Abstract

This study aims at assessing heavy metal contamination in Bangote, Gbafou and Nguesse soils around Bengote Open Cast Mining in Cameroon. In soil samples, heavy metals namely Iron (Fe), Chromium (Cr), Vanadium (V), Nickel (Ni), Copper (Cu), Mercury (Hg), Zinc (Zn), Lead (Pb), Arsenic (As), and radioactive elements Thorium (Th) and Uranium (U), contents were determined using ICP-MS techniques. The heavy metals average concentration in Upper Continental Crust (UCC) was considered background value. Average concentrations of heavy metals in both soils mixed with mining spoil lie above that of the world soil. Pb, V, As and U contents exceed the critical limit value of WHO specified standard.

The mean concentration of Cr, V, Ni, Cu, As, Hg, Pb, Th and U in studied soils are 245.00, 370.00, 8.27, 60, 90, 172.00, 0.18, 3640.00, 28.30, and 4.95mg/kg, respectively. The Enrichment Factor (EF), Contamination Factor (CF), Geoaccumulation Index (Igeo), Pollution Load Index (PLI) are the indices used to assess the contamination risk. The enrichment factor of all the studied metals for all sampling sites are in descending order Pb >V> Cr > As > Cu > Th > U> Ni > Cd. The contamination factor values revealed that Pb and V highly impacted the studied soils. The Pollution Load Index (PLI) values of most samples are >1, indicating the progressive deterioration of soils due to their contamination.

Keywords:Heavy metal; Contamination; Bengote; Pollution; Soil

Nomenclature:Fe: Iron; Cr: Chrome; V: Vanadium; Ni: Nickel; Cu: Copper; Hg: Mercury; Pb: Lead or Sinker; Th: Thorium; U: Uranium; WHO: World Health Organization; km2: Kilometer square; m: Meter; mm/year: Millimeter/year; cm: Centimeter; kg: Kilogram; mm: Millimeter; Log : Logarithm; mg/kg: Milligram/kilogram