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Research Article
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Hydrochemical Processes and Metal Composition of Ain Umm-Sabah Natural Spring in Al-Hassa Oasis Eastern Province, Saudi Arabia |
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Ahmed A. Al-Naeem
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ABSTRACT
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This study was carried out to determine the hydro-chemical
processes and the metal concentration of spring water to evaluate its
suitability for irrigation and other purposes. A total of 10 water samples
were collected from Ain Umm Sabah at different times and from different
locations from the spring basin. EC (dS m-1), pH, temperature,
total cations (Na, Ca, Mg, K) and anions [Cl, CO3, HCO3,
SO4, NO3, Fluoride (F)] were determined. Some trace
and heavy metals (Al, As, Ba, B, Br, Mo, Ni, Si, Cd, Cu, V, Fe, I, Pb,
Mn, Zn, Sr, Se, Sb, La and Se were determined. The Spring water is classified
as C4S2 (high salinity with medium sodicity problem water). Chloride (Cl)
and nitrate (NO3) concentrations were higher than the permissible
limits according to World Health Organization Standards. The Ain Umm Sabah
water is Na-Cl dominant water and can create soil sodicity problems and
cause Na and Cl ion toxicity to plants if used for irrigation of sensitive
crops. The spring water is under-saturated (negative SI) with respect
to calcite, dolomite, gypsum, anhydrite, halite, fluorite and aragonite
and oversaturated (positive SI) with respect to goethite, siderite and
hematite minerals. The concentration of all the estimated trace metals
was within the permissible limits for its use as drinking water and other
purposes according to WHO. Since the spring water contains high concentration
of NO3, hence can not be used for drinking purposes without
prior treatment. The study findings suggest careful use and pumping of
water from the spring. Further studies are required on regular basis to
monitor the depletion in the spring water level and the temporal change
in water salinity.
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INTRODUCTION
Al-Hassa Oasis is situated about 60 km to the West
of the Arabian Gulf in the Eastern Province of Saudi Arabia. The total
land area is approximately 20000 ha. Its geographical location is between
49° 10´ and 49° 55` Eastern longitude and 25° 05` and 25°
40´ Northern latitude (Al-Taher, 1999) which is around 130-160 m above
sea level (Al-Barrak, 1993). An extreme maximum air-temperature of 51.3°C
was recorded at Hofuf in June 1983. Mean annual rainfall is about 70.3
mm (Al-Kuwaiti and Ahmed, 2003).
Natural water springs were widespread along the western
edge of the Oasis from south of Al-Hofuf to north of Al-Mutirifi village
and divided under four main groups. Three of these groups are located
within the jurisdiction of Al-Hassa Irrigation and Drainage Authority
(HIDA) and the fourth group is situated out of this organization. These
groups are over three main sectors i.e., Eastern, middle and Northern
sectors. Ain Umm Sabah was classified under third group and is located
south of Al-Mutirifi village. Previously, Al-Hassa Oasis was irrigated
by limited groundwater resources represented by a hundred water wells
and natural springs.
Al-Kuwaiti and Ahmed (2003) stated that the total water
discharge of free flowing springs was 10 m3 sec-1.
according to BRGM (1977a) and 15.2 m3 sec-1 as recorded
by HIDA in cooperation with Waste Water Authority and the Directorate
of Agriculture and Water. Leichtweiss-Institute Research Team (1978) reported
that the discharge of all free flowing water springs was 10.3 m3
sec-1.
Ain Umm Sabah is one of the major springs in the Al-Hassa
Oasis. Its geographical location is between 49° 35` eastern longitude
and 25° 28´ northern latitude (BRGM, 1977b). It is situated about
6 km north of Mubarraz and 2.5 km South-East of Mutairifi. The basin of
the spring is a square concrete pond having dimensions of 18x18 m. Possibly,
it is recharged through the broken and cracked rocks from the bottom of
the Neogene rocks. It was a natural artesian spring. Currently, water
from Ain Umm Sabah spring is being pumped through a well drilled upto
300 m depth. Water discharge of Ain Umm Sabah was 1.26 m3
sec-1 (Twitchell, 1944) and 0.145 m3 sec-1
(Wakuti Consulting Engineers, 1964).
Water salinity of the Ain Umm Sabah natural spring was
measured as 1536 mg L-1 in 1979 (Anonymous, 1984), 1540 and
1560 mg L-1 by Leichtweiss-Institute (1975, 1978), respectively,
1750 mg L-1 (top of Ghawar Structure) to 2200 mg L-1
(east of Shedgam Plateau) in 1978 and 1690 mg L-1 by Hussain
and Sadiq (1991) and 2579 mg L-1 by Al-Hawas (2002). The temporal
changes in water quality especially the total water salinity may be the
result of intensive pumping to meet water requirements for various uses
(Blaszyk and Gorski, 1981; Appelo and Postma, 1994).
The suitability of water for irrigation, drinking and
other purposes is determined by many factors such as the solubility constants
of different ions present in water coming through rock-water interaction
in the aquifer. Water may not be suitable for all purposes if certain
elements such as chloride, nitrates and other trace metals (Cr, Pb, Cu,
etc.) exceed the permissible limits according to APHO (1998). Montgomery
(1985) reported that 80% of world`s well water samples contain less than
50% chloride concentration. A strong relationship was found between human
health and the fluoride contents in water. Fluoride is well known for
its help in protecting tooth decay (Al-Shemi and Al-Minawi, 1988).
Also, the chemical reactions in water play a minor role
in influencing the blood heart vessels, in spite of main factors not be
specified yet (Montgomery, 1985). More than 80% world diseases were linked
with water deficiency (WHO, 1971).
The change in water quality of Neogene aquifer in the
recent years created some concern for its re-evaluation especially for
the Ain Umm Sabah natural spring for irrigation, drinking and other purposes.
The aim of the study was to determine and evaluate the hydrochemical processes
of water of Ain Umm Sabah natural spring and its suitability for irrigation
and drinking purposes.
MATERIALS AND METHODS
A total of 10 water well samples were collected from five different
locations of the basin of Ain Umm Sabah natural spring during 2006-2007.
The pH and EC of water were measured instantly at the time of sample collection.
The water samples were collected in sterile plastic bottles, acidified
with pure nitric acid, stored in an ice box and transported to the analytical
laboratory for chemical analysis. Each sample was filtered through 0.45
mm pore size filter paper, then divided into three portions, (1) for cation
analysis, (2) for anion determinations and (3) for some minor and trace
elements. The analytical methods used for the determination of cations
and anions were those described in USDA (1954) and Page (1982) and shown
in Table 1.
Table 1: |
Analytical methods
used to determine cations and anions in the study |
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The ratio of sodium to other major cations (Ca, Mg, K) is important to
maintain soil structure and determine Na ion toxicity to plants. Because
plants are sensitive to sodium when its concentration in irrigation waters
exceeds the permissible limits for normal plant growth. To assess the
magnitude of Na on soil exchange complex, sodium hazard is usually expressed
in terms of Sodium Adsorption Ratio (SAR). The SAR was calculated by the
following equation (Rogers and Lydon, 1994). The concentration of sodium,
magnesium and calcium ions in Eq. 1 is me L-1
(Wilcox, 1955).
The sodium adsorption percentage was determined by the
following equation.
The cation exchange phenomenon occurs when the ions absorbed on the surface
of the soil particle differ from those present in the soil solution. This
phenomenon continues until an equilibrium is reached between the cations
on the mineral surface and those in the water (Rump and Krist, 1992).
The appropriate method for assessing the exchangeable sodium in the Ain
Umm Sabah aquifer is to determine the Exchangeable Sodium Percentage (ESP)
values on the basis of the SAR of water using the following empirical
relationship between the SAR of water and the ESP (USDA, 1954):
Trace and heavy metals were analyzed using Inductively
Coupled Plasma, ICP (Moselhy et al., 1978), while Arsenic and Selenium
were determined using Activation Technique Neutron (Reeves and Brooks,
1978) and (Morgan and Ehmann, 1971). Fluoride (F) and the nitrate (NO3)
groups were determined Spectrophotometrically utilizing the disulphonic
acid and alizarin red-S with the Zirconium-Oxychloride Reagent.
Each water sample was run in triplicate and the mean
for 10 water samples was calculated. The discharge of Ain Umm Sabah was
measured by traditional method i.e., volume container and the stopwatch.
Saturation indices: Saturation Indices (SI) were calculated for the 10 water
samples from Ain Umm Sabah spring using the PHREEQC model developed by
Parkhurst (1995) to determine the thermodynamic equilibrium of spring
water with respect to solid phase of different minerals present in the
aquifer rock formation and their effect on water chemistry after dissolution
during rock-water inaction process.
RESULTS AND DISCUSSION
The total salinity ranged between 1699-1802 mg L-1 with
a mean value of 1764 mg L-1 at different locations at various
period of time (Table 2). The temporal change in water
salinity could be due to high rate of pumping water from the aquifer and
also to the depletion of water level in the aquifer of Ain Umm Sabah spring
area. The water salinity is low as compared to that reported by Al-Hawas
(2002). This would mean that the water salinity improved with time and
could be attributed to the recharge of the aquifer by the intrusion of
low salinity water from below the Neogene aquifer and the surrounding
area. However, according to USDA (1954) and Wilcox (1955) water classification
schemes, the water of the Ain Umm Sabah natural spring can be classified
as C4S2 i.e., very high salinity and medium sodicity hazard water. The
cation concentration order is Na followed by Ca > Mg > K and the
anion concentration order is Cl followed by SO4 > HCO3
> CO3. This shows that the Ain Umm Saba has Na-Cl dominant
ions water. Therefore, the water is not suitable for irrigation under
normal soil and water conditions (Yousef, 1999). Also if the Exchangeable
Sodium Percentage (ESP) exceeds the level of 15, soil structure deteriorates
very rapidly and crates drainage problems due to inadequate soil permeability
(Ayers and Westcot, 1985). The water could be used for irrigation on coarse
textured soils provided certain managementpractices such leaching requirements,
selection of semi-salt tolerant crops and provision of adequate drainage
are adopted (Hussain et al., 1994).
Additionally, the use of spring water for irrigation
might create some sodicity problem in fine textured soils which could
be mitigated by applying appropriate amount of soluble calcium amendments
such gypsum, calcium chloride etc if the indigenous gypsum is not adequately
present in the soils under irrigation. This water can be used on coarse
textured (sandy) soil or organic soils having adequate drainage facilities
(Hussain et al., 1994).
The fluctuation is water salinity of Ain Umm Saba could
be attributed to the intrusion of fresh groundwater from the surrounding
water bearing aquifers or recharge of Neogene aquifer during the heavy
rainy season. There is also possibility that excess pumping during peak
water requirement period might have extracted water from the Al-Khobar
aquifer below the Neogene aquifer where the water salinity is less than
the Neogen aquifer thus causing fluctuation in water salinity either high
or low depending upon the rate of pumping water from Ain Umm Sabah spring.
Comparison of metal composition of Ain Umm Saba water with WHO standards:
Table 3 shows that the Cl concentration in Ain Umm Sabah water (966
mg L-1) was higher than the WHO (1971) permissible limits of
250 mg L-1 for drinking water and 600 mg L-1 as
the upper limit of Cl concentration acceptable for other activities.
The concentration of NO3 ion is slightly higher
in the water of Ain Umm Sabah natural spring as compared to the WHO (1993)
permissible limits (Table 3). This could be attributed to the application
of inorganic fertilizers containing appreciable amount of nitrogen elements
and the biological activities taking place in the agricultural farms.
These pollutants may stimulate the digestive, urinary and intestinal systems
in human being upon consumption of this water.
Table 4 shows the concentration of different ions on
percent basis. The high Cl concentration in the water of Ain Umm Sabah
spring accounts for 56% of the total cations and is in agreement with
the reported Cl
Table 2: |
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Table 3: |
Comparison of ions concentration
in the water of Ain Umm Sabah with the ion concentration permissible
by World Health Organization (WHO, 1971) |
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Table 4: |
Comparison of concentration
(mg L-1) of different ions on percent basis with the
WHO Standards |
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Table 5: |
Mean metal concentration (mg L-1)
of water of Ain Umm Sabah spring in Al-Hassa, Eastern Province as
compared to the WHO (1993) standards |
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Source = EEC (European
Countries Guidelines) |
concentration of Montgomery (1985) who found that the
chloride concentration is less than 50% in approximately 80% of world
water samples. The sodium (Na) ion concentration was ranked second (25%).
Table 5 shows the mean concentration of heavy metals
in the water of Ain Umm Sabah. In general, the concentration of all the
heavy metals was within the permissible limits of WHO (1993) standards.
The fluoride (F) concentration of spring water was higher than that reported
by McClure (1982) and Murray (1976) who found its range between 0.5-1
mg L-1. Therefore, it can be stated that the water of Ain Umm
Saba is safe for drinking purposes with respect to F concentration. Furthermore,
Table 6: |
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high concentration of Silicon ions of water may reflect
the composition of the Ain Umm Sabah`s aquifer rocks.
The discharge of Ain Umm Sabah natural spring was measured
using traditional method (plastic container of known volume and the stopwatch).
Currently, its discharge is 84 L sec-1 (0.084 m3 sec-1)
and the depth of well in the spring is more than 300 m. The temporal variation
in the spring discharge might possibly affect the water salinity due to
the radius of influence during pumping.
Temporal change in Ain Umm Sabah natural spring water: The results
of Table 6 indicate that Na, Cl, HCO3 and
SAR of spring water showed increases, Ca ion and total water salinity
decreased while K remained unchanged when compared with the results of
Al-Hawas (2002). Overall the spring water showed improvement with the
passage of time and could be attributed to higher pumping rate of water
from the aquifer.
Saturation indices: Saturation Indices (SI) were calculated for the 10 water
samples from Ain Umm Sabah spring using the PHREEQC model developed by
Parkhurst (1995). The spring water is under-saturated (negative SI) with
respect to calcite, dolomite, gypsum, anhydrite, halite, fluorite and
aragonite and oversaturated (positive SI) with respect to goethite, siderite
and hematite minerals. Actually, the SI is a measure of the thermodynamics
state of a solution relative to the equilibrium with a specified solid-phase
mineral. This shows that the spring water flow is capable of dissolving
the aquifer rock thus increasing its porosity and permeability consequently
affecting the water salinity.
CONCLUSIONS
The Spring water is classified as C4S2 (high salinity
with medium sodicity problem water). Chloride (Cl) and nitrate (NO3)
concentrations were higher than the permissible limits according to World
Health Organization Standards (WHO, 1993). The Ain Umm Sabah water is
Na-Cl dominant water and can create soil sodicity problems and Na and
Cl ion toxicity to plants if used for irrigation of sensitive crops. The
spring water is under-saturated (negative SI) with respect to certain
minerals (calcite, dolomite, gypsum, anhydrite, halite, fluorite and aragonite)
and oversaturated (positive SI) with respect to goethite, siderite and
hematite minerals. All the trace metals were within the permissible limits
for drinking and other purposes. Since the spring water contains high
concentration of NO3, hence can not be recommended its use
as drinking water without prior treatments. The study findings suggest
careful use and pumping of water from the spring. High concentration of
silicon ions provide good concept regarding the chemical settings of the
aquifer rocks of Ain Umm Sabah (Neogene aquifer) and may relate to the
faults arrangements nearby the Al-Gawar`s fold convex. In conclusion,
careful monitoring, appropriate irrigation scheduling and groundwater
pumping strategy should be developed to avoid over pumping of water and
minimize aquifer depletion in the Al-Hassa Oasis for sustainable irrigated
agriculture.
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REFERENCES |
1: Al-Barrak, S.A., 1993. Al-Hassa Oasis: Soils and agricultural land characteristics. Al-Hassa-Saudi Arabia, pp: 1-395.
2: Al-Hawas, I.A., 2002. Irrigation water quality evaluation of al-hassa springs and its predictive effects on soil properties. Pak. J. Biol. Sci., 5: 651-655. CrossRef | Direct Link |
3: Al-Kuwaiti, K. and S. Ahmed, 2003. Monitoring of hydrogeological neogene formation: Within Al-Hassa irrigation drainage project regime. Proceedings of the 6th Gulf Water Conference is Run in Conjunction with the 2nd Symposium on Water Use Rationalization in the Kingdom, March 8-12, Riyadh, King Saud University.
4: Al-Shemi, N. and M. Al-Minawi, 1988. Principles of Nutrition: Food Issues Evaluation. Arabic Bayan Publisher, Cairo, pp: 194-195.
5: Al-Taher, A.A., 1999. Al-Hassa: Geographical Studies. King Saud University, College of Arts, Riyadh, pp: 1-385.
6: APHA, AWWA and WEF., 1998. Standard Methods for the Examination of Water and Wastewater. 20th Edn., American Public Health Association/American Water Works Association/Water Environment Federation, Washington, DC., USA., ISBN-13: 9780875532356, Pages: 1220.
7: Anonymous, 1984. Annual report 1984. Water Resources Department, Al-Hassa Irrigation and Drainage Authority (HIDA), Hofuf, Saudi Arabia.
8: Appelo, C.A.J. and D. Postma, 1994. Geochemistry Groundwater and Pollution. A.A. Balkema Publishers, Leiden, The Netherlands, pp: 311-313.
9: Ayers, R.S. and D.W. Westcot, 1985. Water quality for agriculture. FAO Irrigation Drainage Paper No. 29, Food and Agriculture Organization of the United Nation, Rome, Italy.
10: Blaszyk, T. and J. Gorski, 1981. Ground-water quality changes during exploitation. Groundwater, 19: 28-33. CrossRef |
11: BRGM (Bureau Researches Geologiques Et Minieres), 1977. Hydro geological Study-Results of Chemical Analysis. Al-Hassa Development Project Groundwater resources study and Management programme- Final Report. Ministry of Agriculture and Water/ Groundwater Resources Development Department. Vol. III. Appendix 11-16.
12: BRGM , 1977. Groundwater resources study and management program of Al-Hassa area. Ministry of Agriculture and Water, Riyadh, KSA., pp: 57
13: Hussain, G. and M. Sadiq, 1991. Metal chemistry of irrigation and drainage waters of Al-Ahsa Oasis of Saudi Arabia and its effects on soil properties. Water Air Soil Pollut., 57-58: 773-783. CrossRef | Direct Link |
14: Hussain, G., M. Sadiq, Y.A. Nabulsi and O.J. Helweg, 1994. Effect of saline water on establishment of windbreak trees. Agric. Water Mange., 25: 35-43. CrossRef | Direct Link |
15: Leichtweiss-Institute Research Team, 1975. Water Resources of the Al-Hassa Oasis. Reports on the work of the Leichtweiss-Institute Research Team. Technical University Braunschweig. Al-Hofuf Agricultural Research Center. Al-Hassa. Saudi Arabia. Publication No. 13. Hofuf, 1975, pp: 1-69.
16: Leichtweiss-Institute Research Team, 1978. Water Resources of the Al-Hassa Oasis. Reports on the work of the Leichtweiss-Institute Research Team. Technical University Braunschweig. Al-Hofuf Agricultural Research Center. Al-Hassa. Saudi Arabia. Publication No. 22. Hofuf, 1978, pp: 43-44.
17: McClure, F.J., 1982. Fluoride in Drinking Water. Textbook Public Health Service Publication 825, Washington D.XC. USA., pp: 83.
18: Montgomery, J.M., 1985. Water Treatment Principles and Design. Inc., John Wiley and Sons, New York, USA., pp: 373.
19: Morgan, J.W. and W.D. Ehmann, 1971. 41 Mev Neutron Activation Analysis of Rocks and Meteorites. In: Activation Analysis in Geochemistry and Cosmochemistry, Brunfelt, A.O. and E. Steinnes (Eds.). Scandinavian University Books, Copenhagen, Denmark, pp: 468.
20: Moselhy, M.M., D.W. Boomer, J.N. Bishop, P.L. Diosady and A.D. Howlett, 1978. Inductively coupled plasma. ICP analysis. Can. J. Spectro., 23: 186-186.
21: Murray, J.J., 1976. Fluorides in Caries Prevention. 1st Edn., John Wiley and Sons Ltd., pp: 179.
22: Page, A.L., R.H. Miller and D.R. Keeney, 1982. Methods of Soil Analysis Part 2: Chemical and Microbiological Properties. 2nd Edn., ASA and SSSA, Madison, WI., USA., Pages: 1159.
23: Parkhurst, D.L., 1995. Users guide to PHREEQC: A computer program for speciation, reaction path, active transport and inverse geochemical calculations. USGS Water Resources Investigations Report, Vol. 33.
24: Reeves, R.D. and R.R. Brooks, 1978. Trace Element Analysis of Geological Materials. John Wiley, New York, USA., pp: 421.
25: Rogers, P. and P. Lydon, 1994. Water in the Arab World: Perspectives and Prognoses. Proceedings of the onference on Water in the Arab World, October 1-3, 194, Division of Applied Sciences, Harvard University, USA., pp: 369-369.
26: Rump, H.H. and H. Krist, 1992. Laboratory manual for the examination of water, Waste Waster and Soil. Library of Congress. Cambridge. Germany.
27: Twitchell, K.S., 1944. Water resources of Saudi Arabia. Geol. Rev., 34: 365-385.
28: United States Department of Agriculture (USDA), 1954. Diagnosis and Improvement of Saline and Alkali Soils. In: USDA Handbook, Richards, L.A. (Eds.). USDA., Washington, DC, USA., pp: 160.
29: Wakuti Consulting Engineers, 1964. Studies for the project of improving and drainage in the region of Al-Hassa. Saudi Arabia. Technical Report. Vol. No. 4, Siegen, West Germany, pp: 2.
30: Wilcox, L.V., 1955. Classification and use of irrigation water. U.S. Geol. Survey, Department of Agriculture, Washington, D.C., Circular No. 969, pp: 19.
31: WHO., 1971. International Standards for Drinking-Water. 3rd Edn., World Health Organization (WHO),, Geneva, Switzerland.
32: WHO, 1993. Revision of the WHO guidelines for drinking water quality. World Health Organization, Copenhagen.
33: Yousef, A.F., 1999. Soil and water: Instruments and methods and analysis. A Laboratory Manual, College of Agricultural and Veterinary Sciences, King Saud University, Riyadh, Saudi Arabia, pp: 1-462 (In Arabic).
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