Integrated Geochemical Indicators and Geostatistics to ... · Fig. 3: Map showing the location of...

Middle East Journal of Applied Sciences ISSN 2077-4613

Volume : 08 | Issue :03 |July-Sept.| 2018 Pages: 939-956

Corresponding Author: Ehab Zaghlool, Hydrogeochemistry Dept., Division of Water Resources and Arid Land, Desert Research Center, 1 Mathaf Al Mataria St., Mataria, P.O.B. 11753, Cairo, Egypt. E. mail: [email protected]

939

Integrated Geochemical Indicators and Geostatistics to Asses Processes Governing Groundwater Quality in Principal Aquifers, South Sinai, Egypt

Ehab Zaghlool and Mustafa Eissa

Hydrogeochemistry Dept., Division of Water Resources and Arid Land, Desert Research Center, 1 Mathaf Al Mataria St., Mataria, P.O.B. 11753, Cairo, Egypt

Received: 26 June 2018 / Accepted: 29 August 2018 / Publication date: 15 Sept. 2018 ABSTRACT

The groundwater system in the principal aquifers situated in the Southern Sinai was regionally investigated, using hydrochemical tools and geostatistical technique to evaluate the recharge sources and salinization origins which consider the main constraint for sustainable development in such an arid region. The environmental stable isotopes (δ18O and δ2H), groundwater salinity, conservative ions (Cl and Br), ion ratios and the sea water mixing index (SWMI) were utilized to identify the salinization mechanism and to delineate the recharge for different aquifers (Quaternary, Miocene, U. Cretaceous, L. Cretaceous and Precambrian) situated in the upstream watersheds and along the coastal regions. The regional study depends on four hundred and sixty-eight groundwater samples tapping the main aquifers. The geochemical data have been analyzed statistically to estimate the seawater mixing index (SWMI) in order to delineate the deteriorated aquifer zones. The environmental stable isotopes confirm the upstream of Gharandal, Watir, Dahab basins and Saint Catharine areas receives considerable amount of the annual precipitation that could be managed for sustainable development. The hydrochemical ion ratios and the SWMI values give good insights for aquifer salinization, where; mixing with seawater intrusion in the downstream coastal aquifers, leaching processes of minerals in the aquifer matrix, evaporation processes are considered the main sources for aquifer deterioration. The hydrogeochemistry shows the injection of high saline water comes from the desalination plant deteriorates the coastal Miocene aquifer located in Sharm El Shiekh and Nabaq areas. Keywords: Groundwater chemistry, Statistics, rCl/rBr, Sable isotopes, South Sinai Peninsula

Introduction

The South Sinai Peninsula is located in the coastal arid region, where the groundwater recharge is limited and seawater intrusion threatens the groundwater quality due to the over withdrawal. The groundwater is the main source of drinking and potable uses for about 177,900 inhabitants (South Sinai, 2012). Groundwater salinization is an environmental global phenomenon that affects many different aspects of our life (Williams, 2001). The groundwater quality deterioration is considered one of the most important challenges facing the sustainable development strategies in arid and semiarid areas. In the coastal arid aquifers, groundwater salinization processes mainly arisen from seawater mixing, geogenic sources, evaporation, and dissolution as well as the anthropogenic activity such as over-exploitation and rejecting brine deeper into aquifer saturated zone (S´anchez-Martos et al., 2002; Indu et al., 2013).

Recently, the environmental stable isotope in conjunction with conservative ions rCl/rBr as well as other geostatistical and geochemical tools have been used to explain the factors deteriorate the groundwater quality (Alcala and Custodio, 2008; DeMontety et al., 2008; Carol et al., 2009; Ben Hamouda et al., 2010; Han et al., 2011). The Cl/Br ratio gives good insights related to the groundwater contamination and mixing due to its constant value from different end members. The value of rCl/rBr can not significantly modified by the anthropogenic or the physical processes taking place in soil including dilution, evaporation, transpiration (Samantara et al., 2015). Stable isotopes (δ18O and δ2H) are used to identify recharge source of groundwater (Clark and Fritz, 1997; Mook, 2001) and the mixing with seawater in coastal aquifers (Leduc et al., 2007). The previous studies (Mazor et al.,1973; Gat and Issar, 1974; Tantawi et al. 1998; Abd El Samie and Sadek, 2001;

Middle East J. Appl. Sci., 8(3): 939-956, 2018 ISSN 2077-4613

940

Saied, 2004; Zaghlool, 2006; Rosenthal et al., 2007; El-Sayed et al., 2011; Eissa et al., 2016; Isawi et al., 2016) have been conducted on the Southern Sinai aquifers using hydrochemical ratios and environmental stable isotopes as a tracer to identify the origin of salinity. However, no regional research has been conducted on the global aquifers located in the South Sinai governorate, in order to delineate the promising localities and aquifer zones that receives significant and sustainable recharge from annual precipitation. In this research the geochemical indicators, statistical analyses and isotopic tracers have been utilized to identify the main recharge sources for different aquifers and sources that cause groundwater deterioration for sustainable developmental strategies.

Study Area

The study area located in the southern part of Sinai Peninsula located in between longitude 32º 00˴ to 35º 00˴ (East) and latitude 28º 00˴ to 30º 30˴ (North). It covers an area about 31,272 Km2 and bounded from the north by the North Sinai governorate, from the South by The Red Sea, from the East by the Gulf of Aqaba and from the East by the Gulf of Suez (Figure. 1). South Sinai generally characterized by the an arid climate, where the annual mean temperatures range from 18 °C to 33 °C, with less than 50 mm of annual precipitation and the wind blows from the northwest in summer and from the southwest in winter (Caragnano et al., 2009; Hereher, 2015).

Fig. 1: Location map of the Southern Sinai, Egypt

The South Sinai region comprises four main principle aquifers; the Precambrian (basement rocks), the Miocene, Cretaceous, and the Quaternary aquifer. The Precambrian aquifer, exposed in


941

the upstream watershed areas and is mainly composed of granites, and gabbros. The groundwater occurs in the fractured media and in the weathered surface zone up to 5m depth. The Precambrian aquifer in South Sinai receives an annual recharge estimated 52,000 m3/day (Dames and Moore, 1985).

Fig. 2: The main surface geologic setting of Southern Sinai, Egypt (Omara, 1972; Kora, 1995; Abdel

Zaher et al., 2014).

The Cretaceous aquifer are represented by the middle and the lower Cretaceous units. The lower Cretaceous unit (Nubian sandstone) consists of sandstone together overlayed with the Cenomanian sandstone that has been considered the upper unit of the Nubian sandstone (Dames and Moore, 1985; Sultan et al., 2011). The tertiary units serving as aquifers, belonging to the lower Miocene age and formed mainly of sandstone and grits, at the basal Miocene unit (Shata, 1992). The aquifer thickness together with the upper confining unit varies between 100 m near its outcrops along the eastern catchments and gradually increases westward to reach about 450 m thick along the Gulf of Suez. The aquifer discharges westward into the Gulf of Suez with minor discharge represented by natural springs along shoreline at Hammam Faroun and Hammam Mousa springs (El-Rayes et al., 2014). Quaternary aquifers, is mainly composed of sands, gravels, and silt mixed with rock fragments in wadi alluvial along many of the major wadis and at the downstream deltas. The aquifer thickness varies between 3 and 150 m and the depth to water level ranges between 2 m and 47 m (El-Rayes et al., 2014).

Methodology

The water-chemistry data analyzed in this paper include water samples collected from the previous publications in South Sinai during the last decades. These data included 468 groundwater samples from 5 principal aquifers, 3 seawater samples and 2 rain sample (Table, 1), (Figure. 3). The


942

chemistry data of all water samples are available, (Isawi et al., 2016; Eissa et al., 2016; Abouelmagd et al., 2014; Omran, 2013; El-Sayed et al., 2011; El-Fiky, 2010; El-Fiky, 2009; Rosenthal et al., 2007; Zaghlool, 2006; Saied, 2004; Abd El Samie and Sadek, 2001; Gorski and Ghodeif, 2000; Tantawi et al., 1998; Gat and Issar, 1974; Mazor et al., 1973). Seawater mixing index was used to estimate the relative degree of seawater mixing in the principal aquifers in the study area, this index is based on four major ionic constituents concentrations in seawater (Na, Mg, Cl, and SO4) as follow.

�� = � � �(��)

�(��) + � �

�(��)

�(��) + � �

�(��)

�(��)+ � �

�(��4)

�(��4)

a, b, c, and d are constants denote the relative concentration proportion of Na, Mg, Cl, and SO4 in seawater, respectively (a = 0.31, b = 0.04, c = 0.57, d = 0.08); C is the measured concentration of water samples in mg/L and T is the regional threshold values of the considered ions estimated from the interpretation of cumulative probability curves (Mondal and Singh, 2011).

Fig. 3: Map showing the location of groundwater samples of the main aquifers in Southern Sinai, Egypt.

Results and Discussion 1. Groundwater Geochemistry:

The study area characterized by a wide range of groundwater salinity. The groundwater salinity ranges between 211 mg/L at to 53347 mg/L. The groundwater in different aquifers has been classified according to the salinity into; fresh water (< 1000), brackish water (1000 to 10,000), saline water (10,000 to 100,000) and brine water (> 100,000) (Freeze and Cherry, 1979) (Table 1, Figures 4 and 5). In general the highest groundwater salinity in south Sinai aquifers has been recorded in the Miocene aquifer, while the most fresh groundwater in the upper cretaceous aquifer.


943

Fig. 4: Map showing groundwater classification based on the groundwater salinity (mg/L) according to Freeze and Cherry, (1979).

Fig. 5: Box plots showing the salinity (mg/L) of groundwater samples in the main aquifers located Southern Sinai, Egypt.

The lower groundwater salinity is locally recorded at the upstream portion of watersheds basins draining toward the Gulf of Suez and Aqaba draining system. However higher groundwater salinity is recorded locally along the coastal zones and close to the desalination plants in Sharm El Sheikh area. The most fresh groundwater samples represented by the U. Cretaceous, L. Cretaceous (Nubian sandstone) Quaternary, and Precambrian aquifers located in St. Catherine mountains, El-Qaa plain at El-wadi village, and in the upstreams of Dahab (Saal and Nassab), Surd and Gharandl basins. This


944

mainly attributed to the implications of recent recharge comes watershed of south Sinais' aquifers. The areas have lower groundwater salinity could be considered as promising localities for sustainable development. Brackish groundwater type is represented by the Quaternary, the Miocene, the Upper Cretaceous, the Lowe Cretaceous (Nubian sandstone), and the Precambrian aquifers located in the coastal plains, downstreams of Sudr, Warden and Watir basins as well as some localities of El-Qaa plain, and in the north of the study area at Nekhel and Hasana areas. The brackish groundwater zones are considered a favorable locality for low-cost groundwater desalination. The saline groundwater represented in the Quaternary, Miocene, and L.Cretaceous (Nubian sandstone) aquifers located along the coastal plain of the Suez gulf and Aqaba Gulf. The hypersaline groundwater has been recorded in Sharm El Shiekh and Nabaq areas are mainly due to the impact of brine disposal deeper into the coastal aquifer (Isawi et al., 2016). Table 1: Water chemistry data for groundwater samples tapping different aquifers located Southern

Sinai, Egypt.

PH TDS Ca Mg Na K CO3 HCO3 SO4 Cl δ 18O δ D

Quaternary (No of samples: 319)

Min 6.2 314.2 18.0 1.2 30.2 0.6 0.0 0.0 22.9 26.6 -7.3 -47.9

Max 8.8 35622.0 1900.0

1219.6

9650.0 530.0 24.0 317.3 5061.0 20661.3 6.9 22.5

Mean 7.8 3814.0 325.6 157.3 809.9 21.2 1.4 144.7 769.5 1628.7 -3.7 -22.8

Std. Deviation 0.4 4278.3 268.1 163.3 1130.9 38.3 4.0 54.2 659.5 2289.8 2.4 12.5

Miocene (No of samples: 65)

Min 6.4 755.0 70.5 42.2 98.0 9.8 0.0 76.3 180.0 171.0 -5.9 -31.8

Max 8.3 75487.8 3600.0

2478.6

24000.0 550.0 21.4 326.8 7093.0 40600.0 2.2 12.5

Mean 7.2 48624.5 907.8 1365.8

15187.2 356.6 0.4 128.3 4162.5 26570.7 -0.4 -3.0

Std. Deviation 0.4 21667.9 849.2 626.3 7072.0 159.8 2.9 41.3 1928.4 12067.0 2.7 17.0

U. Cretaceous (No of samples: 5)

Min 7.4 538.0 40.8 24.6 60.0 5.0

127.9 138.0 118.0 -6.7 -34.2

Max 8.3 2445.0 182.2 139.9 510.0 11.0

319.8 610.0 743.0 -5.1 -29.3

Mean 7.9 1386.4 94.0 78.4 248.8 7.9

205.4 351.6 393.6 -5.9 -31.6

Std. Deviation 0.4 936.2 53.7 48.3 217.5 2.7

84.4 197.2 318.5 0.6 2.2

L. Cretaceous (No of samples: 44)

Min 6.6 356.0 60.1 24.0 55.0 2.0 0.0 87.2 54.7 81.0 -9.6 -72.9

Max 8.3 8192.0 594.0 354.0 1794.0 87.6 16.0 399.3 2218.0 3768.0 -4.0 -23.6

Mean 7.9 2362.4 222.6 125.8 428.8 24.6 8.8 199.4 593.7 862.1 -7.2 -48.8

Std. Deviation 0.3 1664.5 144.5 84.0 349.0 18.5 8.1 80.1 481.3 787.1 1.3 11.1

Precambrian (No of samples: 18)

Min 6.8 211.0 12.0 7.0 13.0 1.5 0.0 101.0 2.0 26.0 -5.6 -29.5

Max 8.0 3412.5 450.9 216.3 581.4 102.9 20.7 262.8 1540.2 951.8 -1.0 -5.5

Mean 7.3 1253.3 151.5 66.8 219.7 24.3 4.4 182.2 465.2 309.0 -3.8 -20.7

Std. Deviation 0.4 1020.6 142.1 60.2 198.5 33.6 8.1 46.4 498.9 311.0 1.3 6.6

Sea water (Mean) 7.27

46410 528.78

1499.09

12785.16

456 0 103.99 3319.35 23763 1.6 9.9

Rain water (Mean)

7 48 7.15 0.61 23.15 20 0 14.54 6.34 0.15 -4.6 -19.2

2. Indicators of groundwater salinization

The rNa/rCl (meq/L) ratio is used to discriminate between the origin of groundwater, where meteoric water have a ratio more than unity while the rNa/rCl value less than unity indicates the contribution of marine sediments and/or seawater mixing (Figures 6). The ratio could reach unity due to the mixing of seawater and freshwater (Ivanov et al., 1968). The rNa/rCl ratio of the Quaternary, Eocene, Miocene, and L. Cretaceous aquifers in the coastal areas record values less than unity, reflecting the contribution of marine origin, while the all groundwater samples located in the inland areas have values of rNa/rCl more than unity reflecting meteoric origin and the contribution of recent recharge comes from precipitation.

In Figure 7, the graphical relation between chloride and electrical conductivity (EC) (kelly, 2005) shows three distinctive groundwater zones. The first zone is groundwater that has low salinity; the second zone characterizing groundwater that has relative mixing with seawater and the third zone has a groundwater salinity greater than seawater and reveal the impact of reject brine injection deeper into the groundwater aquifer. The Precambrian and the inland Quaternary aquifers has no great


945

influence of seawater mixing, while the Quaternary and the Miocene coastal aquifers are mostly influenced by seawater intrusion.

Fig. 6: Binary diagram of Na/Cl versus Cl (meq/L) for the groundwater samples in the study area.

Fig. 7: Chloride vs Electrical conductivity for the groundwater samples in the study area.


946

3. Statistical Analyses and Groundwater Mixing Sources

The seawater mixing index (SWMI) gives good indication of the mixing with different waters as well as the origin of groundwater. When the calculated SWMI value is greater than unity, the water may be considered to obviously record the effect of seawater mixing (Han et al., 2015). The estimation of the inflection points corresponding to regional threshold Ti values (Sinclair, 1974) for the major ions (Na, Mg, SO4, and Cl) were calculated depending on the statistical cumulative probability curves for the principal aquifers in the study area (Figure, 8a). According to SWMI values (Table 2), it is found that the groundwater samples can be classified into three groups (Figure, 8b), group A which have SWMI values less than 1 and TDS less than 16800 mg/L. This values have been detected in the groundwater aquifers located mainly in the upstream portions of different basins including the Quaternary, Eocene, L. Cretaceous, U. Cretaceous, and Precambrian aquifers. Therefore, the main sources for the groundwater salinization in these aquifers are restricted to the water-rock interaction and leaching of marine origin. Group B; characterizing coastal groundwater aquifers located in the downstreams, that have SWMI values more than 1 and groundwater salinity ranges between 4360 to 38957 mg/L which is close to seawater reflecting possible seawater intrusion and/or leaching of marine deposits. Group C, characterizing groundwater aquifers located in Sharm El Shiekh area and Nabaq area, that have SWMI values greater than 10 and groundwater salinity exceeding the seawater (more than 47000 mg/L), reflecting the impact of brine water disposal from desalination plants in the Miocene aquifer. According to the SWMI values we can identify the locations which can be influenced by seawater intrusion (Figure, 8.c), this map reflected the sea water intrusion is clearly appeared in the Quaternary aquifer at Nuwbiaa city and in the Miocene aquifer at Nabq area. The groundwater samples have SWMI greater than one and located in the upstream portion indicating the impact of leaching of marine deposits.

Table 2: Sea water mixing index (SWMI) and reflection point (R) values for groundwater samples

tapping different aquifers located Southern Sinai, Egypt.

Item Reflection point (R) SWMI Min Max Mean

Quaternary (No of samples: 319)

Na 1268

0.019 5.32 0.49 Mg 256

SO4 1368

Cl 4430

Miocene (No of samples: 65)

Na 425

0.23 45.5 29.1 Mg 137

SO4 359

Cl 896

L. Cretaceous (No of samples: 44)

Na 678

0.089 2.43 0.62 Mg 224

SO4 1250

Cl 1450

Precambrian (No of samples: 18)

Na 643

0.019 0.078 0.28 Mg 182

SO4 1649

Cl 1449


947

Figure 8a. Statistical normalized probability curves for Na+, Mg2+, Cl- and SO4

2- for groundwater samples in the study area (S.W sea water, R.W rain water. R reflection point).

0

2000

4000

6000

8000

10000

12000

14000

0 0.2 0.4 0.6 0.8 1

Na

(mg/L

)

Cumulative probability

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

0 0.2 0.4 0.6 0.8 1

Cl-

(mg/L

)


0

500

1000

1500

2000

2500

3000

0 0.2 0.4 0.6 0.8 1

Mg

(mg/

L)


0

5000

10000

15000

20000

25000

30000

0 0.2 0.4 0.6 0.8 1

Na

(mg/

L)


0

4000

8000

12000

16000

0 0.5 1

Na

(mg/

L)


0

5000

10000

15000

20000

25000

0 0.5 1

Cl-

(PPm

)


0

1000

2000

3000

4000

5000

6000

0 0.5 1

SO

4 (m

g/L)


0

200

400

600

800

1000

1200

1400

1600

0 0.5 1

Mg (m

g/L

)


0

1000

2000

3000

4000

5000

6000

7000

8000

0 0.2 0.4 0.6 0.8 1

SO

4 (m

g/L

)


0

200

400

600

800

1000

1200

1400

1600

0 0.2 0.4 0.6 0.8 1

Mg

(mg/L

)


0

5000

10000

15000

20000

25000

0 0.2 0.4 0.6 0.8 1

SO

4(m

g/L

)


0

5000

10000

15000

20000

25000

0 0.2 0.4 0.6 0.8 1

Cl-

(mg/L

)


0

2000

4000

6000

8000

10000

12000

14000

0 0.5 1

Na

(mg/L

)


0

200

400

600

800

1000

1200

1400

1600

0 0.2 0.4 0.6 0.8 1

Mg

(mg/L

)


0

500

1000

1500

2000

2500

3000

3500

0 0.5 1

SO

4(m

g/L

)


0

5000

10000

15000

20000

25000

0 0.5 1

Cl-

(mg/

L)



948

Fig. 8b: Relationship between the seawater mixing index and groundwater salinity (TDS, mg/L) for groundwater tapping the main aquifers in Southern Sinai, Egypt

Fig.8 c: Spatial distribution of the SWMI for principle aquifers in Southern Sinai, Egypt.

4. Endogenous Salinization Processes

This relation is one of the most important relations to illustrate the natural mechanism that change the groundwater chemistry, including rock weathering, evaporation and participation dominance. According to the relationship between the groundwater salinity and the (Na+/[Na+ + Ca+2]) ratio (Figure. 9), the groundwater could be classified into four unique classes (Gibbs, 1970). The groundwater Class A; representing fresh groundwater sample of the Quaternary aquifer located in


949

the upstream of Wadi Dahab Basin at Saal Sub-Basin indicating the superior groundwater replinishement and the rock weathering is the main controlling factor affecting the groundwater salinity. The groundwater Class B; plotted into the marginal area dominating the rock weathering and closer to the zone dominating evaporation-precipitation. Class B represents the watershed aquifers of the Quaternary, U. Cretaceous, L. Cretaceous (Nubian sandstone), Carboniferous, Cambrian and Precambrian. These aquifers are mainly located in St. Catherine mountains, El-Qaa plain (El-wadi village), upstream of Sudr, Wadi and Gharandl basins. In Gibbs diagram (Figure. 9) the coastal groundwater samples of the Quaternary aquifer (Class C) are plotted close to the precipitation and evaporation dominace region. Class D; is representing the Miocene coastal groundwater aquifer in Sharm El Shiekh area, that has been plotted in the upper right side and has salinity exceeding the seawater samples indicating the impact of seawater intrusion and mixing with disposal of high saline reject water comes from the desalination plants.

Fig. 9: Gibbs plot explains groundwater chemistry and geochemical process in the study area.

The Cl and Br ions behave conservatively in potable groundwater which leads to that the Cl/Br ratios remain unaltered because these ions have varied abundances in natural fluids and solids (Davis et al., 1998). Recently, many studies used Cl/Br ratios to identify the groundwater flow, to determine the main source of groundwater salinization and to evaluate the seawater intrusion in coastal aquifers (Fontes et al., 1986; Cartwright et al., 2006; Han et al., 2011). Moreover, Cl/Br ratio has been used to distinguish the influence of groundwater contamination from wastewater sources and other anthropogenic impact (Davis et al., 1998; Katz et al., 2011; McArthur et al., 2012; Samantara et al., 2015) and identification of the origin of salinization in groundwater (S´anchez-Martos et al., 2002; Kim et al., 2003; Alcala and Custodio, 2004; Alcala and Custodio., 2008; Skrzypek et al., 2013; Li et al., 2016; Eissa, et al., 2016 and Ouhamdouch, et al., 2017).


950

In Figure 10a, the Quaternary, the L. Cretaceous and Precambrian aquifers show positive correlation coefficients (R ranges from 0.42 to 0.79) between the concentration of dissolved chloride and bromide ions in groundwater. In Figure 10b, the Quaternary, L. Cretaceous and Precambrian groundwater samples are plotted upper left side on the mass balance mixing line between the recharge and seawater, reflecting the main source of groundwater mineralization is leaching and dissolution of aquifer matrix (Alcala and Custodio., 2004). Additionally, that indicating insights for high potential recharge from the annual precipitation at El Wadi, St. Catherine, Saal, Nassab, Sudr, Gharandl basins and El-Qaa plain (El Wadi village). The high Cl concentrations with approximately low values of Cl/Br ratio (C) reflects the impact of marine origins (Alcala and Custodio, 2008) and/or relative percentages of seawater intrusion in the coastal aquifers with some agricultural activities. The Br versus Cl (meq/l) plot presents a positive correlation for the Miocene groundwater located in Sharm El Shiekh and Nabaq areas, has a correlation coefficient value close to 1 (R = 0.91), indicating the same origin of groundwater salinization, where the reject brine disposal is the main source for groundwater salinization.

Fig. 10 a: Br vs Cl (meq/l) Plot for principle aquifers in South Sinai.


951

Fig.10 b: Cl/Br ratios vs Cl (mg/L) Plot for principle aquifers in South Sinai.

5. Delineate Recharge Zones Using Environmental Isotopes:

The environmental stable isotopes have been used to delineate the groundwater recharge and salinization sources in coastal arid aquifers worldwide (Eissa et al., 2018). According to the isotopic content of the δ 18O and δ 2H, the groundwater in the investigated aquifer can be classified into four groups. The Group A; has δ18O ranges between -10 and -6 % VSMOW, which are more depleted compared with the isotopic print of the recent precipitation in South Sinai (Eissa et al., 2013). These water reflects paleo-groundwater where the groundwater samples have plotted close to the Global Meteoric Water Line (GMWL) (Craig, 1961). This group represent the U. Cretaceous and the L. Cretaceous (Nubian sandstone) aquifers. The Group B, have δ 18O ranges between -6 and -2 %VSMOW, and plotted between Global Meteoric Water Line (GMWL) and the Mediterranean Meteoric Water Line (M.MWL) (Gat et al., 1969) closed to the recent preciptation. This group represent groundwater samples tapping the Quaternary, U. Cretaceous, L. Cretaceous, and Precambrian aquifers. The range of the δ 18Oand δ 2H indicate the contribution of the recent replenishments and sustainable recharge for these aquifers. Group C, characterized by the enrichment of δ 18O and δ 2H values and aligned on the evaporation trend line and along the sea water mixing line. This group is mainly represent by the coastal Quaternary and the inland Miocene aquifers. Group D, specified by high δ 18O and δ 2H values reflected the influence of disposal of reject of desalination plants on the Miocene aquifer in Nabaq area.

The relation between δ18O and d-excess was used to predict the effect of evaporation processes on the isotopic composition of groundwater samples as well as the paleo climatic conditions during the precipitation time. In Figure 12, the L. Cretaceous aquifer exhibits higher value of the d-excess and the most depleted δ18O content reflecting a paleo-water source with cooler climate and noneffect of evaporation during the recharge processes. The Quaternary and Miocene groundwater, exhibits lower d-excess values and enrichment with the δ18O content indicating the dominance of evaporation processes (El-Sayed et al., 2011).


952

Fig. 11: δ2Hvs δ18O for the groundwater tapping the principle aquifers in Southern Sinai, Egypt.

Fig. 12: The d-excess vs δ 18O for the groundwater tapping the principle aquifers in Southern Sinai,

Egypt.


953

In Figure 13, the relation between δ 18O and chloride (mg/L) indicates that the groundwater samples of the U. Cretaceous aquifer (group A) are not affected by evaporation processes where the main source of aquifer salinization is leaching and dissolution processes (water-rock interaction) of the aquifer matrix. The L. Cretaceous and Precambrian aquifers are moderately influenced by evaporation processes and the source of salinity of these aquifers is due to the evaporation, and dissolution processes inside the aquifer. The salinity source of the Quaternary aquifers in Watair basin (Group D) is due to the effect of strong evaporation and mixing with seawater. The Miocene aquifer in Nabq area are mostly influenced by the aquifer salinization due to the disposal reject of the desalination plants (Group D).

Fig. 13: δ 18O vsCl (mg/L) the groundwater tapping the principle aquifers in Southern Sinai, Egypt.

Conclusions

The South Sinais' watersheds drain East toward the Gulf of Aqaba and West toward the Gulf of Suez. The area comprises five main aquifers which considered the main source for potable water. The groundwater geochemistry and isotopic data showed different salinization and recharge sources for different aquifers. The isotopic signature of different groundwater aquifers in the South Sinai's were utilized to divide the groundwater into four distinct groups. The group A represent the lower Cretaceous groundwater which has been replenished during paleo-geological Pleistocene time under coolar climatic condition and still receiving considerable amount of the recent recharge. The lower Cretaceous aquifer at the upstream portion of Watair basin is considered good aquifer for sustainable management and the aquifer could be managed sustainably. Group B and Group C are characterizing the Quaternary and the Basement aquifers, where the isotopic signature of δ2H and δ18O in most areas are close to the recent precipitation and have brackish water type indicating considerable mixing with seawater at the downstream portions of different basins and slight evaporation processes. These two groups comprises Saint Catherine, Upstream of Dahab Basin and El Tour areas, where the groundwater aquifers receives considrable amount of the annual precipitation and runoff water comes


954

from the upstream watershed of El Egma and El Tih Plateau. On the other hand, the coastal groundwater aquifers located in the downstream are characterized by high groundwater salinization due to mixing with the seawater. The groundwater geochemistry and isotopes indicated the imapct of anthropological impact of injecting brine waste comes from the desalination plants at Sharm El Shikh and Nabaq area deteriorates the groundwater quality in the Miocene coastal aquifer. The regional studies in south Sinai's groundwater aquifers delineates the promising areas receives considerable and sustainable groundwater recharge and sound an alarm for aquifer deterioration due to over pumping and anthropological activities. References Abd el Samie, S., and M. Sadek, 2001. Groundwater recharge and flow in the Lower Cretaceous

Nubian Sandstone aquifer in the Sinai Peninsula, using isotopic techniques and hydrochemistry. Hydrogeology Journal, 9(4): 378–389.

Abdel Zaher, M., M. El Nuby., E. Ghamry., K. Mansour., M. N. Saadi., and H. Atef, 2014. Geothermal studies in oilfield districts of Eastern Margin of the Gulf of Suez, Egypt. NRIAG Journal of Astronomy and Geophysics, 3(1): 62–69.

Abouelmagd, A., M. Sultan., N. C. Sturchio., F. Soliman., M. Rashed., M. Ahmed., and K. Chouinard, 2014. Paleoclimate record in the Nubian Sandstone Aquifer, Sinai Peninsula, Egypt. Quaternary Research, 81(01): 158–167.

Alcalá, J and E. Custodio, 2004. Use of the Cl/Br ratio as a tracer to identify the origin of salinityin some coastal aquifers of Spain. 18 SWIM. Cartagena, Spain, 481 – 497.

Alcalá, J., and E. Custodio, 2008. Using the Cl/Br ratio as a tracer to identify the origin of salinity in aquifers in Spain and Portugal. Journal of Hydrology, 359(1-2): 189–207.

Ben Hamouda, M. F., J. Tarhouni., C. Leduc., and k. Zouari, 2010. Understanding the origin of salinization of the Plio-quaternary eastern coastal aquifer of Cap Bon (Tunisia) using geochemical and isotope investigations. Environmental Earth Sciences, 63(5): 889–901.

Caragnano, A., F. Colombo., G. Rodondi., and D. Basso, 2009. 3-D distribution of nongeniculate corallinales: a case study from a reef crest of South Sinai (Red Sea, Egypt). Coral Reefs, 28(4): 881–891.

Carol, E., E. Kruse., and J. Mas-Pla, 2009. Hydrochemical and isotopical evidence of ground water salinization processes on the coastal plain of Samborombón Bay, Argentina. Journal of Hydrology, 365(3-4): 335–345.

Cartwright, I., R. T. Weaver., and K. L. Fifield, 2006. Cl/Br ratios and environmental isotopes as indicators of recharge variability and groundwater flow: An example from the southeast Murray Basin, Australia. Chemical Geology, 231(1-2): 38–56.

Clark, I., and P. Fritz, 1997. Environmental isotopes in hydrogeology.CRC Lewis Publishers, New York, p 328

Craig, H, 1961. Isotopic variations in meteoric waters. Science, 133: 1702-1703. Dames., and Moore, 1985. Sinai development study, phase 1, final report, water supplies and cost.

Vol 5. Rep submitted tothe Advisory Committee for Reconstruction Ministry of Development, Cairo.

Davis, N., D. Whittemore., and J. Martin, 1998. Uses ofchloride/bromide ratios in studies of potable water. GroundWater 36 (2): 338–350.

De Montety, V., O. Radakovitch., C. Vallet-Coulomb., B. Blavoux., D. Hermitte., and V. Valles, 2008. Origin of groundwater salinity and hydrogeochemical processes in a confined coastal aquifer: Case of the Rhône delta (Southern France). Applied Geochemistry, 23(8): 2337–2349.

Eissa, M., M. Thomas., L. Hershey., M. Dawoud., G. Pohll., K. Dahab., and A. Shabana, 2013. Geochemical and isotopic evolution of groundwater in the Wadi Watir watershed, Sinai Peninsula, Egypt. Environmental Earth Sciences, 71(4): 1855–1869.

Eissa, M., M. Thomas., G. Pohll., O. Shouakar-Stash., L. Hershey., and M. Dawoud, 2016. Groundwater recharge and salinization in the arid coastal plain aquifer of the Wadi Watir delta, Sinai, Egypt. Applied Geochemistry, 71: 48–62.

Eissa, M, 2018. Application of Multi-Isotopes and Geochemical Modeling for Delineating Recharge and Salinization Sources in Dahab Basin Aquifers (South Sinai, Egypt). Hydrology, 5(3): 41.


955

El-Fiky, A, 2009. Hydrogeochemistry and Geothermometry of ThermalGroundwater from the Gulf of Suez Region, Egypt. JKAU: Earth Sci., 20 (2): 71-96.

El-Fiky, A, 2010. Hydrogeochemical Characteristics and Evolution ofGroundwater at the Ras Sudr-Abu Zenima Area, Southwest Sinai, Egypt. JKAU: Earth Sci., 21(1): 79-109.

El-Rayes, E., O. Arnous., and A. Aboulela, 2014. Hydrogeochemical and seismological exploration for geothermal resources in South Sinai, Egypt utilizing GIS and remote sensing. Arabian Journal of Geosciences, 8(8): 5631–5647.

El-Sayed, S., H. Sabet., and H. Ali, 2011. Appraisal Of Groundwater In El-Tur Area, Southwest Sinai, Egypt. isotope & rad. res., 43(3): 605-632.

Fontes, J., M. Yousefi., and B. Allison, 1986. Estimation of thelong-term groundwater discharge in

the Northern Sahara usingstable isotope profiles in soil water. Journal of Hydrology, 8: 315–327.

Freeze, R., and A. Cherry, 1979. Groundwater. Prentice Hall, Engle Wood Cliffs, 84. Gat, R., E. Mazor., and Y. Tzur, 1969. The stable isotope composition of mineral waters in the Jordan

Rift Valley, Israel. Journal of Hydrology, 7(3): 334–352. Gat, R., and A. Issar, 1974. Desert isotope hydrology: Water sources of the Sinai Desert. Geochimica

et Cosmochimica Acta, 38(7): 1117–1131. Gibbs, J, 1970. Mechanism controlling world water chemistry. Science, 170, 1088-1090. Gorski, J. and K. Ghodeif, 2000. Salinization of shallow water aquifer in El Qaa coastal plain, Sinai,

Egypt. In: Proceedings of 16th salt water intrusion meeting, Wolin Island, Poland. Han, D., C. Kohfahl., X. Song., G. Xiao., and J. Yang, 2011. Geochemical and isotopic evidence for

palaeo-seawater intrusion into the south coast aquifer of Laizhou Bay, China. Applied Geochemistry, 26(5): 863–883.

Han, D., V. Post., and X. Song, 2015. Groundwater salinization processes and reversibility of seawater intrusion in coastal carbonate aquifers. Journal of Hydrology, 531: 1067–1080.

Hereher, M. E, 2015. Assessment of South Sinai Coastal Vulnerability to Climate Change. Journal of Coastal Research, 316: 1469–1477.

Indu, S., S. Nair., P. Renganayaki., and L. Elango, 2013. Identification of Seawater Intrusion by Cl/Br Ratio and Mitigation through Managed Aquifer Recharge in Aquifers North of Chennai, India). JGWR, 2, 155 - 162.

Isawi, H., M. El-Sayed., M. Eissa., O. Shouakar-Stash., H. Shawky., and M. Abdel Mottaleb, 2016. Integrated Geochemistry, Isotopes, and Geostatistical Techniques to Investigate Groundwater Sources and Salinization Origin in the Sharm EL-Shiekh Area, South Sinia, Egypt. Water, Air, & Soil Pollution, 227(5).

Ivanov, W., and N. Plotanikova, 1968. The main genetic types of the earth’s crust minerals waters and their distribution in the USSR., Report of the 23rd .Session-I.G.G.,33.

Japan International Cooperation Agency (JICA), 1999. South Sinai Groundwater Resources Study in the Arab Republic of Egypt. Tokyo, Japan. 220. Katz, G., M. Eberts., and J. Kauffman, 2011. Using Cl/Br ratios and other indicators to assess

potential impacts on groundwater quality from septic systems: A review and examples from principal aquifers in the United States. Journal of Hydrology, 397(3-4): 151–166.

Kelly, D, 2005. Seawater intrusion topic paper (final), Island County: WRIA 6 Watershed Planning Process 1-30. Kim, Y., K. Lee., D. Koh., D. Lee., S. Lee., W. Park., and N. Woo, 2003. Hydrogeochemical and

isotopic evidence of groundwater salinization in a coastal aquifer: a case study in Jeju volcanic island, Korea. Journal of Hydrology, 270(3-4): 282–294.

Kora, M, 1995. An Introduction to the Stratigraphy of Egypt. Lecture notes, Geology Dept., Mansoura Univ, 116.

Leduc C., S. Ben Ammar., G. Favreau., R. Be., R. Virrion., G. Lacombe., J. Tarhouni., C. Aouadi., B. Zenati., N. Jebnoun., L. Michelot., and K. Zouari, 2007. Impacts of hydrological changesin the Mediterranean zone: environmental modifications andrural development in the Merguellil catchment (central Tunisia).HydrolSci J, 52: 1162–1178.


956

Li, J., Y. Wang., and X. Xie, 2016. Cl/Br ratios and chlorine isotope evidences for groundwater salinization and its impact on groundwater arsenic, fluoride and iodine enrichment in the Datong basin, China. Science of The Total Environment, 544: 158–167.

Mazor, E., A. Nadler., and M. Molcho, 1973. Mineral springs in the Suez Rift Valley Comparison with waters in the Jordan Rift valley and postulation of a marine origin. Journal of Hydrology, 20(4): 289–309.

McArthur, M., K. Sikdar., A. Hoque., and U. Ghosal, 2012. Waste-water impacts on groundwater: Cl/Br ratios and implications for arsenic pollution of groundwater in the Bengal Basin and Red River Basin, Vietnam. Science of The Total Environment, 437: 390–402.

Mondal, N., and V. Singh, 2011. Hydrochemical analysis of salinization for a tannery belt in Southern India. Journal of Hydrology, 405(3-4): 235–247.

Mook, G, 2001. Environmental isotopes in the hydrological cycle,Principles and applications. IHP-V,

technical documents inhydrology 39 (IV). UNESCO, Paris. Omara, S, 1972. An early Cambrian outcrop in southwestern Sinai, Egypt. N.JP. Geol. Palaeontol. 5:

306–314. Omran, A, 2013. Application of GIS and remote sensing for water resource management in Arid

area–Wadi Dahab Basin–South Eastern Sinai-Egypt (Case-study). Ph. D thesis, Universität Tübingen

Ouhamdouch, S., M. Bahir., and P. Carreira, 2017. Geochemical and Isotopic Tools to Deciphering the Origin of Mineralization of the Coastal Aquifer of Essaouira Basin, Morocco. Procedia Earth and Planetary Science, 17: 73–76.

Riguzzi, F., G. Pietrantonio., A. Piersanti., and S. Mahmoud, 2006. Current motion and short-term deformations in the Suez–Sinai area from GPS observations. Journal of Geodynamics, 41(5): 485–499.

Rosenthal, E., M. Zilberbrand., and Y. Livshitz, 2007. The hydrochemical evolution of brackish groundwater in central and northern Sinai (Egypt) and in the western Negev (Israel). Journal of Hydrology, 337(3-4): 294–314.

Saied, M, 2004. Geochemistry of Groundwater In Coastal Areas, South-Sinai Egypt. Ph.D. Thesis. Fac. Sci., Ain Shams Univ., Egypt.

Samantara, K., K. Padhi., K. Satpathy., M. Sowmya., and P. Kumaran, 2015. Groundwater nitrate contamination and use of Cl/Br ratio for source appointment. Environmental Monitoring and Assessment, 187(2).

Sánchez-Martos, F., A. Pulido-Bosch., L. Molina-Sánchez., and A. Vallejos-Izquierdo, 2002. Identification of the origin of salinization in groundwater using minor ions (Lower Andarax, Southeast Spain). Science of The Total Environment, 297(1-3): 43–58.

Shata, A, 1992. Watershed management of potential water resources and desertification control in Sinai’, Proc. of the 3rd Conf. on Geology of Sinai for Development, Ismailia: 273–280.

Skrzypek, G., S. Dogramaci., and P. Grierson, 2013. Geochemical and hydrological processes controlling groundwater salinity of a large inland wetland of northwest Australia. Chemical Geology, 357: 164–177.

Sinclair, A, 1974. Selection of threshold values in geochemical data using probability graphs. Journal of Geochemical Exploration, 3(2): 129–149.

South Sinai, 2012. South Sinai information Center and Decision Support, Statistical Manual 2012. Sultan, M., S. Metwally., A. Milewski., D. Becker., M. Ahmed., W. Sauck., F. Soliman.,N. Sturchio.,

E. Yan., M. Rashed., A. Wagdy., R. Becker., B. Welton, 2011. Modern re-charge to fossil aquifers: geochemical, geophysical, and modeling constraints. Journal of Hydrology 403: 14–24.

Tantawi, M., E. El-Sayed., and M. Awad, 1998. Hydrochemical and stable isotope study of groundwater in the Saint Catherine-Wadi Feiran area, south Sinai, Egypt. Journal of African Earth Sciences, 26(2): 277–284.

Williams, D, 2001. Anthropogenic salinization of inland waters. Hydrobiologia 466: 329–337. Zaghlool, E, 2006. Hydrochemical studies for the quaternary groundwater in El-Tor area and its

vicinities, South Sinai, Egypt. M. Sc thesis, faculty of science, Benha University.

Integrated Geochemical Indicators and Geostatistics to ... · Fig. 3: Map showing the location of...

Documents

Transcript of Integrated Geochemical Indicators and Geostatistics to ... · Fig. 3: Map showing the location of...