Continental J. Environmental Sciences 4: 1-11, 2010 ISSN: Wilolud Journals, 2010

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1 Continental J. Environmental Sciences 4: 1-11, 2010 ISSN: Wilolud Journals, SPATIAL VARIATION IN GROUNDWATER QUALITY OF JOS METROPOLIS AND ENVIRONS, NORTH- CENTRAL NIGERIA. Aga, T. 1, Beka, N.C. 2 and Eziashi, A.C. 3 1 Department of Geology and Mining, University of Jos, Nigeria, 2 National Environmental Standards and Regulations Enforcement Agency, Jos, Nigeria, 3 Department of Geography and Planning, University of Jos, Nigeria. ABSTRACT Groundwater occurrence within Jos Metropolis and environs in Central Nigeria has been investigated for its quality, from which inferences are drawn on the factors or processes controlling the quality of the groundwater and the general variability of water quality in the Metropolis. The results indicate a chemical property of low ph, high TDS and high nitrates at the center of the study area. Concentration values of cationic elements are Ca 2+, Mg 2+ have values ranging from 1.56 to 38.6 and 0.85 to respectively. Concentration values of Fe(T), Cu 2+, Mn 2+ range from 0.0 to 1.17, 0.0 to 0.35, 0.0 to 0.6 respectively. Anions comprising NO -3, SO 4 2-, Cl - have respective concentration values ranging from 0.44 to 181, 0.00 to 25, 0.75 to The bacteriological constituents of the water samples include Faecal Coliform and Total Coliform ranging from 0 to 30 cfu and 0 to 36 cfu respectively. In many ways the spatial distribution of these quality parameters seems to carry signatures of poor sanitation. Factor analysis indicate that the geologic factor which is Factor 1 is controlling the quality of the groundwater in the Metropolis but also reveals that human activities which was delineated as Factor 2 measures very closely after the geology. KEYWORDS: spatial variation, physicochemical, bacteriological, groundwater, Jos) INTRODUCTION The study area is located within the Jos metropolis and is bounded by latitudes 10º 00 and 9º 50 and longitudes 9º 00 and 8º 55 (Figure 1). This study area covers parts of four local government areas namely Jos north, Jos south and Jos east, and Bassa local government areas of Plateau State, Nigeria. The study area covers an area of about 340 km 2, extending for about 18 km from north to south, and 18.5 km from east to west. The area is accessible through a major road passing from Toro and Zaria road in the north; it passes through Jos metropolis and heads towards Buruku at the southern end. The relief of the area shows a lot of relationship with its geology. The southern part of the area is made up of the Younger and Older Granites being resistant rock types constitute the upland areas, rising to an average height of m with Naraguta and Shere hills reaching 1,400 m and 1,780 m respectively. The Basement rocks form the low-lying area at the northern part of the study area with areas like the Neil s valley at the north eastern part. The area bears the general climatic characteristics of Jos-Plateau which is controlled by its altitude and its position across the seasonal migration of the inter-tropical convergence Zone (ITCZ), with annual rainfall of 1,371 mm spanning over 7 months (Eziashi, 1995), also atmospheric temperature of o C which supports the grass savanna vegetation in the study area. The study area is covered roughly 80% by the Jos-Bukuru Complex which is widely acclaimed to lie at the focal point of the Younger Granite magmatic activity (Falconer, 1921). Along the southern escarpment of the Neil s valley are the Rhyolites and pyroclastics. 1

2 Figure 1: Plateau State Showing the Study Area. METHODOLOGY Water samples were obtained from 30 hand-dug wells, distributed within the different rock types within the study area all 30 were analyzed for physical, chemical and biological parameters. GPS positions were taken for each well point using a Garmin model 72 GPS. At each sample location the wells selected where closed and undisturbed to ensure obtaining representative samples. Water samples were collected using a 75cl plastic bottle. The bottles were rinsed with ionized water before samples were collected; a cooler with ice packs was used to store the samples in the field before taken to the laboratory. This was to avoid a rise in temperature which will cause excessive growth or death of bacteria and unwanted chemical activity which will give wrong results. These samples were conveyed to the laboratory for determination of the required data for water quality. Analytical procedures for physical, chemical and bacteriological parameters are generally in accordance with the specifications and standard methods of USEPA (1989) (United states Environmental protection Agency) standard. Turbidity and colour where tested with the spectrophotometer, ph was estimated using the HANNA ph meter, model HI 98129, TDS was measured using the TDS/conductivity meter (HACH) model Total hardness Ca 2+,Mg 2+, Cl -, using the digital titrator (HACH) model , NO 3 -, Fe,Cu, SO 4 2-, Mn were measured using the spectrophotometer. The biological parameters including faecal coliform and total coliforms where tested using the ELE international paqualab system a multipurpose water testing unit. RESULTS AND DISCUSSIONS The results of physical, chemical and bacteriological parameters analyzed for the 30 water samples are presented in Tables 1, 2 and 3 respectively. A statistical summary of these parameters is given in Table 4, the following sections presents the necessary evaluation and interpretation of the Tables. 2

3 Table 1. Results of Physical Parameters of Groundwater Table 2. Results of Chemical Parameters of Groundwater Samples from the Study Samples in the Study Area Area. Sampl es Temp o C Colour, pt.co Turbidity, NTU T.D.S ph S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S Samples Total Hardness Ca 2+ Mg 2+ Cu 2+ Fe (T) Mn 2+ NO -3 SO 4 2- Cl - S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S

4 Table 3. Result of the Bacteriological Analysis of Borehole Table 4. Statistical Summary of Groundwater Chemistry and Bacteriological Water Samples Composition Sample Faecal Coliform (cfu) Total Coliform (cfu) S S2 8 8 S3 0 0 S4 0 0 S5 6 6 S6 2 4 S7 0 0 S8 2 2 S9 4 4 S S S S S S S S S S S S S S S S S S S S S N Minimum Maximum Mean Std. Deviation ph T.D.S Total Hardness Calcium Magnesium Copper Iron E Manganese Nitrate Sulphate Chloride Feacal Coliform Total Coliform

5 The Total Dissolved Solids This was noticed to be high in the center of the study area probably due to the increase in Nitrates at the center (Fig. 2). Figure 2: Spatial Distribution of TDS in the Study Area Nitrate Nitrate had the same pattern with TDS because it was the largest contributor to the elevated values of TDS in the center and south western part of the study area (Fig.3). Figure 3: Spatial Distribution of Nitrate in the Study Area. ph The ph in the study area shows the reverse of what obtains for both the Nitrate and TDS as shown in Figure 4. The center and the southern part of the study area had very low ph, lower than the WHO guideline of ph is related in several different ways to almost every other water quality parameter as aqueous chemical equilibria invariably involves hydrogen (and hydroxyl) ions. 5

6 Figure 4: Spatial Distribution of ph Sulphate Primarily, where ph is less than 7, formation of gaseous hydrogen sulfide easily occurs, yielding bad-eggs odours in waters prone to sulphur contamination. Sulphate is seen here to increase in the areas where ph was recorded to be low although values were not above the WHO guidelines (2004)(Figure 5). Figure 5: Spatial Distribution of Sulphate Feacal Coliform Microbiological integrity of water is dependent upon the ph level, which influences the effectiveness of chlorine disinfection. Feacal coliform was lower in areas where ph was low in the middle of the study area. Figure 6: Spatial Distribution of Feacal Coliform. 6

7 The centre of the study area has low values of Faecal coliform; this could be explained by the fact that at low ph as seen in Figure 4 influences the effectiveness of chlorine disinfection occurring at the center of the study area (Figure 7) Figure 7: Spatial Distribution of Chloride Other parameters although do not show very significant variation from our statistical analysis have some interesting patterns when their variations are assessed spatially. Hardness Hardness which is not a specific constituent but a variable and complex mixture of cations and anions. It is predominantly due to calcium and magnesium although strontium, barium and other polyvalent ions like iron, manganese and zinc contribute to it. They react with certain anions such as carbonate, sulphate, nitrate, silicate and hydrogen carbonate to form a precipitate (Gray, 1994). This fact was supported by spatial variation of hardness, magnesium and calcium. Magnesium and calcium characteristics seem to have contributed to the Hardness in the eastern to central part of the study area (Figures 8, 9, 10). Also chloride, Nitrate and sulphate (which are the anions) seem to align their concentrations at the central part of the study area thus, contributing to the Hardness (Figures 8, 5, 3). Figure 8: Spatial Distribution of Hardness 7

8 Figure 9: Spatial Distribution of Magnesium Figure 10: Spatial Distribution of Calcium Iron and Manganese Iron and manganese has a similar distribution spatially in the study area. They both require somewhat reducing conditions in rocks or soils. These two are also very unlikely to cause a threat to health at concentrations occasionally recorded in water supplies (Figures 11 and 12). Figure 11: Spatial Distribution of Iron. 8

9 Figure 12: Spatial Distribution of Manganese. Factors Controlling Groundwater Quality in the Study Area. There are several processes that determine the hydro geochemical changes that happen to groundwater quality, these are leaching, mineral dissolution and precipitation. These processes work through several factors over time to bring a usually general increase in the content of dissolved solids and the major ions (Olobaniyi et al 2007). Factors like the nature of lithology which constitutes the medium of groundwater flow, quality of recharge water and resident time help to determine the prevalent hydro geochemical processes. Also these processes can be considered generally along two factors, whether they are geologic or anthropogenic. In other to evaluate which among these two factors are controlling the water quality of the study area, factor analysis has been employed. Factor analysis Factor analysis assumes that observed variables are products of linear combinations of some few underlying sources variables known as factors. It therefore attempts to find out these factors, which can explain a large amount of the variance of the analytical data. The obvious advantage of factor analysis over the customary piper and stiffs schemes stems from its ability to reveal hidden inter-variable relationships and allows the use of virtually limitless numbers of variable, thus trace elements and physical parameters can be part of the classification parameters. By its use of raw data as variable inputs, errors arising from close number systems are avoided. Also because elements are treated as independent variables, the masking effect of chemically similar elements that are often grouped together is avoided (Dalton and Upchurch, 1978). This method has been shown to be effective in several studies. These include hydrochemical characterization of the Mogi-Pardo watershed (Invernizzi and Barros de Oliveira, 2004) and characterization of the chemical facies of groundwater in the deltaic plain sands aquifer of Warri, western Niger Delta, Nigeria (Olobaniyi and Owoyemi, 2006). The result of the factor analysis indicates three factors. The first factor accounts for % of the variance, the second % and the third %. All the remaining factors are not significant. The three factors account for 81.39% of the total variance in the dataset. (Table 5). Factor 1, which explains % of the total variance, includes Mg, Ca, total hardness and ph. This factor reflects the signatures of natural water recharge and watersoil/rock interaction. Surface water charged with atmospheric and biogenic CO 2 infiltrates into the subsurface and aggressively attack aluminosilicates including feldspars and micas present in the formation liberating cations such as Ca and Mg into the water and leaving residues of clay minerals. A consequence of this incongruent dissolution is a rise in ph and in HCO 3 concentration of the water (Freeze and Cherry, 1979). This in essence reflects the geology or rock type of the area. 9

10 Table 5: Results of Rotated Component Matrix of the Parameters Rotated Component Matrix(a) Component Variables Factor 1 Factor 2 Factor 3 Total coliform Feacal coliform Chlorine.787 Sulphate.807 Nitrate Manganese.817 Iron.800 Magnesium.954 Calcium.952 Total Hardness.954 T.D.S.839 ph % of Variance Cumulative % Factor 2, this explains % of the total variance, it includes Nitrates, chlorine, total coliform and feacal coliform loading on it substantially. These represent the anthropogenic factor or human activity. They could result from sewages, fertilizers, leachates, refuse and pesticides. These contaminants are not associated with the geology of the area but human activities. Although factor 1 (geology) seems to be the controlling factor in the study area it is followed in a near second by these anthropogenic contaminants where in certain places of the study area had concentration of nitrates above the WHO stipulated standards (2004). Factor 3, explains for % of the total variance and has sulphate, Manganese, iron loaded on this factor substantially. Iron and manganese are transitional elements that depict an anaerobic or reducing environment. They account for the smallest percentage in the total variance. CONCLUSION The results above indicates groundwater of high Nitrates, the TDS and nitrate shows the same spatial distribution occurring at the center of the study area particularly around Jos Township or the Jos Biotite Granite rock type. Thus we conclude that these high nitrate values are more directly responsible for the rise in TDS of the study area, while the low levels of ph recorded in the center of the study area are responsible for the elevated levels of chloride and sulphate also for the high level of feacal integrity at the middle of the study area. The representation of hardness at the western part of the study area is replicated by the spatial distribution of calcium and magnesium. Implying they both contributed to level of hardness in the study area. The conditions responsible for concentration of iron and Magnesium are the same as spatial distribution is similar. The analysis of the factors controlling the quality of groundwater in the study area showed that the groundwater in the study area is mostly controlled by the geology or natural water recharge and soil/rock interaction this accounts for 37% of the total variance with parameters like Mg, Ca, total hardness and ph as indicators of this fact. The anthropogenic factor indicated by nitrate, feacal coliform, total coliform and chlorine accounts for % of the total variance, seems to suggest that human activities is making a deep impact on the groundwater quality. The transition element (iron and manganese) and sulphate account for the rest of the total variance of % having to least influence on the groundwater. 10

11 High level of feacal coliforms causes gastroenteritis in humans and animals, being especially serious in newborn infants and children under five years of age. This disease does not causes fever but profuse watery diarrhea with little mucous, nausea and dehydration. Manganese has occasionally high values that can cause staining in laundry within the study area. In terms of hardness the quality of the water range from soft to moderately hard; this is good as consumers would not spend on soap. REFERENCES Eziashi, A.C., (1995). Analysis and Classification of Natural River Channels on the Jos Plateau. Unpublished PhD Thesis. Department of Geography and Planning. University of Jos. Falconer, J.D. (1921). The Geology of the Plateau Tinfields. Bull. Geol.Surv. Nigeria. No.1. Gray N. F. (1994). Drinking Water Quality Problems and Solutions. John Wiley and Sons, England. Pp Olobaniyi, S.B, Ogala, J.E. and Nfor, N.B. (2007).Hydrochemical and Bacteriological Investigation of Groundwater in Agbor Area, Southern Nigeria. Journal of Mining and Geology Vol 34.Pp Olobaniyi, S. B. and Owoyemi, F. B. (2006). Characterization by Factor Analysis of the Chemical Facies of Groundwater in the Deltaic Plain Sands Aquifer of Warri, Western Niger Delta, Nigeria. African Journal of Science and Engineering Series. Vol. 7, No. 1. Pp Dalton, M.G and Upchurch, (1978). Interpretation of Hydrochemical Facies by Factor Analysis, Groundwater. Vol. 16 No. 4. Pp Invernizzi A. L. and Barros de Oliveira S. M. (2004).Hydrochemical Characterization of a Watershed through Factor Analysis. Aguas Subterraneas, Calvados. No. 18/Janeiro. c3sl. ufpr.br Freeze, R.A. and Cherry, J.A., (1979). Groundwater. Prentice-Hall, Inc. New Jersey. Pp USEPA (1989). Guidance Document on the Statistical Analysis of Ground Water Monitoring Data at RCRA Facilities. Interim Final Guidance, Office of Solid Waste Management Division. Washington, D.C. World Health Organization (2004). Guidelines for Drinking-water Quality, Vol. 1: Third edition Recommendations. World Health Organization, Geneva. Received for Publication: 02/04/2010 Accepted for Publication: 04/05/2010 Corresponding Author: Aga, T. Department of Geology and Mining, University of Jos, Nigeria tergaus@yahoo.com 11