Heavy Metals Distribution in Soil at Different Depths and Radiuses around Landfills in Districts of Nyékonakpoè, Akodesséwa and Amoutivé in Lomé City

Abstract

This study aims to provide baseline data about soil contamination by some heavy metals at different depths around landfills in areas at high risk of groundwater contamination. Soil samples were taken in three replicates at depth of 0 – 20 cm, 20 – 40 cm and 40 - 60 cm in the radiuses of 0 to 10 m, 10 to 20 m and 20 to 30 m around landfills. In all, 81 homogenized composite soil samples were collected. The heavy metals were measured in soil samples by atomic absorption spectrophotometer. The results show that the concentration of mercury (0.03 – 0.29 mg kg-1), cadmium (0.04 – 0.69 mg kg-1), arsenic (0.05 – 2.30 mg kg-1) and nickel (0.05 – 2.35 mg kg-1) in analyzed soil samples were lower than the limit values set by WHO, Finland and Dutch environment ministries. However, lead concentrations (90.15 – 129.14 mg kg-1) in topsoil in vicinity of landfills in Amoutivé and Akodesséwa were above reference values set by WHO, Finland and Dutch environment ministries. As the heavy metals may be leached to reach groundwater, the landfills management must be great concern to municipal authorities. The frequent monitoring of the quality of soil and groundwater will be necessary to follow the level environmental contamination by heavy metals around landfills and the possible initiate remedial measures.