Journal of Spatial Hydrology

Volume 11 Number 1 Article 5

2011

Studies on Major Ion Chemistry and Hydrogeochemical Processes of Groundwater in City, Southern

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Studies on Major Ion Chemistry and Hydrogeochemical Processes of Groundwater in Port Harcourt City, Southern Nigeria

H. O Nwankwoala and G.J Udom

Abstract Of recent, the rapid deterioration of groundwater quality in Port Harcourt, Southern Nigeria due to unregulated exploitation resulting from increasing growth in the oil and gas production activities has become a major concern. The predisposition of groundwater to pollution and the realization of its serious health and economic consequences demand knowledge of the ambient groundwater quality and of the processes leading to an improved understanding of the groundwater in the area. Groundwater samples were collected from eighteen (18) representative boreholes spread over the Port Harcourt City. This was done to assess and determine the geochemical processes occurring within the aquifer systems using groundwater chemistry and ionic ratios. Properties such as electrical conductivity, pH and major ion concentrations, such as

Ca, Mg, Na, K, Cl, HCO3, and SO4, of groundwater were taken into consideration. Concentrations of these cations and ions in the groundwater systems of the area vary spatially and temporally.

Abundance of these ions are in the following order: Ca > Mg >Na > K = HCO3 > Cl > SO4 > NO3.

Ca - Mg - HCO3 and Ca- Mg- SO4- Cl are the dominant hydrochemical facies of the study area. Results show that ion-exchange processes, carbonate and silicate weathering are responsible mechanisms for the groundwater chemistry of the area. Hydrochemical indices (Mg/Ca, Cl/HCO3 and Cation Exchange Values (CEV) generally indicates low- salt inland waters, with minimal marine influence. The hydrochemical evidence reveals the importance of recent management decisions (reduced exploitation/controlled pumping) in determining the evolution and distribution of groundwater salinity within the aquiferous zones. This framework, as the study observes, will lead to improved understanding of the hydrochemical characteristics of the aquifer systems of the area.

Introduction Following huge oil exploration and production activities in Port Harcourt area, there is a continuous increase in demand for fresh groundwater, the major source of urban water supply for domestic and industrial uses. The increased rate of groundwater abstraction rate poses severe pressure on groundwater resources, as almost every home has a well. Also, most of the companies that generate chemical effluents discharge their wastes directly into the sea or creeks, without regard to the effects of the effluents on coastal aquifers and aquatic life.

Groundwater chemistry is largely a function of the mineral composition of the aquifer through which it flows. The hydrochemical processes and hydrogeochemistry of the groundwater vary spatially and temporally, depending on the geology and chemical characteristics of the aquifer. Apodaca, et al., (2002), Martinez & Bocanegra, (2002), have inferred that hydrogeochemical processes such as dissolution, precipitation, ion-exchange processes and the residence time along the flow path control the chemical composition of groundwater.

Abimbola, et al., (2002); Olatunji, et al., (2001), also established that geology plays a significant role in the chemistry of subsurface water. Moreso, the importance of mineral diagenesis in the geochemical evolution of groundwater has been elucidated by (Wicks, et al., 1995; Back, et al., 1983; Plummer, 1977; Bredehoeft et al., 1983; Hendry & Schwartz, 1990). Studies by

______Department of Geology, University of Port Harcourt, P.M.B 5323, Choba, Port Harcourt, Nigeria.

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(Goldenberg et al., 1986; Jones et al., 1969; Drever, 1988; and Keller et al., 1991) have shown that when soluble minerals undergo diagenetic reactions, they provide a medium for cation- exchange reactions as well as present a significant influence on the geochemistry of an aquifer system.

Previous studies carried out in the area have tended to emphasize only the general water supply problems (Etu- Efeotor & Odigi, 1983; Amajor, 1986). Amadi, et al., (1989) assessed the hydrogeochemistry of groundwaters in parts of the Niger Delta. Etu-Efeotor, (1981); Udom, et al., (1999); Nwankwoala, et al., (2007), acknowledged that the groundwater quality in the area is rapidly deteriorating. Increase in population and rapid urbanization has made groundwater the major source of water supply, hence, it is very essential to understand the hydrogeochemical processes that take place in the aquifer system. In this paper, an attempt is made to evaluate the different water types and hydrogeochemistry of the main source of water supply in the area. This study also provides an opportunity to observe a detailed profile of the hydrogeochemical facies distribution and processes of groundwater, with a view to predicting their water character.

The Study Area

Port Harcourt City is located within the Niger Delta Basin of Southern Nigeria. The area lies between latitudes 4030’ and 5000’N and longitudes 6045’ and 7030’E (Fig.1). The area is characterized by alternate wet and dry seasons (Iloeje, 1972). The rainy season starts in March and ends in October, with a peak in June and July. The rains are ushered in by the south west rain bearing winds which blow from the Atlantic Ocean into Nigeria. Within the rainy season, there is a short period of little or no rain called the ‘August Break’ which is commonly experienced in the month of August. The dry season begins in November and lasts till March, with a short harmattan in December and early January. It is brought by the dry northeasthern winds which blow across the Sahara desert into Nigeria. Relative humidity values are generally over 80%, and the mean annual temperature is about 280C in the area. Fishing, small scale agriculture and huge oil exploration and exploitation dominate economic activities in the area.

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Fig. 1: Location Map of Study Area Showing Sampled Points

Brief Geology/Hydrogeology of the Area Port Harcourt, one of the coastal cities in the southern part of Nigeria is located within the oil rich Niger Delta Sedimentary Basin. Figures 2 and 3 show the spatial variability of boreholes and water depth in the study area. Generally, the Delta is characterized by three formations, namely Akata (oldest), Agbada and Benin (youngest). These formations consist primarily of regressive Tertiary age sediments. The detailed geology of the Niger Delta formation is given by Reyment (1965), and Short & Stauble, (1967).

The basal Akata Formation consists of low density, high pressure, shallow marine to deep water shales (Schield, 1978). The Agbada Formation consists of alternating deltaic (fluvial, coastal, fluviomarine) sands and shale. The Benin Formation (Miocene – Recent) consists of freshwater continental (fluviatile) sands and gravels, with occasional clay layers, and an overall thickness of 2100m thick at the basin centre (Weber & Daukaro, 1975). It is the most prolific aquifer in the study area. Overlying this formation are the Quaternary deposits, 40 – 50m thick (Table 1): an unconfined aquifer sequence comprising rapidly alternating sequences of sand and silt/clay, with the latter becoming increasingly prominent seawards (Etu-Efeotor & Akpokodje, 1990; Ngah, 2002).

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The thin clay units in the Benin Formation have resulted to a multi-aquifer system in the study area as it is the case in most parts of the Niger Delta where this formation outcrops (Etu-Efeotor, 1981; Edet, 1993; Udom et al., 1997, 1998). Etu-Efeotor (1981) identified two major aquifers in from strata logs. The upper one is more prolific and extends to about 80 metres, while the underlying one is less prolific. Studies by Etu-Efeotor & Odigi, (1983), Amadi, (1986), Odigi, (1989), Amadi & Amadi, (1990), Nwankwoala et al., (2008), and other available borehole records from the Rivers State Water Board as well as information from other water agencies, show that borehole depths in the state commonly range from 35 – 90 metres; Static Water Level (SWL), 1 -20metres; transmissivity, 500 – 10,000m2/d; and hydraulic conductivity, 5 – 60m/d.

Table 1: Quaternary deposits of the Niger Delta (after Etu-Efeotor & Akpokodje, 1990)

Geologic Unit Lithology Age

Alluvium Gravels, sand, clay, silt

Freshwater, back swamps Sand, clay, silt, gravel

Mangrove and some saltwater/ Medium-fine sands, clay and some silt Quaternary Back swamps

Active/abandoned beach ridges Sand, clay and some silt

Sombreiro-Warri deltaic plain Sand, clay and some silt

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Fig. 2: Contour Map for the depth of boreholes in the study area.

Fig. 3: Digital Elevation Model of water depth in the study area Journal of Spatial Hydrology 38 Nwankwoala and Udom JOSH vol. 11 (34-40)

Materials and Methods

Groundwater samples were collected from eighteen (18) representative boreholes spread over the greater Port Harcourt City during December 2009 to January 2010. It is generally believed that water samples taken from a pumping well may not represent the true chemical character of water in the aquifer hence samples were collected from the well head, that is, the tapping on the pumping main and at points close to the well head as much as possible. Samples were collected in polyethylene bottles. Before sample collection, the bottles were properly rinsed with the borehole water to be sampled, filled to the brim, tightly covered to retain the CO2 that was in the water when the sample was taken and to avoid contamination, appropriately labeled at the point of collection and transported to the laboratory in ice box for further physico-chemical analyses.

Sampling was done in good weather condition to avoid rainwater contamination, as this would affect the quality of the samples collected. A maximum of three (3) samples were collected per location to avoid possible deterioration, thus affecting the actual groundwater chemistry. Analyses of groundwater samples were carried out using standard methods as suggested by the American Public Health Association (1989).Cations were analysed using an Atomic Absorption Spectrophotometer (Perkin – Elemer AAS 3110) and the anions using the Colorimetric method with the UV- Visible Spectrophotometer WPAS 110. Standard solutions and blanks were commonly run to check for possible errors in the analytical procedures. Generally, the processes controlling the chemistry of the groundwater were identified by the systematic study of hydrochemical data.

Results and Discussion

Table 2 shows the chemical composition of the groundwater in the area. Analyses are with respect to the total ionic constituents which include the major cation and anion constituents. Results of the Physico-chemical analysis of the groundwater show that groundwater in the area is not highly mineralized, hence can generally be classified as soft, freshwater based on its hardness and TDS. Analytical results show that the groundwaters are low in pH (4.00 to 6.80) indicating slightly acidic groundwater in the area. The acidity arises from gas flaring in most parts of the Niger Delta as well as the presence of organic matter in the soil. The water should be treated to increase the level of pH at locations where values are below 6.5. This can be achieved through base-exchange method with dolomite. PVC materials should be used for borehole construction in the area since acidic waters are aggressive to iron pipes. Iron values are also high in some areas, particularly the Borokiri areas (Fig. 5). This can be treated by encouraging the iron to precipitate when the water is exposed to air. The ferric hydroxide precipitate is then filtered out to have potable water.

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Table 2: Chemical Composition of Groundwater Samples of Study Area

2 - S/ Location Tem PH EC TDS TS Hardn CI SO Fe No3 T. Eh Ca Mg Na k HC PO4 Mn Dep 2 - 2- - 3- N p S ess 4 Salinit Colifor O3 th y m

0c - µs/cm Mg/l mg mg/l mg/l mg/l mg/l Mg/l mg/ Cfu/mu mV mg/l Mg/l mg/ mg/ mg/ mg/l mg/l Metr l l l l e (m)

1 Abuloma 27. 6.10 20.00 125.0 - 3.00 78.34 4.2 0.62 - 0.01 - - 4.06 2.05 0.54 56.0 0.01 - - 3 0 5 0 0 0 2.980 0 0 30 0

2 Amadi 27. 5.80 25.00 120.0 - 4.00 13.87 7.6 0.29 - 0.00 - - 7.13 1.40 0.42 58.0 0.02 - - Flat 6 0 0 0 0 0 2.090 0 0 50 3

3 Amadi- 26. 5.20 60.00 30.00 - 10.00 15.00 0.0 0.00 - 0.02 - 124. 5.00 0.46 0.31 10.0 0.00 0.31 183. Ama 9 1 1 0 00 0 0.571 1 1 0 0 1 00

4 Borokiri 28. 6.50 72.00 34.00 - 16.00 35.50 8.2 0.12 - 0.00 - - 18.12 1.76 0.65 15.2 0.02 - 72.2 8 5 0 1 0 2.570 0 0 00 1 0

5 D/Line 29. 6.20 22.00 38.00 - 10.00 14.00 3.7 0.08 - 0.00 - - 8.57 1.85 0.65 40.2 0.01 - 36.5 0 8 0 0 0 2.950 0 0 50 0 8

6 Diobu 27. 4.80 50.00 25.00 - 4.00 20.00 21.0 0.00 - 0- - 131. 4.92 0.82 0.14 8.08 0.00 0.00 165. 0 0 1 .010 00 0 0.348 7 4 0 0 4 00

7 Diobu 26. 5.10 50.00 25.00 - 4.00 13.00 18.0 0.00 - 0.01 - 124. 3.94 0.31 0.00 7.47 0.00 0.00 255. 3 0 1 0 00 0 0.445 0 4 0 0 1 00

8 Elekahia 27. 5.20 50.00 25.00 - 15.00 10.00 0.0 0.02 - 0.07 - 130. 5.49 0.79 0.08 9.60 0.00 0.08 - 5 1 9 0 00 6 0.366 9 3 0 0 3

9 G.R.A 25. 5.90 58.00 99.00 - 8.00 29.50 0.0 0.00 - 0.- - - 7.10 1.50 0.80 21.8 0.00 - - Phase I 8 8 1 010 0 0.180 0 0 00 0

10 GRA 25. 6.80 10.00 19.00 - 8.00 7.10 0.0 0.00 - 0.01 - - 4.40 3.30 0.50 30.0 0.15 - 45.7 Phase II 5 6 1 0- 0 1.000 0 0 00 0 2

11 Moscow 27. 4.10 20.00 10.00 - 0.00 8.00 9.0 0.01 - 0.3 - 135. 4.17 0.89 0.03 10.8 0.00 0.03 77.0

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Rd 2 2 0 2 0 00 1 0.235 9 1 20 0 1 0

12 Moscow 27. 3.80 90.00 45.00 - 6.00 16.00 10.0 0.00 - 0.19 - 195. 6.54 1.03 0.40 10.3 0.83 0.40 54.9 Rd1 0 0 1 0 00 1 0.824 1 1 40 0 1 0

13 NDBDA 27. 4.14 86.00 10.00 1.0 16.00 38.00 49.9 0.20 0.00 ND 0.00 131. 5.49 0.833 1.88 0.33 9.50 0.70 0.23 - 0 0 2 0 00 3 3 3 00 0 1

14 NDDC 26. 3.77 50.00 40.00 1.0 14.00 17.00 50.0 0.02 0.00 ND 0.00 156. 0.33 1.33 0.72 10.2 0.56 0.44 - 5 0 0 1 30 7 0.777 4 3 22 7 3

15 Rumuigb 28. 4.50 70.00 45.00 1.0 15.00 16.00 10.0 0.01 0.00 53.5 2.00 134. 0.35 0.867 1.77 0.56 15.0 0.63 0.56 - o 3 0 0 2 0 30 5 7 7 00 4 7

16 Rumuok 27. 6.40 82.50 38.90 1.0 24.00 18.00 13.4 0.34 0.00 40.0 1.00 187. 0.44 0.634 1.45 0.34 17.0 0.55 0.43 - wuta 3 0 4 0 0 00 4 6 5 00 5 5

17 Rumuola 28. 5.00 70.00 40.00 1.0 23.00 15.00 11.2 0.22 0.00 30.0 1.00 150. 0.35 0.550 1.35 0.22 15.0 0.43 0.22 - 2 5 3 2 0 22 6 6 2 12 4 3

18 Rumuom 27. 4.00 75.00 35.00 1.0 22.00 14.00 10.0 0.32 0.00 40.0 1.00 160. 0.30 0.400 1.23 0.12 14.0 0.22 0.55 - asi 2 0 0 5 1 00 0 4 3 00 2 5

WHO (2004) NS 6.5- 500 500 NS 500 250 250 0.3 NS 50 NS NS 7.5 50 200 200 NS 10 0.1 8.5

NS = Not Stated

Table 3: Major ion concentration (meq/L) with % present in the groundwater samples and the corresponding water types.

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- + 2+ 2 S/NO Location Na+K Ca Mg HCO3- CI+NO3- SO4

meq/L % meq/L % meq/L % meq/L % meq/L % meq/L % Water Type

1 Abuloma 0.0813 13 0.3565 58 0.1742 29 0.9516 63 0.3907 26 0.1583 11 Ca(HCO3)2

2 Amadi Flat 0.0220 15 0.2300 35 0.0312 19 0.1339 20 0.1272 30 0.1343 35 CaCl2

1 3 Amadi-Ama 0.1071 19 o.2030 36 0.2483 45 0.9185 28 2.2075 70 0.0885 2 MgCI2?

4 Borokiri 0.1008 13 0.4285 55 0.2458 32 0.6598 58 0.3944 35 0.0788 7 Ca(HCO3)2

5 D/Line 0.0204 10 0.3340 30 0.4318 42 0.1565 20 0.0383 45 0.0012 40 CaCl2

6 Diobu 0.0967 8 0.9060 74 0.2142 18 0.2492 16 1.0846 78 0.1719 8 Ca(HCO3)2

7 Diobu 0.0317 12 0.1833 40 0.1235 15 0.2316 30 0.8142 40 0.1344 9 CaCl2

8 Elekahia 0.0288 8 0.2500 77 0.0475 15 0.1639 28 0.4239 72 0.0002 0 CaCI2

9 G.R.A Phase I 0.0344 20 0.1617 50 0.0221 20 0.1356 15 0.1050 45 0.1314 40 Ca(HCO3)2

10 GRA Phase II 0.0443 25 0.9592 40 0.5560 50 0.2215 25 0.3340 30 0.0113 17 CaCI2?

4 11 Moscow Rd 2 0.0142 8 0.1970 78 0.0371 14 0.1225 14 0.3669 43 0.3750 43 CaCI2?

3 12 Moscow Rd1 0.0447 23 0.1261 63 0.0290 14 0.1324 12 0.5640 50 0.4375 38 CaCI2?

13 NDBDA 0.0516 30 0.2371 30 0.3356 45 0.1130 30 0.1123 35 0.1163 20 CaCl2

14 NDDC 0.0420 12 0.2498 78 0.0305 10 0.1573 35 0.2274 65 0.0002 0 CaCI2

15 Rumuigbo 0.0886 20 0.3550 77 0.0150 3 0.3573 30 0.8316 70 0.0015 0 CaCI2

2 16 Rumuokwuta 0.1628 35 0.2200 47 0.0833 18 0.4918 60 0.2007 24 0.1263 15 Ca(HCO3)2?

5 17 Rumuola 0.0415 16 0.2085 77 0.0195 7 0.1773 30 0.2274 38 0.1875 32 CaCI2?

18 Rumuomasi 0.0617 14 0.2970 70 0.0686 16 0.1695 20 0.4642 55 0.2083 25 CaCI2

?=No dominant cation and anion, probably those suggested

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Major Ion Chemistry and Chemical Processes

Major ions constitute a significant part of the total dissolved solids present in groundwater. The concentration of the ions in groundwater depends on the hydrogeochemical processes that take place in the aquifer system (Lakshmanan, et al., 2003). These processes occur when the groundwater moves towards equilibrium in major ion concentrations hence the study of concentrations of various major ions present in groundwater is used in the identification of geochemical processes.

The major ions in the groundwater systems in the area present a definite spatial trend (Figures 4 & 5). Areas around Abuloma show relatively high Chloride. Tables 3 shows that the ratio of the + + + 2+ - - - - cations (Na , K , Ca and Mg ) and anions (HCO3 , NO3 , SO4 , and Cl ). The abundance of these ions are in the following order: Ca > Mg > Na > K = HCO3 > Cl > SO4 > NO3. Calcium is the dominant cation while Bicarbonate dominates the anionic components of the groundwater.

The mechanisms controlling water chemistry may be caused by several factors during the interaction. Hence, ionic ratios and plots were used to discriminate between them. The contribution of atmospheric sources to the dissolved salts has been discussed by many authors (e.g. Garrels & Mackenzie, 1971; Stallard & Edmund, 1983; Sarin et al., 1989; Berner & Berner, 1996). Chloride is the most useful parameter for evaluating atmospheric input to water as it shows very little fractionation (Appelo & Postma, 1993).

Sodium (Na) values range from 0.31mg/l to 3.300mg/l while Chloride (Cl) range from 7.10mg/l to 78.34mg/l, which are below the WHO (2004) Standards (Table 2). Sodium and chloride inputs are likely to be mainly from rainfall and, therefore, will largely reflect the ratio observed in seawater. Cation exchange may account for a reduction in the Na concentration, and halite dissolution may account for relatively high concentration of Cl.

Hydrochemical Indices and Facies

The ionic relationships Mg/Ca, Cl/HCO3, and the Cationic Exchange Value (CEV) = {Cl – (Na + K)}/ Cl) (Table 4) were part of the study to check the salinity and origin of the groundwater in the study area. Mg/Ca values measured were all less than 1.0 (Table 4) ranging from 0.03 to 0.77. The water in the area appears to be of inland origin because waters under marine influence would have values of about 5 (Sarma & Krishnaiah 1976) except where other processes such as cationic exchange intervene, when the values could be 4 or less.

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Table 4: Hydrogeochemical indices Mg/Ca, CI/HCO3, and Cationic Exchange Value in water samples. S/N Mg/Ca CI/HCO3 CEV

1 0.29 0.24 0.87

2 0.73 1.39 0.97

3 0.34 0.35 0.82

4 0.14 2.53 0.94

5 0.22 0.24 0.47

6 0.03 1.35 0.92

7 0.07 2.48 0.95

8 0.11 0.74 0.98

9 0.11 0.50 0.95

10 0.07 0.04 0.91

11 0.06 0.74 0.88

12 0.13 1.55 0.91

13 0.23 0.24 0.95

14 0.03 0.17 0.96

15 0.12 0.77 0.85

16 0.77 0.73 0.92

17 0.13 2.56 0.86

18 0.24 2.33 0.91

Cl/HCO3 values (Table 4) ranged from 0.04 to 2.56. Values of this hydrogeochemical index given for inland waters are between 0.1 and 5, and for seawater between 20 and 50 (Custodio, 1987). In general, the CEV for seawater ranges from +1.2 to +1.3 (Custodio, 1983), whereas low salt inland waters give values of close to zero, either positive or negative. The CEV values for groundwater in the area are generally below 1.0 (Table 4) ranging from 0.47 – 0.98 indicating that the groundwater is inland with respect to provenance.

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Cl 3 Cl/HCO

Mg/Ca Na

Ca

Na

Fig.4: Scatter plots Showing Relationship between some of the anions and cations.

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The diagnostic chemical character of water solutions in hydrologic systems has been determined with the application of the concept of hydrochemical facies (Back, 1966), which enables a convenient sub-division of water compositions by identifiable categories and reflects the effects of chemical processes occurring between the minerals within the subsurface rock units and the groundwater. In order to gain better insight into the hydrochemical processes operating in the groundwater systems of the area, the Piper diagram was used for the major cations and anions. This method proposed by Piper (1944) is applied to show the relative concentration of the major 2+ 2+ - - - 2- cations (Ca , Mg , Na + and k+) and anions (HCO3 , Cl , NO3 and SO4 ).

From the Piper Trilinear plot (Piper, 1944) of the major ions concentration of water samples, two principal hydrochemical water types were delineated i.e Calcium Magnesium Bicarbonate (Ca – Mg – HCO3) type water which are dominated by alkaline earth and weak acids (Karanth, 1994). Calcium Magnesium Sulphate Chloride (Ca – Mg – SO4 – Cl) is the second type identified. Secondary alkalinity (Carbonate hardness) and secondary salinity (Non Carbonate hardness) in both water types were identified. Bicarbonate and Chlorides of Calcium dominate the groundwater (Figure 6). Calcium Chloride is the most prevalent cation facies, while the anion facies are Bicarbonate and Chloride (majority) type. Only a few fall in the “no – dominant” class in the anion facies. Following this observation, and on the basis of the dominant cations and anions, the groundwater in the area can be classified as Calcium Chloride (CaCl2) and Calcium Bicarbonate (Ca (HCO3)2 types. This assertion is based on the analytical results. The facies is indicative of the geochemical processes occurring between the minerals in the rocks and the groundwater system.

(a) (b)

Fig. 5 : Spatial Analysis of Anions and Cations in the Sampled Locations

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Ca‐Mg‐SO4‐Cl

...... Ca‐Mg‐HCO3

Mg SO4

...... Ca ...... Na+k HCO3 Cl %meq/l

Fig. 6: Piper Trilinear Diagram Showing the Chemical Characters of the Groundwater in the Study Areas

Conclusion

In this study, serious attempts have been made to investigate the hydrochemical characteristics of the aquifer, in addition to explaining the origin as well as the mechanisms taking place in the groundwater systems of the area. The study has made it possible for a better understanding of the dominant geochemical mechanisms that account for compositional variations of the chemical profile. Generally, the groundwater of the study area is dominated by the major ionic components,

Ca, Mg, Na, HCO3, Cl and SO4, which is in agreement with the Piper plots revealing (Ca – Mg –

HCO3 and Ca – Mg – SO4 – Cl) water types, which indicate a close proximity to the coastal areas.

Result also reveals that the groundwater is characterized by secondary alkalinity and salinity, as well as its carbonate and non-carbonate hardness. The hydrochemical indices reveal that the groundwater is of inland origin, with Cation Exchange Value (CEV) generally below 1.0, indicating low-salt inland water.

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Following the results of this study, it is recommended that further studies leading to improved understanding of the hydrogeochemical characteristics of the aquifer systems in the area be carried out.

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