Assessment of concentration level of some heavy metals and non -metallic ions in dumpsite soils in the Federal Capital Territory, Nigeria

Abstract

The concentration of heavy metals (Fe, Cd, Cr, Cu, Pb, Mn, Ni and Zn), pH and non-metallic ions (Cl^-, NO₃^- and SO₄^2-) in soil samples from dumpsites and soil samples from areas without dumpsites (control) in the study area were determined at depth 0-15cm, 45-60cm and 85-100cm.The digestion of samples was done using concentrated nitric acid. The Atomic Absorption Spectrophotometer (AAS) and titration methods were used to determine heavy metals and non-metallic ions respectively. At depth 0-15cm, heavy metal concentration in the dumpsite soil in both seasons were; Fe (19.8911 and 21.8488 mg/g), Cd (0.0012 and 0.0017 mg/g), Cr (0.7610 and 0.2285 mg/g), Cu (0.3657 and 0.1259 mg/g), Pb (0.5063 and 0.9991 mg/g), Mn (6.3547 and 3.446 mg/g), Ni (0.2549 and 0.1247 mg/g), Zn (1.2057 and 3.2462 mg/g). In both seasons control Fe (18.0275 and 14.5668 mg/g), Cd (0.0078 and 0.0000 mg/g), Cr (0.1768 and 0.2643 mg/g), Cu (0.0308 and 0.0528 mg/g), Pb (0.0201 and 0.3776 mg/g), Mn (0.0824 and 0.1163 mg/g), Ni (0.0256 and 0.0000 mg/g), Zn (0.0695 and 0.8055 mg/g). Heavy metal contents for soil samples across the profile depth at 0-15cm, 45-60cm and 85-100cm were also significantly higher at P<0.05 from top down wards as well as between soil and control. Assessed parameters for dumpsite soil samples at depth 0-15cm, 45-60cm and 85-100cm all exceeded the WHO international standards in both seasons. It is therefore concluded that the waste dumpsites have negative impact on the quality of soil the study area. As such, there is need for government to overhaul her approach towards management of waste dumpsites and also to develop better waste management practices with regard to municipal solid waste management to mitigate soil pollution and its attendant implications in the FCT.

Keywords: Soil Pollution, Waste dumpsite, Municipal Solid Waste Management, Sustainable Development