Evaluating Land Use Effects on Groundwater Quality in Lagos-Nigeria Using Water Quality Index

Abstract

The study relates groundwater quality to land use types in Lagos State. Fourteen samples were collected from hand dug wells and boreholes, seven each from rural and urban land uses in the study area. Ten parameters (pH, electrical conductivity, total dissolved solids, total hardness, calcium, magnesium, chloride, nitrate and sulfate) were determined using standard methods. The resulting water quality indices revealed that 58.09% of the samples were rated very poor while 21.73%, 9.08% and 11.1% were rated poor, good and excellent, respectively in rural land use. The analysis of samples drawn from urban land use revealed that 76.55% of the water was unfit for drinking while 14.4%, 6.42% and 2.63% were found to be very poor, good and excellent, respectively. pH, total dissolved solids, chloride, total hardness and nitrate were beyond the permissible limits for urban land use while, pH, total hardness and nitrate were above permissible limits for rural land use. These parameters were found to be responsible for the poor water quality rating in the study areas. The paper recommends a comprehensive effective sewerage system for safe disposal of sewage, efficient waste water handling and control of urban runoff to prevent groundwater quality deterioration in the study areas.Keywords: Evaluation; Groundwater; Quality; Land use; Water quality index; Lagos-Nigeria.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i2.7142 J. Sci. Res. 4 (2), 397-409 (2012)