Monitoring of Heavy Metals In Soil Surroundings Solidwaste Dumpsites

Abstract

The study aimed at the monitoring of heavy metals in soil surroundings solid waste dumpsites including I-14 dumpsite, Bhatta dumpsite and NUST. Soil samples were collected at three different depths i.e. (1-10 cm, 10-30 cm, 30-50 cm) from each solid waste dumpsite down the slope. The samples were analyzed for presence and concentration of Cd, Fe, Mn, Cr and Zn by using XRF and atomic absorption spectroscopy. Results showed that the accumulation pattern for the heavy metals in the soil profile follows the order Fe>Cr>Zn>Mn>Cd. The mean concentrations of Iron in surface soils in all three dump sites was 9.38 % while in 2nd depth 9.56 % and in 3rd depth the 9.48 %. While the mean concentration of Mn in surface soils were lies in 7.5 to 14.1 mg/kg while in 2nd Depth were in the range of 8 to 12.4 mg/kg and in 3rd Depth the values were lies 8.1 to 10.8 mg/kg. The mean values of Cd in all the dump sites and reference soil were in the range of 1.7 to 2.5 mg/kg while 2nd depth Cd values were in the range of 1.6 to 2.6 mg/kg and in 3rd depth 1.7 to 3.3 mg/kg. Similarly in surface soil Zn values were 115 to 242.7 mg/kg while in 2nd depth 104.9 to 210.5mg/kg and in 3rd depth 99.1 to 299 mg/kg were obtained and the mean concentrations of Cr in surface soils in all three dump sites were 72.2 to 132.8 mg/kg while in 2nd depth 45.3 to 134 mg/kg and in 3rd depth the values were 40 to 178.5 mg/kg. The concentrations of heavy metals found in the sites were below the threshold limits defined by USEPA (2001). While the levels found in these dumpsites were higher than the reference soil levels. Higher accumulations of these heavy metals were obtained in surface soil and within the depth concentration of heavy metals were xiv decreased. Statistically, the examined metals showed non-linear correlation with soil physicochemical properties which is suggestive that these metals arise from anthropogenic activities and may be the other parameters like hydrology and porosity are involved.