Bioaccumulation and Bioconcentration of Pb in the Tissues of Eight Weed Species

Abstract

Lead (Pb) is a toxic heavy metal that is ubiquitous in our environment. Exposure to Pb is a threat not only to humans and other organisms but to the entire environment as well. This study assessed the Pb-bioaccumulation and bioconcentration abilities of eight plant species in Pb-contaminated sites. Atomic Absorption Spectroscopy (AAS) results indicated that higher Pb concentrations were determined in the root tissues of plants compared with the shoot tissues. Species with high amount of Pb in root tissues were Mimosa pudica (1495.45 ppm), Centrosema pufescens (1149.1 ppm), Eleusine indica (916.65 ppm), Panicum antidotale R.(756.35 ppm), Cyperus rotundus (534.4 ppm), Cynodon dactylon (516.35) and Dichantium sericeum (397.55 ppm). More so, C. dactylon accumulated the highest shoot Pb (8.05 ppm), followed by M. pudica (4.4 ppm), D. sericeum (4.3 ppm), C. pufescens (2.15 ppm), P. antidotale (2.15 ppm), E. indica (3.3 ppm) and R. communis (1.95 ppm). Among these species, C. pufescens had the highest bioconcentration factor (BCF) and thus, can efficiently bioconcentrate Pb. These results revealed the ability of these eight species to bioaccumulate Pb in their tissues. Finally, plant species that can efficiently concentrate Pb from the soil into the root and shoot tissues are the promising species for phytoremediation of Pbcontaminated sites.