International Journal of Scientific & Engineering Research, Volume 5, Issue 3, March-2014 490
ISSN 2229-5518
Ground Water Quality Assessment of Najaf City, Iraq.
Kasim Kadhim Alasedi
Abstract— Groundwater (GW ) quality in Najaf city were evaluated by determining Radon (222Rn), Heavy metals (HMs), and physiochemical parameters of twenty-seven different public GW on November 2013. The products showed that wells 222Rn concentrations ranged (317-5010) Bq/m3 were lesser than 11000 Bq/m3, a maximum contaminant level (MCL) proposed by United States Environmental Protection Agency (USEPA). hydrogen ion concentration (pH), Electrical conductivity (EC), Total dissolved solids (TDS), Salinity (Sal.),Turbidity (Tur.), Cations ( Na+, K+ ) and heavy metals (HMs); Cr, Co, Cu, Zn, Cd, and Pb for the groundwater under study has been examined. The results showed great variations among the analyzed samples with respect to their physical and chemical parameters. However, most values were higher the maximum permissible levels recommended by world health organization (W HO) drinking water standards. The harvests of metallic contents except Cu and Zn were higher the maximum permissible levels recommended by W HO drinking water standards. The quality assessment shows that in general, the GW in the study area is not entirely for direct drinking according to physiochemical properties and HMs concentrations, the water in the studied wells can be used for irrigational purposes.
Index Terms— Radon-222, Heavy metals (HMs), Physiochemical parameters, EPA, W HO, Groundwater, Najaf city.
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ATER quality is affected by natural processes and hu- man activities. It is often thought that the chemical com- position is the only factor involved. However, other con- ditions such as biological, physical, and radiological factors
should be considered when mentioning water quality [1, 2]. Radon (222Rn) is a naturally occurring radioactive, odorless,
and noble gas that is soluble in water produced by the decay of radium-226 (226Ra) within the natural decay chain of urani- um-238 (238 U). Radon which shows a half life of 3.8 days, em- anates from the surface of mineral grains by recoil and enters the water filled pore space of sediments and aquifers In recent years a lot of data about radon concentration in water has been collected for uranium prospecting, earthquake prediction, and groundwater exploration [3, 4]. Heavy metals (HMs) are ele- ments having atomic weights (63.54-200.59) and a specific gravity greater than 4.0 i.e. at least 5 times that the water. They exist in water of colloidal, particulate, and dissolved phases [5]. Among the wide variety of contaminants affecting water supplies, heavy metals deserve specific attention regarding their high toxicity even at law concentrations [6]. Water quali- ty is a major emerging concern throughout the world. Drink- ing water sources are threatened from contamination with far- reaching consequences for the health of children, economic, and development of communities.
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• Author for corresponding: Asst. Prof. Kasim K. Alasedi Ph.D degree in Analytical Chemistry. Head of Ecology Dep Faculty of Science, University of Kufa, P.O.Box :( 21), Kufa, Iraq. Research field: Analytical Chemistry and Environmental Pollution. E-mail: dr.kasim@yahoo.com qasimk.alasadi@uokufa.edu.iq Tel: (+964) 780-134-0055.
Groundwater is emerging as an essential and vital component of the life in Najaf city, support system today, the groundwater resources are being utilized for drinking, irrigation, and indus- trial purposes.
The Najaf area is located on the edge of western plateau of lower Mesopotamian at 50 km south of the ancient city of Babylon and 160 km southwest of Baghdad the capital of Iraq. Najaf lands is flat and leveled linked to Euphrates river water, it is higher in the southern portions of the desert areas, extend- ing to the Kingdom of Saudi Arabia. Twenty-seven well water samples were collected in November 2013. As it is indicated in Figure (1).
RAD-7 (Durridge company, USA) HR2RO with a 250mL glass sample bottle specially designed for222Rn measurement then slowly immersed into the bucket Figure2. Three water samples (A, B and C) were collected from each well (SR1R-SR27R) for the 222Rn analysis. For determining heavy metal concentrations, 50mL water were acidified with approximately 0.5ml of concentrat- ed HNOR3R (BDH) and passed through acid washed folded fil- ters, the filtrate was stored in acid washed polypropylene tubes until it was measured. Cr, Co, Cu, Zn, Cd and Pb in samples were detected by AA 6300 Flame Atomic Absorption Spectrophotometer, Shimadzu, Japan. Sampling and analytical techniques followed the suggestions by [7-9].
The Hydrogen Ion Concentration (pH), Electrical Conductivity (EC), Total Dissolved Solids (TDS), Salinity (Sal), and Turbidi- ty(Tur) of water samples were measured.
pH, EC, and TDS of water samples for chemical analysis were filtered then refrigerated at 4 0C before chemical analysis by
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International Journal of Scientific & Engineering Research, Volume 5, Issue 3, March-2014 491
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Fig. (1): Location of wells in Najaf city
multimeter type Crison MM40, Spain. Sampling and analyti- cal techniques followed the recommendations by [10, 11]. Sa- linity (Sal) was determined according to the procedure [10] measured by WTW, Germany. Turbidity (Tur) measured by turbicheck, Loribond, Germany. Sodium ion (Na+) and Potas- sium ion (K+) were determined [12] by flam photometer type
378 Elico, England.
Fig. (2): Rad-7 H2O assembly with a 250 ml water sample
Radon concentration was measured in 27 samples of wells collected all over the central core of Najaf city, radon concen- trations in the groundwater varied from 569Bq/m3 to
5010Bq/m3 within average mean value 1838Bq/m3 while lowest was found in groundwater number 18 as shown in figure(3). Higher concentrations were found in some parts south of the city which might be due to change of geological regime or ex- posure of younger granitic rocks associated with high abstrac- tion of wells. The overall concentrations of radon in well wa- ters are found to be far below the permissible limits.
Figure (3): 222Rn concentrations in water samples
pH is one of the most important operational water quality parameters. Substantial variations were recorded in the pH level; always the average values of pH in all sites were be- tween 6.91 to 7.60 within permissible limit. Electrical conduc- tivity (EC) and total dissolved solids (TDS) are a measurement of water's capacity for carrying electrical current and it is re- lated to the concentrations of ionized substance in the water. not citations The levels affected by EC of water are a direct function of TDS, from the results it was evident that the high- est value of 9330 µs/cm is obtained at S17 where as the lowest value of 3230 µs/cm is obtained at S3. Samples analyzed for TDS are showing values range 3200 to 6370ppm, as compared with the standard value which is 800ppm. The sampling loca- tion number is having higher TDS values in collected ground water samples. The fluctuations in EC correlated positively with the TDS which are indicators of polluted water. Suspend- ed matter of turbidity often includes mud, clay and slit. Tur- bidity values ranged from 0.27NTU to 10.8NTU. The maxi- mum permissible levels for turbidity from 0-10NTU [13]. The excessive turbidity in water causes problems with water puri- fication process such as flocculation and filtration, elevated turbid water is often associated with the possible of microbio- logical contamination as high turbidity makes it difficult to disinfect water properly [14] Salinity is a major water quality limitation on the environmental values (including potential beneficial uses) of groundwater. It is influenced by human action such as irrigation, disposal of waste waters, seawater
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International Journal of Scientific & Engineering Research, Volume 5, Issue 3, March-2014 492
ISSN 2229-5518
intrusion in response to excessive extraction from coastal aqui- fers, and the like. Excessive salinity in all groundwater may limit their use and therefore the productivity of lands reliant on bore water irrigation. Lower salinity levels were registered from 0.7ppt to 9.3ppt. These values were low compared with WHO guidelines values of 3-10ppt. Mean concentrations of sodium and potassium from the GW samples were 867 and
11.1ppm, respectively. Sodium is more mobile in soil than po- tassium and so it is used often as an indicator of human im- pacts to shallow GW. Sodium is also a common chemical in minerals. Like potassium, sodium is gradually released from rocks.
Table (1): Status of physiochemical parameters and heavy metals in ground water samples.
*Ref. [13]
The results of various heavy metals (HMs) analysis in groundwater samples (GWS) are listed in figure (4). During present investigation, chromium (Cr) ranged from ND to
0.398ppm in GWS. Most of GWS collected from the study area
contained Cr above permissible limit 0.05ppm recommended by WHO for drinking water. Cobalt (Co) usually occurs in association with other metals such as copper, nickel, manga- nese and arsenic. Small amounts are found in most rocks, soil, and surface and under GW, plants and animals. Cd concentra- tions ranged between ND to 0.1873ppm above permissible limits <0.001-0.002ppm recommended by WHO for drinking water. The concentration of Cu varied from the range of ND to o.1042ppm. GWS contained copper within permissible limits,
2ppm prescribed by WHO. The concentration of zinc (Zn)
ranged between ND to 0.3834ppm, and found within permis- sible limit 3ppm recommended by WHO for drinking water. Cadmium (Cd) metal was found in the range of ND to
0.0535ppm. The high concentration of Cd in some water samples of the study area may be attributed to the runoff from the agricultural fields where pesticides as well as cad- mium containing phosphates fertilizer have been used. GWS collected from the study area contained lead (Pb) ranged from 0.0033 to 0.0430ppm above permissible limit 0.01ppm recommended by WHO for drinking water. The possible source of Pb are combustion of gasoline, uses of lead arsenate as pesticide as well as its uses in lead pipe, paints, pigments and lead storage batteries [15].
Stations number
Figure (4): Concentrations of heavy metals in ground watesamples.
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Figure (5): Correlation of heavy metals and some physiochem- ical parameters.
The water quality of GWS had three objectives: (1) all results of radon concentrations were less than the allowed maximum values. (2) Physiochemical properties more than WHO guide- line values, these refer to inefficiency for drinking water. (3) Concentration of some toxic HMs such as Cr, Co, Cd and Pb were higher the maximum permissible levels recommended by world health organization (WHO) drinking water stand- ards.
The author would like to thank Asst. Prof. Dr. Mohammed J. Alhaydari, Dr. Faris J. Aldehadhawy and lecturer Muntather A. Tafar for supporting the project; I would also like to recog- nize Faculty of Science, University of Kufa, Iraq.
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