Assessment of effects of a Cemetery leachate on Groundwater Quality using an Integrated Approach

Abstract

The dependency of residents in the vicinity of cemeteries on groundwater from hand-dug wells as an alternative source of water supply for their domestic use without cognisance of the quality of such water has been a concern. So, this research assesses the effects of a cemetery on groundwater quality using an integrated approach in Edunabon, South-western Nigeria. Thirty groundwater samples from available hand-dug wells were collected and analysed for various physicochemical parameters. GIS cloud data collection server and Mobile Data Collector (MDC) were used to obtain these hand-dug wells' locations and spatial distributions. The determination in variation in physicochemical concentration parameters was obtained using the curve fitting technique of ARCVIEW GIS software and digital map. Physicochemical results were used to calculate Water Quality Index (WQI) of each sample. Two Schlumberger Vertical Electrical Soundings (VES) of 130.0m long were conducted at 10.0m intervals to the wall and the next VES, on each side of the cemetery. Current spacing (AB/2) and apparent resistivity (ρa) data were plotted on a double logarithm paper, curved matched and iterated using IPI2Win software for qualitative and quantitative interpretation. WQI results ranged from (107.37–173.64), (76.60–93.37), (54.94–71.53), (31.29–48.01), and (10.84–25.31) for fourteen, seven, three, four and two hand-dug wells respectively, an indication that the water from these wells was unfit for drinking, very poor, poor, good, and excellent respectively. VES results revealed that first, second and third layers were mainly clayey topsoil (46.7–96.8Ωm), lateritic soil (169.0–551.3Ωm), and weathered layer (3.21–27.4Ωm), which favourably enhances the migration of leachate from the cemetery to the surrounding soils and groundwater. The lowest resistivity values recorded in the second and third layers indicated leachate presence at these hand-dug wells. The integration of GIS and electrical resistivity methods would be useful tools to assess groundwater quality around cemeteries. Keywords: Groundwater quality, Mobile Data Collection, unfit for drinking, Vertical Electrical Sounding, Water Quality index