Pedo and biogeochemical study of Zinc-Lead deposits of the Besham area,northern Pakistan: its implication in mineral exploration and environmental degradation

The distribution of Zn, Pb, Cu, Cr, Ni and Co in the plant species and soil of the Zn-Pb sulfide deposits of the Besham area in Pakistan has been studied for geochemical prospecting and environmental pollution. Representative samples of several plant species and associated soil were collected and analyzed by the atomic absorption technique. The data suggest that the plants, especially Plectranthus rugosus, Artemisia indica and Verbascum thapsus, in the mineralized area are enriched in Zn, Pb and Cu (Zn>Pb>Cu) and depleted in Cr, Ni and Co. This is correlated with the concentration of these metals in the associated soil. There is no significant correlation of elements among each other in plants and soil; however, strong correlation of Cu, Cr and Ni has been observed between plants and associate soil. Plectranthus rugosus has the greatest capability for accumulating Zn and Pb in its tissues through soil and can be used as a bioindicator for base metal mineral exploration. This plant along with other plant species such as Artemisia indica and Verbascum thapsus having high scavenging ability for Zn and Pb from the soil and could cause serious environmental and health problems in the living organisms of the area.