Assessing the Effect of a Dumpsite on Groundwater Quality: A Case Study of Aduramigba Estate within Osogbo Metropolis

Abstract

This research assessed the impact of an open dumpsite, on the quality of groundwater within the vicinity of Aduuramigba Estate. Twenty water samples were collected and analyzed for physic-chemical parameters, major ions and trace metal using AAS, Iron Chromatographic and titrimetric methods.

The result showed that almost all the physico chemical parameters such as pH (7.5-10.8), temperature (27.4^oC-31.5^oC,) EC (70µS/cm-364 µS/cm), TDS (49-248mg/l) fall within limits as recommended by WHO and NSDWQ. Chemical parameters has the following results: Cl^- (122-720mg/l), SO₄^2- (0-7.41mg/l), NO₃^-(0.64-1.64mg/l), HCO₃^- (12.20-91.5mg/l), Ca²⁺ (3.95-65.12mg/l), mg²⁺ (0.73-17.28mg/l), Fe²⁺ (0-1.36mg/l), Na⁺ (3.45-27.37mg/l), k⁺ (1.04-24.41mg/l) Mn²⁺ (0-0.57mg/l). All major ions revealed concentration within the acceptable limit of both standards except Chloride and Sodium in some of the wells, this is due to the addition of a disinfectant named Sodium Dichloroisocyanurate (C₃N₃O₃CL₂Na) commonly called water guard and weathering of feldspars which characterized the basement rocks underlying the area. Most of the trace metals tested for were below detectable limit of the AAS except Zinc, Iron and Manganese. Iron and Zinc concentrations fall well within the acceptable limit of both WHO and NSDWQ standards while Manganese concentration were above the limit in most of the surface and shallow groundwater at the down slope of the Dumpsite. This could be attributed to the impact of the leachates from the waste and because of the persistent nature of manganese within the medium, it may not be easily attenuated.

Keywords: Leachates, dumpsite, groundwater, conductivity, basement rocks.