Municipal waste dumpsite: Impact on soil properties and heavy metal concentrations, Sunyani, Ghana

The use of soils around dumpsites in rural and urban areas in Ghana is common for food production especially vegetables. However, most people use such soils without knowledge of the risk of heavy metal uptake by plants. Therefore, the evaluation of heavy metal contamination is an important component of risk assessment at waste dumpsites. Hence, this study was conducted in Sunyani municipality to determine the risk of heavy metal pollution and physicochemical properties of soils at a waste dumpsite. Fifteen (15) soil samples (5 from each zone) were collected from a depth of 0–30 cm depth within the 3 demarcated zones of the dumpsite namely; Top-site, Dump-site, and Down-site. Physicochemical properties and heavy metals (e.g. lead, zinc and cadmium) were analysed to determine their concentrations in the collected soil samples. From the result, significant differences (p < 0.05) in soil chemical properties were observed and their levels ranked as dump-site > down-site > top-site. The concentration of the metals ranked as Fe > Pb > As > Zn > Cd at the dumpsite. The results revealed that the soil at the dumpsite is heavily contaminated with Fe (> 30 mgkg−1) as opposed to less than 0.55 mg kg−1 for the remaining heavy metals (As, Cd, Pb and Zn). However, heavy metals contamination at the various sampling locations of the dumpsite were within the permissible limits recommended by FAO/WHO. There is the need for regular monitoring and decontamination of the dumpsite before use for agricultural activities.