Assessment of the Levels of Heavy Metal Contamination in Soils Around Selected Municipal Solid Waste Dumpsites in Benin City, Nigeria using Pollution Indices

Authors: Otabor KE, Oviawe AP, Ilori EG

DOI Info: N/A

ABSTRACT

Contamination levels assessment of heavy metals such as Cu, Pb, Mn, Ni, Zn, Cd and Cr in soils around municipal solid waste dumpsites in Benin City, Edo State, Nigeria was carried out. The aforementioned metals were analytically determined with an atomic absorption spectrophotometer. The mean concentration levels of heavy metals in the studied dumpsites ranged from 7.63 ± 0.06 to 37.27 ± 0.06 mg/kg for Cu, 1.23 ± 0.21 to 8.30 ± 0.01mg/kg for Pb, 1.30 ± 0.26 to 9.27 ± 0.31mg/kg for Mn, 1.00 ± 0.00 to 5.13 ±0.06 mg/kg for Ni, 5.00 ± 0.17 to 37.93 ± 0.87 mg/kg for Zn, 1.00 ± 0.00 to 6.79 ± 0.02 mg/kg for Cd, and 0.91 ± 0.01 to 5.60 ± 0.36 mg/kg for Cr. Zn was found to be more abundant and was closely followed by Cu while Cr was least abundant in the studied sites. The contamination and pollution index (C/PI) of the analysed heavy metals showed that only Cd was in the pollution ranges with high risk degree while other analysed heavy metals were in the contamination ranges with low risk degree as indicated by the C/PI and the potential ecological risk index (PE_i^R) respectively. The pollution load index (PLI) ranges and mean levels were in the following order: Dumpsite II (1.41 – 6.1) averaging 3.41 > dumpsite I (1.85 – 3.82) averaging 2.76 > dumpsite III (1.08 – 2.92) with an average of 1.95, which represents the number of times the metal content in the soil exceeds the average natural background concentration.

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