Journal of Geography, Environment and Earth Science International 11(1): 1-15, 2017; Article no.JGEESI.34634 ISSN: 2454-7352 Mapping Groundwater Quality Parameters Using Geographic Information System (GIS) in Oyo State, Nigeria T. O. Ogunbode 1* and I. P. Ifabiyi 2 1Faculty of Basic Medical and Health Sciences, Bowen University, Iwo, Nigeria. 2Department of Geography and Environmental Management, University of Ilorin, Nigeria. Authors’ contributions This work was carried out in collaboration between both authors. Both authors read and approved the final manuscript. Article Information DOI: 10.9734/JGEESI/2017/34634 Editor(s): (1) Wen-Cheng Liu, Department of Civil and Disaster Prevention Engineering, National United University, Taiwan and Taiwan Typhoon and Flood Research Institute, National United University, Taipei, Taiwan. Reviewers: (1) H. O. Nwankwoala, University of Port Harcourt, Nigeria. (2) Dorota Porowska, University of Warsaw, Poland. Complete Peer review History: http://www.sciencedomain.org/review-history/20122 Received 2nd June 2017 th Original Research Article Accepted 9 July 2017 Published 19 th July 2017 ABSTRACT The knowledge of spatial pattern of groundwater quality is important to ensure a holistic approach to the management of the resource quality status in space and time. Thus a sample each of underground water was collected from each of the selected 5 rural communities in each of the selected 25 out of the 33 LGAs in Oyo State for the purpose of quality assessments. Eleven (11) + parameters namely water temperature (°C), pH, electr ical conductivity (EC), Sodium (Na ), SO 4, + Potassium (K ), Nitrate (NO 3), Phosphate (PO 3), coli-form count, Oxidation Redox Potential (ORP) and Total Dissolved Solids (TDS) were subjected to standard laboratory analysis. The data was further subjected to analysis of variance and Duncan post-hoc test. ArcGIS version 10.1software was applied to generate maps to show the Duncan groupings of each of the quality parameters across the study area. Two (2) parameters namely pH and sulphate show homogenous distribution while the other nine (9) parameters are heterogeneous. Descriptive analysis showed that the groundwater in the study area is generally fit for human consumption. However, adequate attention needs to be given to temperature and potassium contents because they both slightly exceeded the _____________________________________________________________________________________________________ *Corresponding author: E-mail: [email protected]; Ogunbode and Ifabiyi; JGEESI, 11(1): 1-15, 2017; Article no.JGEESI.34634 standard required. The mapping affords spatial understanding of the distributional pattern of the parameters so that appropriate water quality management measure/s can be taken at a minimised cost to ensure appropriate levels of the parameter in the water to safeguard human health. Repeated investigation is required to determine the regularity or otherwise pattern of the water quality parameters. Keywords: GIS; mapping; Oyo State; water quality; water management. 1. INTRODUCTION infiltration before it replenishes or added to the antecedent groundwater. Mapping spatial phenomena is salient to the understanding of geographic studies. Several However, constant awareness of the status of attempts have been made to map spatial water is salient to human welfare as such will phenomena in geography and in other related reveal the resource potability at a point in time disciplines. For instance [1,2,3,4] carried out and in space. According to [14,7,15], the use of water poverty mapping in their areas of study, Geographic Information System (GIS) has grown the works that enable better understanding of rapidly in groundwater management and is now spatial water scarcity with less stress while [5] widely used to create digital geographic integrated water quality index with geographic databases, to manipulate and prepare data as information system (GIS) for an effective input for various model parameters and to interpretation of the quality status of a river. display model output. The application of GIS as a Mapping enables the location and fast tool has afforded the understanding of the spatial understanding of other attributes of spatial variation of ground water quality parameters. The phenomena. Mapping of water quality objectives of this study are to assess the quality characteristics is still inadequate in water of groundwater; to determine its spatial pattern in resource management as most of the existing the rural areas of Oyo State and to map the works focus on the contents of quality quality with the application of GIS technique. parameters and at times its implications for human health having compared with the 2. STUDY AREA acceptable standards. However, a holistic understanding of water quality over space will Oyo state, located on latitude 07°N to 09°N and help resource managers in taking holistic steps longitude 02.80°E and 4.50°E, has its to either mitigate excessive occurrence of a headquarters at Ibadan. It is bounded in the parameter and/or widening the scope of our North by Kwara State, in the east by Osun State, understanding of the status of water over an in the South by Ogun State and in the West area [6,7]. Spatial mapping of water quality partly by Ogun State and partly by the Republic parameters enables affordable cost of ensuring of Benin (Fig. 1). the water resource management to enhance human health [8]. Examples of research in the Oyo State covers approximately an area of areas of mapping water quality parameters be it 28,454 km 2 and is ranked fourteenth by size in surface or subsurface water resources include the country. It has thirty-three (33) Local [9,10,11]. In the view of [9], groundwater is Goververnment Areas (LGAs). The total believed to be comparatively much clean and population as at 2006 census was 5,591,589 free from pollution than surface water. This view [16]. Some of the major urban centres include is in agreement with the observations of [12] and Ibadan, Ogbomoso, Oyo, Iseyin, Saki, Okeho [13] where it was revealed that exploitation of among others. underground water for domestic purposes is prominent in developing countries because of the The State is endowed with two seasons namely susceptibility of surface sources to pollutants and dry and wet seasons. Dry season starts from also as a result of its fair quality. It was also November to March while wet season starts from emphasized that groundwater is less open to March and ends in October. Rainfall amount pollutants and when even contaminated water is varies from an average of 1200 mm around introduced to the surface of the earth, it Igbeti in the northern part of the State to 1800 undergoes natural treatment in the course of mm in Igbo-Ora and Ibarapa zone in the 2 Ogunbode and Ifabiyi; JGEESI, 11(1): 1-15, 2017; Article no.JGEESI.34634 Fig. 1. Map of Oyo State showing some of the rural communities investigated southern part. Water supply situation in Oyo networks often, as an alternative, resorted to state according to [17] is below any acceptable subsurface sources through digging of wells and standard. The records from the Water boreholes. It is worth noted that despite fair and Corporation, as revealed in the work, indicated better status of underground sources, cases of that 233,485 m3 is generated daily by all water total abandonment of some wells or segrigation supply schemes in the state out of which about of some wells for certain purposes, according to 55,080 m3 is actually supplied daily. The record [19], have been observed, the scenario being further revealed that only 17.45% of households attributed to the physical, chemical and biological have piped water supply, but in Ibadan constituents of such underground sources. municipality 55% of households are linked to piped water supply. Thus over 56% of 3. HYDROLOGEOLOGY households in Oyo State have to obtain their water from unreliable sources. A report by [18] Rocks of basement complex found in Oyo State showed that preventable diseases are common. include schists, associated with quartzite. The For example, schistosomiasis increased from 25 metamorphic rocks are largely undifferentiated, reported cases in 2003 to 1107 in 2005, cholera but two specific rock groups may still be increased from 157 in 2004 to 2768 in 2005 and identified [20,21]. The first group consists of typhoid from 484 in 2003 to 10,432 in 2005. Due migmatite complex, including banded magmatic to the susceptibility of surface water resources to and augen gneisses and pematites. contaminants [13], inhabitants in the rural areas Metasediments consisting of schists and who are hardly connected to pipe borne water quartzites, calsilicates, met conglomerates, 3 Ogunbode and Ifabiyi; JGEESI, 11(1): 1-15, 2017; Article no.JGEESI.34634 amphibolites and metamorphic iron beds make from the selected five (5) villages in each of the up the second group (Fig. 2). Other parts of the twenty five (25) out of the thirty three (33) local State are underlain by undifferentiated government areas in the State for the purpose of metamorphic rocks. water quality analysis (see Table 1). Samples were collected in a 2-litre plastic container which The structural features that are important in had been treated with 10 percent concentrated hydrogeological thinking are difficult to elucidate nitric acid for 48 hours to rid off every in certain areas owing to the obliterating effect contaminants. These were labelled appropriately of migmatization [20,22]. According to [20], and sealed to avoid contamination before aquifers are of restricted vertical and lateral laboratory tests. The parameters that needed to extent, but since the tropical climate affords the be determined in-situ were taken especially necessary conditions for deep and rapid water temperature, pH and electrical conductiviy. chemical decay, thick, sandy clayey, lateritic The analysis was carried out in the Departments overburdens serve as potential aquifers. of Chemistry and and that of Food Science and Prediction of potential aquifers is possible Technology, Bowen University, Iwo, Nigeria.