A study of physico-chemical properties and heavy metals in contaminated soils of municipal waste dumpsites at Allahabad, India

ABSTRACT The study assesses the qualities of contaminated soils of three municipal waste dumpsites in Allahabad, Uttar Pradesh. The pH of the dumpsite soils ranged from 6.42±0.46 to 7.16±0.81 which is tending towards neutral or alkaline pH. Water holding capacity and moisture content at dumpsites were in good amounts (30.43±1.33 to 48.58±1.19 and 35.53±1.79 to 50.77±1.32 % respectively). Organic matter was higher (1.60±0.39 to 2.55±0.48%) at dumpsites as compared to their adjoining areas. Clay texture class played a significant role in differentiating normal soils of adjoining area than dumpsite soils. Total metal concentrations of Cr, Cu, Fe, Ni, Pb and Zn were also analyzed and elevated levels of heavy metals were obtained at dumpsites (32.46±1.07 to 108.85±3.99 mg/kg). Metal contamination at dumpsite was in the order of Pb>Zn>Fe>Ni>Cu>Cr>Cd imparting highest contamination to Daraganj dumpsite while Phaphamau dumpsite was least contaminated. Cr and Cd were not detectable from all adjoining areas while Pb, Zn, Fe, Ni and Cu were present in least amounts (7.32±0.30 to 37.94±4.22 mg/kg). Physico-chemical properties and heavy metal concentrations at each dumpsite were also correlated with each other and many significant correlations were observed. Concentrations of Zn were highly correlated with the concentrations of Cu, Ni and Pb (r =-0.66 to 0.86, p<0.05). Concentrations of Cr were also significantly correlated with Ni and Pb (r =-0.62,-0.69, p<0.05). The study evidently indicates that the level of heavy metal contamination is higher at dumpsites which may be a cause of concern for their surrounding environment and organisms. This work will prove valuable in providing baseline information for further soil quality monitoring studies in study area