Phytoaccumulation of Heavy Metals in Natural Vegetation at the Municipal Wastewater Site in Abbottabad, Pakistan

Abstract

Heavy metal accumulation in crops and soils from wastewater irrigation poses a significant threat to the human health. A study was carried out to investigate the removal potential of heavy metals (HM) by native plant species, namely Cannabis sativa L., Chenopodium album L., Datura stramonium L., Sonchus asper L., Amaranthus viridus L., Oenothera rosea (LHer), Xanthium stramonium L., Polygonum macalosa L., Nasturtium officinale L. and Conyza canadensis L. growing at the municipal wastewater site in Abbottabad city, Pakistan. The HM concentrations varied among plants depending on the species. Metal concentrations across species varied in the order iron (Fe) > zinc (Zn) > chromium (Cr) > nickel (Ni) > cadmium (Cd). Majority of the species accumulated more HM in roots than shoots. Among species, the concentrations (both in roots and shoots) were in the order C. sativa > C. album > X. stramonium > C. canadensis > A. viridus > N. officinale > P. macalosa > D. stramonium > S. asper > O. rosea. No species was identified as a hyperaccumulator. All species exhibited a translocation factor (TF) less than 1. Species like C. sativa, C. album and X. stramonium gave higher (> 1) biological concentration factor (BCF) and biological accumulation coefficient (BAC) especially for Fe, Cr and Cd than other species. Higher accumulation of heavy metals in these plant species signifies the general application of these species for phytostabilization and phytoextraction of HM from polluted soils.