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.
