Assessment of Groundwater Quality in a Typical Rural Settlement in Southwest Nigeria

M Adetunji,I Adekunle,O Banjoko,A Gbadebo

doi:10.3390/ijerph200704040007

Abstract

In most rural settlements in Nigeria, access to clean and potable water is a great challenge, resulting in water borne diseases. The aim of this study was to assess the levels of some physical, chemical, biochemical and microbial water quality parameters in twelve hand - dug wells in a typical rural area (Igbora) of southwest region of the country. Seasonal variations and proximity to pollution sources (municipal waste dumps and defecation sites) were also examined. Parameters were determined using standard procedures. All parameters were detected up to 200 m from pollution source and most of them increased in concentration during the rainy season over the dry periods, pointing to infiltrations from storm water. Coliform population, Pb, NO3- and Cd in most cases, exceeded the World Health Organization recommended thresholds for potable water. Effect of distance from pollution sources was more pronounced on fecal and total coliform counts, which decreased with increasing distance from waste dumps. The qualities of the well water samples were therefore not suitable for human consumption without adequate treatment. Regular monitoring of groundwater quality, abolishment of unhealthy waste disposal practices and introduction of modern techniques are recommended.

Highlights

Nigeria is located in West Africa and has variable terrain
Water quality parameters analyzed in accordance to standard methods of [9] were pH, temperature, conductivity, total solids (TS), total suspended solids (TSS), total dissolved solids (TDS), turbidity, nitrate (NO3-), sulphate (SO42-), phosphate (PO43-), copper (Cu), lead (Pb), cadmium (Cd), dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), fecal coliform (FC) and total coliform (TC) counts
Seasonal variation from dry to rainy periods increased the concentrations of Cu, Pb, fecal coliform, total coliform, BOD, COD, electrical conductivity, total dissolved solids in most cases

Summary

Introduction

Nigeria is located in West Africa and has variable terrain. The climate ranges from equatorial in the south to tropical in the centre and arid in the north. Climatic variations influence the vegetations, ranging from mangrove swamps in the south, tropical rainforest in the centre, savannah in the north and sahel savannah in the north - east. The annual rainfall varies from 4000 mm in the south and 250 mm in the north with a national average of 1180 mm [1]. Geological reports gave rock types as Precambrian basement in the southwest, south-east and north-central. The rocks include gneisses, schists, migmatites, pegmatite, charnockitic and quartz-schist [2,3,4]

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