Assessment of Heavy Metal Concentrations of Municipal Open-Air Dumpsite: A Case Study of Gosa Dumpsite, Abuja

Heavy metals are among the major components of municipal solid wastes with a high atomic weight and a minimum density five times that of water. These metals pose serious environmental and health problems. This study was conducted to determine the concentrations of selected heavy metals- Lead (Pb), Cadmium (Cd), Copper (Cu), Zinc (Zn) and Manganese (Mn)- in a solid waste site, Gosa dumpsite, Abuja. These heavy metals were studied during the 2019 dry season using Atomic Absorption Spectroscopy. Six soil samples were collected from six different points from the main dumpsite. Soil samples were digested and the physicochemical parameters such as particle size, pH, Cation exchange capacity, exchangeable cations and analysis of the soils were carried out using standard procedures. The results revealed variations in the physicochemical parameters in the different study points. Notably, there was a high level of Pb (1.382 ± 1.223 mg/l), Cd (0.257 ± 0.022 mg/l) and Mn (0.615 ± 1.347 mg/l) which exceeded the WHO (Pb: 0.010 mg/l, Cd: 0.001 mg/l and Mn: 0.050 mg/l) and SON (Pb: 0.010 mg/l, Cd: 0.003 mg/l and Mn: 0.200 mg/l) limits for agricultural and industrial soils. However, Cu and Zn were within WHO and SON permissible limits. These results were similar in the soil samples obtained from the main dumpsite and the nearby study points within the Gosa village. The high levels of Pb, Cd and Mn may be attributed to the transfer and infiltration of leachate from the dissolved materials in solid waste from the dumpsite.