremediation analysis. An experiment per species was designed with three replicates in a completely randomized design. The grown plants were subjected to AAS analysis, and the accumulation of the studied metals was in the order Zn < Pb < Cd < Cr, with the highest accumulation of Pb from the contaminated soil of 68 ± 5 mg kg1 in the root of C. procera. There was a significant difference (p < 0.005) in the absorption of all tested metals between contaminated and control sites. The enrichment coefficient and bioaccumulation factor were <1. All plants accumulate >100 times the Pb, Cd, and Cr content of plants from uncontaminated environments. The three plant species could be useful for remediating heavy metals in contaminated soil.