The use of some weeds type in the disposal of heavy metals in contaminated soil

Abstract

Heavy metals have much concern for communities with overpopulations due to their lack of biodegradability, which becomes contaminated to agricultural soil and agricultural products. This research employed Polyogon monospeliensis and Phalaris minor for cleanup Pb, Cd, and Co metals in farmland soils to assess their biological properties as natural accumulators. The total uptake by weed biomass ranged from 0.23 to16.86 (Pb), 0.11 to 9.31 (Cd) and 0.18 to 9.76 (Co) µg kg -1 for P. minor and 0.38 to 29.29 (Pb), 0.14 to 0.19.22 (Cd) and 0.23 to 20.76 (Co) µg kg−1 for P. monospensis respectively. These findings suggest that the concentration of heavy metals steadily increased in weed biomass with increasing pollution of the soil. The metals accumulation by weeds has a varied response to the weed species, metal type and the used concentration. The ordered sequence of tested metals remediation was ranked as follows; Pb > Cd > Co for metals. Based on bioconcentration factor (BCF) and contamination index (Ci), P. monospensis is a hyper-accumulator with appropriate growth and P. minor is a medium accumulator with negatively affected growth in a higher concentration of metals. The spreading of these weeds is widely in the winter of Egypt, thus they could be used to remediate polluted soil and protect the ecosystem with good efficiency.