Modeling Lateral Distribution of Heavy Metal and Bio-accumulation in Earthworm in the Varying Acidic Surface Horizon of Waste- Polluted Soil (original) (raw)

2013, International Journal of Energy Engineering

Heavy metal concentrations and its distributions in the soil have been a source of concern to soil usage, particularly to agriculture as concentration and distribution of heavy metal determine to a large extent, the soil quality and consequently that of the crops. The ability to quantify the amount of heavy metal in the soil is of immense importance to soil management. The use of accurate model is essential to estimate the actual soil heavy metal values and its distribution for efficient management. In this study, soil and earthworm samples of the battery-waste-polluted site and that of the background site were collected fro m five different locations(A,B,C,D and E) along the gradient of decreasing pollution .With five replicates each form one sampling location, twenty-five soil and fifty earthworms samples (two earthworms fro m each replicate) were collected using stratified random sampling technique. Lead(pb), Cad miu m(Cd), Chro miu m(Cr), Nickel(Ni), Manganese(Mn), Arsenic(As), pH and Mercury(Hg) were analy zed using standard methods. The same process was replicated for the background site. Values of the heavy metals in soil and earthworms were natural and typical of A meki-Nanka-soil formation. The average range of heavy metals concentrations in soil and earthworm samples fro m the polluted site were; pb(1025-695 mg/kg), Cd(11.34-6.3 mg/ kg), Mn(290-81 mg/kg), p H(2.3-6.9mg/kg), Cr(185-3.7 mg/ kg), Ni(12.87-1.7 mg/kg), As(72-4.5 mg/kg), Hg(1.7-0.002mg/kg) and pb(193-37.98 mg/kg), Cd(14.04-0.01 mg/ kg), Mn(17.34-1.10mg/ kg), p H(6.9-2.3mg/kg), Cr(8.45-0.01 mg/kg), Ni(1.41-0.03 mg/ kg), As(0.75-0.01 mg/kg) , Hg(0.4-0.009mg/ kg) respectively. Concentrations of heavy metals for soil and earthworm samples decreased along the gradient of decreasing pollution of the polluted site. Three models(Linear , Logarith mic and quadratic models) were developed to test their suitability to the data in which Ph was correlated with heavy metals. Inverse correlation was observed with coefficient R2 of between 0.77-0.95 and lowest percentage deviation of the field fro m the predicted values.