Heavy metal bioaccumulation by selected plants from fly ash–contaminated soils in suburban area

Abstract

In fly ash–contaminated soils, metal buildup and translocation and their subsequent uptake in different parts of naturally growing plants were studied. The mean metal levels in soil and plants at uncontaminated site were significantly (p Fe> Cr > Zn > Pb > Cu > Ni > Mn. The shoot enrichment factor (SEF) of Pithecellobium dulce (P. dulce) was Cd > Fe > Zn > Cr > Ni > Cu > Mn > Pb, whereas for Azadirachta indica (A. Indica) and Cassia fistula (C. fistula), the SEF was of the order Fe > Cd > Cr > Zn> Ni > Mn > Cu > Pb, respectively. Root enrichment factor (REF) for P. dulce was Cd > Fe > Zn > Ni > Cu > Cr = Mn > Pb, but in A. indica, the REF was Fe > Cd > Zn > Ni > Mn > Pb > Cu > Cr, and in C. fistula, this order was Fe > Cd > Zn > Ni > Cr > Cu > Mn > Pb. Metal mobilization ratio in plants at both sites were below 1, except Mn and Fe at contaminated site. Single and combined element pollution indexes (SEPI and CPI) and shoot contamination factor (SCF) at contaminated soil were higher than uncontaminated, but root contamination factor (RCF) between sites shows a variable response. From ANOVA results, metal concentration showed significant variation due to site, plants, location, and season interactions.