Assessment of heavy metal pollution in soil and their implications within and around mechanic villages|
Nwachukwu, M. A.; Feng, H. & Alinnor, J.
Analysis of nine composite soil samples, each made of three replicate core samples and their respective
background samples collected from Okigwe, Nekede and Orji automobile mechanic villages were conducted. Metal
concentrations (mg/kg) above the background levels in the top 100 cm soil profile ranges as follows: 748-70,606 (±
10114.3) for iron; 99-1090 ± 251.3 for lead; 186-600 ± 180 for manganese; 102-1001± 201.9 for copper; 8-23 ± 12.9 for
cadmium; 4-27 ± 6.0 for chromium; and 3-10 ± 2.2 for nickel. The order of abundance is: iron > lead > manganese > copper > cadmium > chromium > nickel, with Okigwe > Nekede > Orji. Pollution indexes show that the metals have
similar pollution trends in the three layers (L1-L3), with L1 (0-10 cm) > L2 (10-20 cm) > L3 (90-100 cm) in Okigwe, L3
>L1>L2 in Nekede, and L3 >L2 >L1 in Orji. In effect, the shaly Okigwe soil is more polluted in the top layer while the
sandy Nekede and Orji are more polluted in the lower layers. Despite this order, metal bioavailability may be less in the
Okigwe soil due to its high clay-silt content (47 %-64 %). Pollution factor for Okigwe is 0.8, Nekede is 0.7 and Orji is
0.5. Nekede is under severe to excessive pollution while Orji and Okigwe are under moderate to excessive pollution, with
weathered depths 7.4m at Orji and Nekede and 4m at Okigwe as most implicated in the pollution process. Above
provides the bases for introducing the innovative concepts of environmentally friendly mechanic village.
Automobile wastes; Environmentally friendly mechanic village; Pollution factor; Pollution index