SSRG International Journal of Geoinformatics and Geological Science (SSRG-IJGGS) – Volume 6 Issue 2–May – Aug 2019 Assessing Groundwater Quality In Katsina State, Nigeria A. S. Oyewumi,G. K. James, I.M. Jega, O.O. Olojo, J.T. Shar, H. Onuoha, V.T. Salami, S. Mustafa, I. Shehu, A. N. Waziri, M. M. Mahmood and K.S. Salman Hazards and Environmental Management Division, Strategic Space Applications Department, National Space Research and Development Agency(NASRDA) Abuja, FCT, Nigeria. ABSTRACT some 40 percent of the planet‟s irrigated agriculture[1]. Groundwater in comparison with Groundwater quality is crucialto the determination surface water has long been regarded as the pure of the water’s suitability for drinking, domestic, form of water. This is as a resultof purification of agricultural and industrial purposes. The the former in the soil column through anaerobic suitability of groundwater for the different intents decomposition, filtration and ion exchange. depends on its intrinsic quality. Secondary data of Consequently causing the excessive consumption some groundwater samples from seventy borehole of groundwater in rural and semi-urban areas all locations across Katsina State was obtained from over the world [2]. the state’s Rural Water Supply and Sanitation Agency (RUWASA). Elevenphysico- Groundwater quality is crucial to the determination chemicalparameters (pH, total dissolved solids of the water‟s suitability for drinking, domestic, (TDS), total hardness (TH), electrical conductivity agricultural and industrial purposes. The suitability (EC), chloride, iron, manganese, sulphate, total of groundwater for the different intents depends alkalinity, fluoride and nitrate) of the samples from upon its intrinsic quality which reflects inputs from borehole locations were used to compute Water the atmosphere, soil and rock weathering, as well Quality Index (WQI) with a view to assessing the as from anthropogenic activities [3]. The value of suitability of the groundwater for human groundwater does not only lie in its widespread consumption. The results show WQI values for the occurrence and availability but also in its consistent entire Katsina State range from 18.05 to 60.76, good quality [4], [5]. Groundwater is degraded representing excellent and good water quality. when its quality parameters are altered beyond their Samples from twenty-nine Local Government Areas natural variations by the introduction or removal of (LGAs) have average WQI values lower than 50 certain substances [6], [7]. Once pollution enters thereby representing excellent water quality while the subsurface environment, it is has been samples from the remaining five LGAs have WQI estimated that it may remain concealed for many values greater than 50 thereby representing good years, and in no time get dispersed over wide areas water quality. The results show about 85% of of groundwater aquifer and rendering groundwater groundwater in Katsina State has excellent water supplies unsuitable for consumption and other uses quality while the remaining 15% have good water [8]. Again, once the groundwater is contaminated, quality. its quality cannot be restored by stopping the pollutants from the source. It is therefore essential Keywords: Groundwater, Water Quality Index, to routinely monitor the quality of groundwater and Drinking Water, Excellent Quality Water to chart ways and means to protect it [9].Groundwater must therefore be meticulously I. INTRODUCTION managed to maintain its purity within standard Groundwater has increasingly been the major limits being a fragile and important source of source of fresh water in many parts of the world in drinking water, [2]. recent times. Its usage spans through domestic, industrial water supply and irrigation all over the Water quality index (WQI), a technique for rating world. Groundwater accounts for more than a third water quality is an effective tool to assess spatial of municipal and industrial supply and services and temporal changes in groundwater quality and ISSN: 2393 - 9206 www.internationaljournalssrg.org Page 45 SSRG International Journal of Geoinformatics and Geological Science (SSRG-IJGGS) – Volume 6 Issue 2–May – Aug 2019 communicate information on the quality of water to have the considerable impact on water quality, the concerned citizens and policy makers [10], are recommended [19]. [11]. WQI is defined as a rating reflecting the 2. Determination of Quality Function (curve) composite influence of different water quality for Each Parameter Considered as the Sub- parameters, which is calculated from the point of Index: Sub-indices transform to non- view of the suitability of groundwater for human dimensional scale values from the variables of consumption [10]. WQI has been successfully its different units (ppm, saturation percentage, applied to assess the quality of groundwater in the counts/volume etc.). recent years as it serves in the understanding of water quality issues by integrating complex data 3. Sub-Indices Aggregation with and generating a score that describes water quality Mathematical Expression: This is status. Basically, WQI aims at giving a single value frequently utilized through arithmetic or of water quality of a source reducing great number geometric averages. of parameters into a simpler expression and enabling easy interpretation of monitoring data Several number of water quality indices have been [12]. formulated by different national and international With the use of secondary data of some organizations and these have been applied for the groundwater samples from 70 borehole locations assessment of water quality in particular areas. obtained from the Rural Water Supply and Examples include Weight Arithmetic Water Sanitation Agency (RUWASA), Katsina State, this Quality Index (WAWQI), National Sanitation work attempts to compute WQI with a view to Foundation Water Quality Index (NSFWQI), assessing the groundwater suitabilityfor human Canadian Council of Ministers of the Environment consumption. Water Quality Index (CCMEWQI), Oregon Water Quality Index (OWQI) and Scottish Water Quality II. WATER QUALITY INDEX Index (SWQI) [20], [21].A number of researchers across the globe developed WQI models based on Horton (1965)[13] initially developed WQI in the weighing and rating of different water quality United States by choosing 10 most commonly used parameters [22], [23]. Most water quality indices water quality variables such as dissolved oxygen rely on normalizing, or standardizing, data (DO), pH, coliforms, specific conductance, parameter by parameter according to expected alkalinity and chloride. This has been widely concentrations and some interpretation of „good‟ applied and accepted in European, African and versus „bad‟ concentrations. Parameters are often Asian countries [14]. The assigned weight reflected then weighted according to their perceived significance of a parameter for a particular use and importance to overall water quality and the index is has considerable impact on the index. Following calculated as the weighted average of all this, a new WQI similar to Horton‟s index was observations of interest (e.g., [25]-[29]. developed by the group of Brown in 1970. This There is no globally accepted composite index of was based on weights to individual parameter [15]. water quality, the UNEP GEMS/Water programme In recent times, many adjustments have been put up has however selected the Canadian Water Quality for WQI concept through various scientists and (CWQI aka CCMEWQI) as the model to follow in experts[16], [17]. A general WQI approach [18] is developing the global water quality index. This based on the most common factors, which are model was selected as it requires the use of a described in the following three steps: benchmark or guideline which allowed for comparison of values to the World Health 1. Parameter Selection: This is carried out by Organisation‟s Drinking Water Quality Guidelines. judgment of professional experts, agencies or To assess the robustness of these guidelines, government institutions that is determined in the comparisons with drinking water quality guidelines legislative area. The selection of the variables was conducted with those currently in place in the from the 5 classes namely oxygen level, European Union, Australia and USA. In line with eutrophication, health aspects, physical the use of the aforementioned guidelines, many characteristics and dissolved substances, which researchers and agencies however adopt the local ISSN: 2393 - 9206 www.internationaljournalssrg.org Page 46 SSRG International Journal of Geoinformatics and Geological Science (SSRG-IJGGS) – Volume 6 Issue 2–May – Aug 2019 (national) standards for the development of the The highest amount of evaporation occurs during water quality index. the dry season. Two major rivers namely; River Gada and Karadua III. MATERIALS AND METHODOLGY dominate other few perennial rivers and streams in Study Area the State. The study is focused on Katsina State. The These rivers flow over the basement complex, thus state is located between latitude 11º 08' North and are characterized by rapids and falls. They flow 13º 22' North and longitude 6º 52' East and 9º 20' into the Rima and Sokoto Rivers which ultimately East. Katsina State was created in 1987 from the drains into the Niger River [32]. Above the defunct Kaduna State. It spans a total area of basement complex rocks of the State predominantly 2 approximately 23,983 km . The state is bounded in are ferruginous tropical red and brown soils.