Groundwater quality evaluation: a case study of Igando waste dumpsite, southwestern Nigeria

Applied Water Science (2022) 12:79 https://doi.org/10.1007/s13201-022-01601-x ORIGINAL ARTICLE Groundwater quality evaluation: a case study of Igando waste dumpsite, southwestern Nigeria Olusegun O. Ige1 · Adebowale T. Owolabi2 · Oluwaseun F. Olabode3 · Daniel O. Obasaju4 Received: 27 June 2020 / Accepted: 18 February 2022 / Published online: 21 March 2022 © The Author(s) 2022 Abstract The quality of groundwater samples around Igando area, Lagos State, Nigeria was investigated with the aim of detecting possible influence of dumpsites on nearby aquifers. Thirty-seven (37) groundwater samples were evaluated for their suitability in drinking and agricultural purposes. Physical parameters were determined in situ using portable multi-meter. Flame absorption was used to determine the concentrations of major cations while ion chromatography and titrimetry was used for anions’ concentration. Bacteriological test was conducted using multiple tube technique. Results of in-situ physical parameters revealed pH range of 7.01–7.79, EC range of 20–880 μS/cm while TDS range from 13–590 mg/L. Laboratory analyses showed C a2+ concentration ranging 1.60–72.80 mg/L and H CO3− ranging 19.52–204.96 mg/L as the dominant ions. None of the ions’ concentrations exceed the WHO drinking limit. Water Quality Index (WQI) classification showed that all samples fall within good to excellent water categories. The majority of the samples are suitable for irrigation using indices such as Sodium Adsorption Ratio (SAR), Kelly’s ratio (KR), and Magnesium Hazard (MH). Bacteriological analyses revealed low total bacterial count and E-coli absence making the samples safe for drinking. Piper diagram indicated two main water-facies (Ca–HCO3 and the Mixed Ca–Mg–Cl). Gibbs’s plots showed that the samples are primarily influenced by rock weathering, while precipitation also contributed. Chloro-Alkaline Index confirmed direct ion-exchange process. Cluster analyses revealed four groups: the first revealed influence of groundwater by anthropogenic activities in the study area, the second and third revealed lithological origin of ions in the water while group 4 indicated pH low influence on the dissolved ions in the waters. The groundwater quality can be said to be fair-good, thus suggestive of minimal interactions between the dumpsites and the groundwater in the area at the time of testing. Keywords Groundwater · Quality · WHO · SAR · KR · Piper · Water-facies Introduction Life expectancy is largely dependent on the potability of water available for drinking and agriculture (Oloruntola et al., 2018; Ige et al., 2020, 2021). However, increasing population, urbanization and industrialization are major * Daniel O. Obasaju 1 Department of Geology and Mineral Sciences, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria 2 Department of Geology, University of Ibadan, Ibadan, Nigeria 3 Department of Geology, Federal University of Technology Akure, Akure, Nigeria 4 Department of Earth Sciences, Kogi State University, Anyigba, Nigeria threats to harnessing good quality water. This is because waste generated from these symbols of societal deveploment consistute environmental nuisance, especially to water, soil and the air (Fig. 1). It is very common to find open dumpistes within and around major/capital cities in Nigeria with heterogeneous type of wastes. The waste will be chemically broken down in the presence of water to form leachate. Leachates are organic in nature but might carry some chemical constituents whose activities have negative effects on the engineering properties of underlying soil. The groundwater system suffers the major negative impact of leachate through the introduction of heavy metals (Pb, Cd, Fe, Zn etc.), dissolved minerals (Na, Mg, K, salts), suspended particles (clay, silt, sand) and development of leachate plumes (Mepaiyeda et al., 2019). Although unengineered landfills are synonymous to groundwater pollution, the potential and degree of pollution most times rest largely on the properties 13 Vol.:(0123456789) 79 Page 2 of 14 Applied Water Science (2022) 12:79 Fig. 1  sampling locations around the dumpsite of saturated zone, atteneuation capacity and amount of precipitation (seasonal effect). In Lagos Nigeria, Igando (“Solous”) I–III (Fig. 1), Abule Egba and Oloshosun are the major dumpsites that are approved by the government for operation. However, the operations are not without environmental impacts. Several environmental studies (Ayolabi et al, 2013; Odukoya et al., 2013) have been carried out around “Solous” dumpsite in Igando to monitor its impacts on soil, water and air. Impacts of solid waste dumpsite were evaluated at “Solous” dumpsite III, Lagos state by Olorode and Alao (2013b, a) using VES and VLF methods. Results revealed the presence of porous sandy unit extending beyond 20 m below the base of landfill and that leachate has laterally moved about 300 m away from the dumpsite. Coker et al (2019) assessed the impact of solid waste on groundwater quality in “Olusosun” dumpsite, Lagos, Nigeria. A combined geophysical and geochemical methods was carried out at the dumpsite. Results of ten Vertical Electrical Sounding (VES) and five 2D electrical traverses revealed vertical percolation of leachate beyond 40 m in the southeastern direction. The flow direction was a serious concern because of the high population density of humans impacted negatively by the leachate migration. Elevated concentration of some heavy metals above World Health Organisation (WHO) maximum permissible limits were recorded. Salami and Susu (2019) conducted a comprehensive study of leachate characteristics 13 from three “Solous” Dumpsites in Igando Area of Lagos State, Nigeria. This work was carried out with a view of establishing correlation matrix for the leachate parameters in each of the dumpsites. Aside from values of biological oxygen demand (BOD) and chemical oxygen demand (COD) which are higher than the recommended standards, the correlation matrices showed a strong relationship among the parameters and it was therefore recommended that the practice of waste dumping in unengineered open spaces should be discouraged. Aderemi et al. (2011) evaluated degree of groundwater contamination by leachate near open dumpsite in Abule Egba, Lagos. Concentrations of physical and chemical parameters of samples of water within and around the site were measured. Results from the analysis showed minimal impact of leachate from the landfill on groundwater body due to natural attenuation property of the clayey unit in the stratigraphic setting. The focus of this paper is to assess physicochemical parameters of groundwater in the vicinity of waste dumpsites in Igando area to monitor negative impact on the quality and make appropriate recommendation for usability. This shall be achieved by examining effects of distance from dumpsite on the properties of groundwater, determining and isolating regions of pollution, (...truncated)