Scarcity of water, pollution load, political issues and rising population have drawn great attention for proper management of water resources such as groundwater in the 21st century. The evaluation of groundwater quality is a critical element in the assessment of water resources. The quality/potability of water that is consumed defines the baseline of protection against many diseases and infections. The present study aims to calculate the water quality index (WQI) by the analysis of seven physico-chemical parameters according to the National Sanitation Foundation (NSF) to assess the suitability of water for drinking, irrigation purposes and other human uses. In the present investigation, ten groundwater samples were collected from various parts of Seraidi municipality area located in the north-east of Algeria, Physico-chemical parameters such as pH, temperature, dissolved oxygen, phosphates, nitrates, turbidity and fecal coliforms were analyzed. The overall WQI values for all the samples were found to be in the range of 68–86, which reveals the fact that the quality of all the samples is only medium to good and could be used for drinking and other domestic uses only after proper treatment.

INTRODUCTION

Groundwater is a significant and crucial resource in many countries, and it commonly plays a key role as a water supply both for drinking and irrigation. In recent decades, water demand has dramatically increased, especially in developing countries, driven by population growth, improvements in living standards, development of industry, agriculture and urbanization (Llamas & Martínez-Santos 2005; WWAP 2009). This has led to increasing pressures on groundwater resources. Excessive abstractions of groundwater over past decades to meet these demands have resulted in serious problems: water table decline, groundwater quality degradation and damage to ecosystems. It is evident that the groundwater quality issue is as important as groundwater quantity for satisfying water needs (Karanth 1987; UNEP 2010; WWAP 2012). In Africa, groundwater is the major source of drinking water and its use for irrigation is forecast to increase substantially to combat growing food insecurity. Groundwater resources are unevenly distributed: the largest groundwater volumes are found in the large sedimentary aquifers in the North African countries of Libya, Algeria, Egypt and Sudan (MacDonald et al. 2012). Our estimates of groundwater storage do not consider water quality as there is currently insufficient data to make meaningful regional assessments for Africa (MacDonald et al. 2012). Undesirable natural concentrations of other parameters including iron, manganese and chloride can also be found in aquifers depending on local hydrogeological conditions. Contamination of groundwater by fecal coliforms and nitrate is common in urban areas from widespread and dispersed fecal effluent from on-site sanitation and leaking sewers (MacDonald et al. 2012). The quality of water is defined in terms of its physical, chemical, and biological parameters (Ketata et al. 2012). Ascertaining the quality is crucial before its use for various purposes such as drinking and agricultural, recreational, and industrial uses (Khan et al. 2003; Sargaonkar & Deshpande 2003).

The population of Seraidi municipality is served by two different supply systems, the first from Annaba and the second from groundwater abstraction. But it is served for only two hours per day and Seraidi suffers from a need for drinking water and its population is oriented to sources captured from groundwater on both sides of the municipality which have an irregular flow. However, the quality of this water is sometimes uncertain, given the failure of the existing sewerage network, which can directly affect the quality of the aquifer. In fact, the rugged topography of the municipality can make connection to the sewerage system of some urbanized sites hard, which encourages the use of septic tanks as the only means of escape for wastewater. On the other hand, for those inhabitants who discharge wastewater into the sewerage system, it ends in settling ponds, which are usually non-functional. From this perspective we were interested in the study to monitor the groundwater quality and the impact of the use of these waters on the health of the adjacent populations using the water quality index (WQI) of the National Sanitation Foundation (NSF).

The WQI was developed in the 1970s by the NSF for the purpose of summarizing and evaluating water quality trends and status (Dunnette 1979). The choice of the NSF-WQI was made because it summarizes data in a single index value in an objective, rapid and reproducible manner; the index value relates to a potential water use and evaluates the change in water quality between areas (Tyagi et al. 2013).

Location of the study area

The municipality of Seraidi is located at the north of Annaba city (in the north-east of Algeria), on cristallophyllian Edough massif heights about 850 metres above sea level, 13.3 km from Annaba, and extends over an area of 138 km2, between 36 ° 55′ 00″ north and 7 ° 40′ 00″ east. It is bordered at the north by the Mediterranean Sea, to the south by the municipality of El Bouni, to the east by Annaba city and at the west by the municipality of Oued El Aneb (Figure 1).
Figure 1

Location of the study area and the sampling points.

Figure 1

Location of the study area and the sampling points.

Hydrology

This region is influenced by a Mediterranean climate. The daily average temperatures vary between 7.51 °C in winter (January) and 24.8 °C in summer (August) with an average 15.49 °C. The annual average total precipitation during 2001–2011 was 978.93 mm/year. Spring water in the investigated area is the major source for drinking water and irrigational activities. The discharge of springs varied between 0.15 and 2.08 m3/s with an average discharge of 0.75 m3/s. Table 1 shows the spring water samples with their altitude and discharge in Seraidi municipality.

Table 1

The spring water samples with their altitude and discharge in Seraidi municipality

Spring no.Ident. no.Altitude (m)Discharge (m3/s)
GW1 762 0.23 
GW2 804 0.52 
GW3 820 0.15 
GW4 824 0.41 
GW5 778 0.7 
GW6 926 1.22 
GW7 847 0.27 
GW8 909 0.39 
GW9 669 2.08 
10 GW10 817 1.56 
Spring no.Ident. no.Altitude (m)Discharge (m3/s)
GW1 762 0.23 
GW2 804 0.52 
GW3 820 0.15 
GW4 824 0.41 
GW5 778 0.7 
GW6 926 1.22 
GW7 847 0.27 
GW8 909 0.39 
GW9 669 2.08 
10 GW10 817 1.56 

MATERIALS AND METHODS

Sampling

This study is an attempt to assess the quality of groundwater in the municipality of Seraidi. We use the WQI of the National Sanitation Foundation (NSF-WQI) on ten sampling points. Samples collected are located in: Ain Mouhkim (GW1), El Anser (GW2), Bouhadada (GW3), Dar Lekhel (GW4), Benjaballah (GW5), Allali Hocine (GW6), Parc Au Jeu (GW7), Mizeb (GW8), Dar Mzata (GW9), Ain Fedha (GW10). Sampling points were geo-located with the global positioning system to ensure consistency. Samples were collected during the dry season (June 2015).

The water samples were collected in 500 ml clean polyethylene bottles. At the time of sampling, the bottles were thoroughly rinsed two to three times with the groundwater to be sampled. In situ measurement was adopted to determine the unstable parameters, including pH, temperature, and dissolved oxygen (DO), using a multi-parameter ‘WTW. Multi 340i/SET’. Measurements of turbidity were carried out using a portable turbidity meter 2100P ISO robust field. The samples were stored in a low-temperature cooler (4° C) and transported to the laboratory, for analysis the other parameters, using a spectrophotometer DR 2800 HACH LANGE.

Total coliform bacteria were estimated in water samples by a multiple tube fermentation method called the most probable number (Collins & Lyne 1980).

Description of NSF-WQI – National Sanitation Foundation Water Quality index

Brown et al. (1970) developed a WQI with great rigor in selecting parameters, developing a common scale, and assigning weights for which elaborate Delphic exercises were performed (Bharti & Katyal 2011). This effort was supported by the NSF, which is why it is also referred to as NSF-WQI (Bharti & Katyal 2011). In this investigation we used the NSF-WQI for Algeria country (in North Africa). The proposed method for comparing the water quality of various water sources is based upon nine water quality parameters: temperature, pH, turbidity, fecal coliforms, DO, biochemical oxygen demand, total phosphates, nitrates and total solids (Tyagi et al. 2013). But in this present investigation, the parameters of total solids and biochemical oxygen demand have not been taken into consideration as there are no sources for these pollutants in the chosen study areas. Table 2 shows the physico-chemical and biological para­meters for calculating WQI and the parameters' weight.

Table 2

Physico-chemical and biological parameters and weight

ClassificationParameterUnitWeight
Physical Temperature °C 0.10 
Turbidity NTU 0.08 
Chemical DO 0.17 
Total phosphate mg/l 0.10 
Total nitrate mg/l 0.10 
pH  0.11 
Biological Fecal coliform CFU/100 ml 0.16 
ClassificationParameterUnitWeight
Physical Temperature °C 0.10 
Turbidity NTU 0.08 
Chemical DO 0.17 
Total phosphate mg/l 0.10 
Total nitrate mg/l 0.10 
pH  0.11 
Biological Fecal coliform CFU/100 ml 0.16 

The water quality data are recorded and transferred to a weighting curve chart, where a numerical value of Qi is obtained (Tyagi et al. 2013). The mathematical expression for NSF-WQI is given by the following expression: 
formula
1
where Qi = sub-index for ith water quality parameter; Wi = weight associated with ith water quality parameter; n = number of water quality parameters.

For this NSF-WQI method, the ratings of water quality have been defined as indicated in Table 3.

Table 3

Water quality classification based on WQI values (Rajendran & Mansiya 2015)

RangeQuality of waterField of application
91–100 Excellent Can be used for drinking, domestic and industrial purposes 
71–90 Good Can be used for drinking, etc. 
51–70 Medium Can be used only for irrigation and partial body contact 
26–50 Bad Cannot be used for any purpose without treatment 
0–25 Very bad Cannot be used for any purpose without treatment 
RangeQuality of waterField of application
91–100 Excellent Can be used for drinking, domestic and industrial purposes 
71–90 Good Can be used for drinking, etc. 
51–70 Medium Can be used only for irrigation and partial body contact 
26–50 Bad Cannot be used for any purpose without treatment 
0–25 Very bad Cannot be used for any purpose without treatment 

RESULTS AND DISCUSSION

The NSF has given a range of values for WQI to express the quality of water samples (Rajendran & Mansiya 2015). Contamination in groundwater is one of the major issues in water quality studies (Schilling & Wolter 2007; Raju et al. 2009). In this paper, based on the water quality data measured in the dry season of 2015 (June), the NSF-WQI is calculated through seven used water quality variables for understanding the groundwater quality to determine its suitability for drinking, domestic, agricultural and industrial purposes. The quality of water assessed in 10 water samples is shown in Table 4.

Table 4

Overall WQI values of all the samples

ParameterWeighting factor (Q)GW1GW2GW3GW4GW5GW6GW7GW8GW9GW10
DO% saturation 0.17 88 61 84 99 83 92 69 99 87 88 
Fecal coliform 0.16 76 86 67 91 67 76 36 73 91 74 
pH 0.11 92 92 92 90 92 83 93 48 63 85 
Temperature 0.10 27 28 25 23 14 18 17 16 19 21 
T. phosphate 0.10 97 92 93 92 93 93 92 92 92 93 
T. nitrate 0.10 92 95 96 96 96 96 96 96 96 96 
Turbidity 0.08 96 97 97 97 97 97 98 97 97 97 
Total WQI value  81 77 78 86 77 80 68 76 79 79 
ParameterWeighting factor (Q)GW1GW2GW3GW4GW5GW6GW7GW8GW9GW10
DO% saturation 0.17 88 61 84 99 83 92 69 99 87 88 
Fecal coliform 0.16 76 86 67 91 67 76 36 73 91 74 
pH 0.11 92 92 92 90 92 83 93 48 63 85 
Temperature 0.10 27 28 25 23 14 18 17 16 19 21 
T. phosphate 0.10 97 92 93 92 93 93 92 92 92 93 
T. nitrate 0.10 92 95 96 96 96 96 96 96 96 96 
Turbidity 0.08 96 97 97 97 97 97 98 97 97 97 
Total WQI value  81 77 78 86 77 80 68 76 79 79 

The DO value (%saturation) of all the water samples was ranges between 62.4% and 100%. DO is required to convert biodegradable organic matter from one form to another by living organisms, mainly bacteria, to maintain the metabolic process and produce energy for their growth and reproduction (Alam et al. 2012).

The fecal coliforms of the groundwater vary between 2 and 240 colonies/100 ml. The highest value is observed in GW 7 ‘parc au jeu’ (recreational area). These bacteria by themselves are not pathogenic. But if they are accompanied by viruses and parasites, they will cause disease and illness. If the fecal coliform counts are over 200 colonies/100 ml of water samples, there is a great chance that pathogenic organisms are also present (Rajendran & Mansiya 2015). The presence of fecal coliform bacteria at very high levels may indicate potential health risks for human consumption. Fecal coliform bacteria are the most commonly used indicators of fecal pollution in water and food. They inhabit the gastrointestinal tracts of all warm-blooded and some cold-blooded animals, and therefore provide no information about the specific source of fecal contamination. This information is important because (i) fecal material from sources such as humans and cattle can be regarded as ‘high risk’ due to the possible presence of human pathogens and (ii) identification of the fecal source is necessary if management plans for prevention of further contamination are to be developed (Crabill et al. 1999).

The pH values in the samples vary between 7.25 and 9.01 with an average value of 8.13. The pH values for samples are well within the limits prescribed by WHO. It is one of the most important operational water quality parameters (WHO 2011). The term pH is used universally to express the intensity of the acid or alkaline condition of a solution (Alam et al. 2012). No health-based guideline value is proposed for pH, and pH usually has no direct impact on consumers (WHO 2011). Each dissolved metal has its own distinct pH level for maximum hydroxide precipitation. Because metal hydroxides are increasingly soluble above or below their individual maximum precipitation point, even a slight pH adjustment to precipitate one metal may put another back into solution (Mier et al. 2001).

The concentration of nitrate in the study area varies between 1.15 and 2.7 mg/l with an average value of 1.93 mg/l. The nitrate values for all samples are well within the limits set by the WHO standard. Nitrate contamination in groundwater is one of the major issues in water quality studies (Alam et al. 2012). The concentration of nitrogen in groundwater is derived from the biosphere. Nitrate produces no color or odour in water and can cause cancer in humans when consumed over a long period of time (Alam et al. 2012).

The phosphate values of all samples are less than 0.02 mg/l and are well within the limits set by the WHO standard. The significance of phosphorus is principally in regard to the phenomenon of eutrophication, which promotes the growth of algae and other plants leading to blooms, littoral slimes, diurnal DO variations of great magnitude and related problems (EPA 2001).

The temperature values of groundwater samples of the study area vary between 16.60 and 24.80 °C. The temperature is one of the most important characteristics of an aquatic system affecting the DO levels (Rajendran & Mansiya 2015). Cool water is generally more palatable than warm water, and temperature will have an impact on the acceptability of a number of other inorganic constituents and chemical contaminants that may affect taste. High water temperature enhances the growth of microorganisms and may increase problems related to taste, odour, colour and corrosion (WHO 2011).

The turbidity values in water samples vary between 0.43 and 0.73 units. The turbidity values of groundwater samples are well within the limits prescribed by WHO (WHO 1993). The turbidity is an important parameter for characterizing the quality of water (Rajankar et al. 2011). Turbidity in water may be due to a wide variety of suspended materials (Prakash & Somashekar 2006).

The NSF-WQI is classified in five different classes: Very bad; Bad; Medium; Good; Excellent (Table 3). The values of these indices in ten groundwaters of Seraidi municipality are shown in Figure 2.
Figure 2

Water quality grade in the groundwater samples.

Figure 2

Water quality grade in the groundwater samples.

According to the NSF grid, WQI varies between 68 and 86. Calculation of WQI for individual samples is represented in Figure 2. All groundwaters are ranked as good quality and can be used for drinking, domestic and industrial purposes, except the ‘parc au jeu’ groundwater which is classified as medium quality and can be used only for irrigation and partial contact with the body. The presence of fecal coliforms in groundwater makes it inappropriate for human consumption. So the presence of this bacterium may be affected by pollutants from effluents near disposal sites for domestic or agricultural waste (agrochemicals, fertilizers, etc.).

CONCLUSION

As per the NSF, the water quality of groundwater in the study area ranged between medium and good quality. Thus it can be concluded that the groundwater quality of Seraidi is good except for a single groundwater due to the presence of fecal coliform bacteria that may be present from urban effluent discharges. For short-term disinfection of small amounts of water, two options exist. Water can be boiled at a rolling boil for at least 5 to 10 minutes to kill disease-causing bacteria. Alternatively, water can be treated with chlorine to kill bacteria. Keeping in mind increasing urbanization and the pollution caused by urban waste, necessary measures should be taken to reduce the future costs of contamination from entering groundwater. The study establishes that sanitation discharges of contaminants are the main sources of pollution. The study supports water quality monitoring through the use of the WQI for the selected parameters for the quality of places with reference to water.

REFERENCES

REFERENCES
Bharti
N.
Katyal
D.
2011
Water quality indices used for surface water vulnerability assessment
.
International Journal of Environmental Sciences
2
(
1
),
154
.
Brown
R. M.
McClelland
N. I.
Deininger
R. A.
Tozer
R. G.
1970
A water quality index – do we dare?
Water & Sewage Works
117
(
10
),
339
343
.
Collins
C. H.
Lyne
P. M.
1980
Microbial Methods
.
Butterworth and Co., Ltd
,
London
, pp.
125
300
.
Crabill
C.
Donald
R.
Snelling
J.
Foust
R.
Southam
G.
1999
The impact of sediment fecal coliform reservoirs on seasonal water quality in Oak Creek, Arizona
.
Water Research
33
(
9
),
2163
2171
.
Dunnette
D.
1979
A geographically variable water quality index used in Oregon
.
Journal (Water Pollution Control Federation)
51
(
1
),
53
61
.
EPA
2001
Parameters of Water Quality: Interpretation and Standards. Environmental Protection Agency, Ireland
.
Karanth
K.
1987
Ground Water Assessment: Development and Management
.
Tata McGraw-Hill Education, New Delhi, India
.
Khan
F.
Husain
T.
Lumb
A.
2003
Water quality evaluation and trend analysis in selected watersheds of the Atlantic region of Canada
.
Environmental Monitoring and Assessment
88
(
1–3
),
221
248
.
Llamas
M.
Martínez-Santos
P.
2005
Intensive groundwater use: a silent revolution that cannot be ignored
.
Water Science & Technology
51
(
8
),
167
174
.
MacDonald
A.
Bonsor
H.
Dochartaigh
B. É. Ó.
Taylor
R.
2012
Quantitative maps of groundwater resources in Africa
.
Environmental Research Letters
7
(
2
),
024009
.
Mier
M. V.
Callejas
R. L.
Gehr
R.
Cisneros
B. E. J.
Alvarez
P. J.
2001
Heavy metal removal with Mexican clinoptilolite:: multi-component ionic exchange
.
Water Research
35
(
2
),
373
378
.
Prakash
K.
Somashekar
R.
2006
Groundwater quality- assessment on Anekal Taluk, Bangalore Urban district, India
.
Journal of Environmental Biology
27
(
4
),
633
637
.
Rajankar
P. N.
Tambekar
D. H.
Wate
S. R.
2011
Groundwater quality and water quality index at Bhandara District
.
Environmental Monitoring and Assessment
179
(
1–4
),
619
625
.
Rajendran
A.
Mansiya
C.
2015
Physico-chemical analysis of ground water samples of coastal areas of south Chennai in the post-Tsunami scenario
.
Ecotoxicology and Environmental Safety
121
,
218
222
.
Raju
N. J.
Ram
P.
Dey
S.
2009
Groundwater quality in the lower Varuna river basin, Varanasi district, Uttar Pradesh
.
Journal of the Geological Society of India
73
(
2
),
178
192
.
Tyagi
S.
Sharma
B.
Singh
P.
Dobhal
R.
2013
Water quality assessment in terms of water quality index
.
American Journal of Water Resources
1
(
3
),
34
38
.
UNEP
2010
Clearing the Waters: A Focus on Water Quality Solutions. United Nations Environment Programme, Nairobi, Kenya
.
WHO
1993
Guidelines for Drinking-Water Quality. Volume 1: Recommendations. World Health Organization, Geneva, Switzerland
.
WHO
2011
Guidelines for Drinking-water Quality. World Health Organization, Geneva, Switzerland
.
WWAP
2009
Water in a Changing World. The United Nations World Water Development Report 3, UNESCO, Paris, and Earthscan, London
.
WWAP
2012
Managing Water under Uncertainty and Risk
.
The United Nations World Water Development Report 4, UN Water Reports, World Water Assessment Programme
,
UNESCO
,
Paris
.