Heavy metal contamination of groundwater resources in a Nigerian urban settlement

Abstract

The aim of the study was to create awareness on the effect of dumpsite on groundwater in developing countries, especially Nigeria. In order to achieve this, water samples were obtained from 20 randomly selected hand dug wells and boreholes in the area, in February and August, 2006. 10 leachates samples were also obtained from the dumpsite. From these samples, pH and conductivity were determined using a pH/conductivity meter (Jenway model), while the concentrations of the heavy metals (Co, Fe, Pb and Cu) were determined using atomic absorption spectrophotometer (AAS). The trend of dispersion of each variable was demonstrated on Landsat ETM+ (2006) imagery using Erdas Imagine and ArcView GIS software. The study showed that the groundwater in the study area were generally alkaline (8.3 ± 2.77) and contained Cu (0.02 ± 0.04 mg/l), Fe (4.23 ± 6.4 mg/l), Pb (2.4 ± 3.3 mg/l) and Co (1.03 ± 1.1 mg/l) concentrations that are higher than the permissible limits recommended by the World Health Organization (0.5, 0.1, 0.01 and 0.0002 mg/l, respectively; p > 0.05). The study concluded that the groundwater sources within 2 km radius of a major landfill will be vulnerable to the effect of landfill, if they are not adequately protected. Key words: Groundwater, landfill, Landsat imageries, heavy metals contamination