Abstract

Groundwater is a major water source for drinking, domestic and agricultural activities in the Korkuteli district. However, the intensive agricultural activities in the region negatively affect the groundwater quality. In this study, 30 water samples were collected from springs, wells, and tap waters in dry and wet seasons. Ca-Mg-HCO3 and Mg-Ca-HCO3 were dominant water types in the study area. According to the Gibbs diagrams, which were prepared to determine the mechanism controlling the groundwater geochemistry, samples from both seasons fell in the rock-dominance zone. The water quality index indicates the increase of ion concentrations due to the agricultural effect along with the rainwater in the region. Also, according to WHO standards, water samples are not appropriate to use as drinking water in terms of the heavy metal and fertilizers analysis results. In terms of the irrigation usage, most groundwater samples are suitable in dry and wet seasons. According to HCO3 and SO4 results, the mentioned samples can induce incrustation on metal surfaces and therefore are not recommended for industrial use. Groundwater chemistry in the study area is affected with water–rock interaction and dense agricultural activities. In conclusion, the study area is at high risk in terms of the health risk assessment.

INTRODUCTION

Water is not only the essence of life, but also one of the most important factors determining the quality of human life. The quality of water is extremely important because it is essential for life. The fact that currently 75% of the earth is covered with water gives the idea that there is no water shortage in the world, but the potable water rate is only 0.74% of all waters worldwide (Akın & Akın 2017). In addition, emerging climate changes, developing technology and increasing population are the biggest problems in reaching healthy water today. These problems cause surface waters to gradually decrease and become unusable. A result of this, groundwater is widely used. However, groundwater is not endless and not always suitable for the intended purpose. For this reason, it is very important to determine the amount of groundwater, the quality of the waters and their usage areas. In addition, knowledge of the geochemical evolution of groundwater characteristics is important for the sustainable development and effective management of water resources.

Pollution of groundwater is one of the most significant environmental problems in the world in recent years (Kumar et al. 2014). Groundwater quality depends on the quality of the recharged water, rain and geochemical processes. The quality of groundwater reflects the combined effect of many processes along the groundwater flow path, at any point underground. Geochemical processes are responsible for the seasonal and spatial variation of groundwater chemistry. It is possible to divide the factors affecting these geochemical processes into geogenic and anthropogenic. Geogenic factors are related to geological, hydrological and hydrogeological conditions. Anthropogenic factors that change the chemistry and quality of groundwater are the result of domestic, irrigation and industrial uses. However, at the same time, degradation of the groundwater quality affects its use for drinking, agriculture and industrial activities. Today, approximately 80% of diseases all over the world and one third of deaths in developing countries are caused by polluted drinking water (WHO 2004). Therefore, the determination of the groundwater quality is important for the suitability of the water.

In this study, Korkuteli district in Antalya province, located in the southwest of Turkey, was chosen as a study area. In Korkuteli district, groundwater is the major source of water for human consumption and irrigation. Korkuteli district is an important region of Antalya, especially in terms of greenhousing and other agricultural activities related to livestock. These activities pollute the groundwater anthropogenically. Therefore, groundwater quality in this area is very important in terms of determining the suitability of water for drinking, domestic and agricultural purposes in the study area. In relation to this, the fact that the effect of agricultural activity on the water resources of the region has not been studied in detail before is a major deficiency for the study area. This study aims to resolve this deficiency and the results are important to determine the quality and usability with regard to sustainable management of water resources in the region.

MATERIALS AND METHODS

Study area

Korkuteli district center is located between latitude 37° 3′ 51.9336″ N and longitude 30° 11′ 47.7132″ E coordinates (Figure 1). Korkuteli district center (area 121 km2) was selected as the study area due to the dense agricultural activity and settlement area. The altitude of the district center is 1,020 m. In general, the Mediterranean climate and the terrestrial climate prevail in the district. The mean rainfall for the study area was calculated as 316.39 mm (between 1969 and 2016) by the isohyet method (a line drawn on a map connecting points that receive equal amounts of rainfall) using the data from the meteorological stations in the study area and surrounds. In addition, the mean evapotranspiration was 324.84 mm. The drinking water of the district center is supplied from the springs and well waters in the study area. Also the irrigation waters are supplied from the well and surface flows. Korkuteli and Salamur streams are the most important surface flows in the study area (APESR 2012).

Figure 1

Location and geological maps of the study area.

Figure 1

Location and geological maps of the study area.

Sampling and analysis

A total of 30 water samples from wells, springs and tap waters were analyzed in November 2016 (dry period) and May 2017 (wet period) for the determination of their major and minor chemical characteristics. The water samples were collected in two plastic bottles, pre-washed with 0.5% nitric acid (HNO3) and deionized water from each sampling point. During sampling, two bottles were filled with water from each spot, filtered, and a few drops of HNO3 were added to one water sample that was used to detect major cations, while the second sample was not acidified and was used to detect major anions. All samples were transported and kept in the dark at 4 °C for analysis. The physical parameters, such as hydrogen ion concentration (pH), electrical conductivity (EC), total dissolved solids (TDS), oxidation–reduction potential (Eh) and discharge temperature (°C), were determined in situ using a YSI multi-parameter water quality sonde (YSI 6050).

The major chemical constituents (cations) were analyzed by ICP-MS (inductively coupled plasma-mass spectrometer) at the Bureau Veritas Commodities Canada Ltd (ACME Laboratory Vancouver, Canada, an ISO 9002 accredited company). Bicarbonate (HCO3), carbonate (CO3) concentrations were determined by the titrimetric method; chlorine (Cl), sulphate (SO4), nitrate (NO3), nitrite (NO2) and ammonium (NH4) were determined using ion chromatography in the Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) (Table 1). The charge–balance error in the water samples was less than 5%, which is within the acceptable limits. All mathematical calculations were calculated using Excel 2007 (Microsoft Office). Statistical analysis, such as the correlation matrix, was performed using the SPSS software version 15.

Table 1

Analytical methods used in the study

Type of samples Analysis parameters Method Name of laboratory 
Water samples (Total 30) Discharge temperature (T/C), pH, TDS and electrical conductivity (EC) In situ In situ 
Ag, Al, As, Au, B, Be, Bi, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru,S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb, Zn, Zr ICP mass spectrometry ACME Laboratory (Vancouver, Canada, an ISO 9002 accredited company) 
SO42− Ion chromatography Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) 
Cl Titrimetric Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) 
NO3, NO2, NH4+ Ion chromatography Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) 
HCO3, CO32− Titrimetric Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) 
Type of samples Analysis parameters Method Name of laboratory 
Water samples (Total 30) Discharge temperature (T/C), pH, TDS and electrical conductivity (EC) In situ In situ 
Ag, Al, As, Au, B, Be, Bi, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru,S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb, Zn, Zr ICP mass spectrometry ACME Laboratory (Vancouver, Canada, an ISO 9002 accredited company) 
SO42− Ion chromatography Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) 
Cl Titrimetric Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) 
NO3, NO2, NH4+ Ion chromatography Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) 
HCO3, CO32− Titrimetric Hacettepe University Water Chemistry Laboratory (Ankara, Turkey) 

Methods

Water quality index (WQI)

The relative weight (Wi) is computed from the following equation,  
formula
(1)
where Wi is the relative weight, wi is the weight of each parameter, and n is the number of parameters.
In the next step a quality rating scale (qi) for each parameter is assigned by dividing its concentration in each water sample by its respective standard according to the guidelines laid down in the World Health Organization (WHO 2011) and Turkish Standards Institution (TSI 266 2005), and the result is multiplied by 100 (Equation (2)):  
formula
(2)
where qi is the quality rating, Ci is the concentration of each chemical parameter in each water sample (mg/L), and Si is the drinking water standard for each chemical parameter (mg/L) according to the guidelines of the WHO (2011) and TSI 266 (2005).
For computing WQI, the SI is first determined for each chemical parameter, which is then used to determine the WQI as per the following Equations (3) and (4),  
formula
(3)
 
formula
(4)
where SIi is the sub-index of ith parameter, qi is the rating based on concentration of ith parameter, and n is the number of parameters.

Gibbs ratios

In addition, the Gibbs ratios (Gibbs 1970) were used to determine the mechanism controlling groundwater geochemistry. These ratios were calculated using the following formulas:  
formula
(5)
 
formula
(6)

Health risk assessment

In this study, both the chronic and carcinogenic risk levels were also assessed. Generally, the hazard quotient (HQ noncancer) can be calculated by the following Equation (7) (USEPA 1998),  
formula
(7)
where the NO3, arsenic (As) and chromium (Cr) toxicity reference doses (RfD) are 1.6, 0.0003 and 0.003 mg/kg/day, respectively (USEPA 2005). Non-cancer risk was represented in terms of an HQ noncancer for a single substance separately. If the exposure level of a substance exceeds the corresponding RfD, i.e., HQ noncancer exceeds 1, there may be concern for potential non-carcinogenic effects. The higher the mean value the greater the likelihood of an adverse non-carcinogenic health effect (USEPA 1998; Khan et al. 2008; Muhammad et al. 2010; Varol & Davraz 2016).
The cancer risk (Rcancer) was calculated using Equation (8):  
formula
(8)
where R is the excess probability of developing cancer over a life time as a result of exposure to a contaminant (or carcinogenic risk), ADD is the chronic daily intake (mg/kg/day), and CSF is the slope factor of the contaminant (mg/kg/day) (Equation (8)). According to the US EPA (2005) database the CSF of the contaminant for As is 1.5 mg/kg/day.

RESULT AND DISCUSSION

Geological and hydrogeological setting

The lithological units and interaction time of water with these units control the chemical composition of the groundwater. Firstly the lithological units in the study area have been investigated. All of the lithological units in the study area are autochthonous. These units are Beydağları autochthonous and quaternary alluvium (Qal), slope debris (Qym), old stream terrace fillings (Qt) and old alluvium-slope debris (Q1ym) (Şenel et al. 1989; Şenel 1997; Figure 1, Table 2). Beydağları autochthonous units are composed of Beydağları formation (Kb), Tekkeköy members (Kbt), Çamlıdere olistostrome (Tpç), Küçükköy formation (Tek), Karabayır formation (Tmk), Karakuştepe formation (Tmkt) and Kasaba formation (Tmka) (Şenel et al. 1989; Şenel 1997).

Table 2

Lithostratigraphic relations of the geologic units and hydrogeological properties

Age Formation Lithology Hydrogeological properties 
Quaternary Alluvium (Qal) Gravel sand and mudstone Aqf-1 (Granular aquifer) 
Quaternary Slope debris (Qym) Attached to the loose gravel, sand and mudstone Aqf-1 (Granular aquifer) 
Quaternary Old stream terrace fillings (Qt) Round pebbles, medium-sized conglomerates Aqf-1 (Granular aquifer) 
Quaternary Old alluvium and slope debris, (Q1ym) Attached to small amount of gravel and sand attached Aqf-1 (Granular aquifer) 
Jurassic-Cretaceous Beydağları formation (Kb) Neritic limestones Aqf-2 (Karstic aquifer) 
Jurassic-Cretaceous Tekkeköy member (Kbt) Locally cherty nodular and calcarenite intermediate level, locally abundant globotruncanic micrit Aqj (Aquifuge) 
Lower Paleocene (Danian) Çamlıdere olistostrome (Tpç) Micrit, clayey micrite, claystone, marl, calcarenite, sandstone and similar rocks Aqj (Aquifuge) 
Upper Lutetian-Priabonian Küçükköy formation (Tek) Carbonate intermediate marl, claystone, limestone and clayey limestones Aqj (Aquifuge) 
Akitanian-Lower Burdigalian Karabayır formation (Tmk) Algae limestones Aqf-2 (Karstic aquifer) 
Burdigalian Karakuştepe formation (Tmkt) Sandstone, claystone, siltstone Aqj (Aquifuge) 
Upper Burdigalian-Lower Langiyen Kasaba formation (Tmka) Conglomerates and sandstones Aqt (Aquitard) 
Age Formation Lithology Hydrogeological properties 
Quaternary Alluvium (Qal) Gravel sand and mudstone Aqf-1 (Granular aquifer) 
Quaternary Slope debris (Qym) Attached to the loose gravel, sand and mudstone Aqf-1 (Granular aquifer) 
Quaternary Old stream terrace fillings (Qt) Round pebbles, medium-sized conglomerates Aqf-1 (Granular aquifer) 
Quaternary Old alluvium and slope debris, (Q1ym) Attached to small amount of gravel and sand attached Aqf-1 (Granular aquifer) 
Jurassic-Cretaceous Beydağları formation (Kb) Neritic limestones Aqf-2 (Karstic aquifer) 
Jurassic-Cretaceous Tekkeköy member (Kbt) Locally cherty nodular and calcarenite intermediate level, locally abundant globotruncanic micrit Aqj (Aquifuge) 
Lower Paleocene (Danian) Çamlıdere olistostrome (Tpç) Micrit, clayey micrite, claystone, marl, calcarenite, sandstone and similar rocks Aqj (Aquifuge) 
Upper Lutetian-Priabonian Küçükköy formation (Tek) Carbonate intermediate marl, claystone, limestone and clayey limestones Aqj (Aquifuge) 
Akitanian-Lower Burdigalian Karabayır formation (Tmk) Algae limestones Aqf-2 (Karstic aquifer) 
Burdigalian Karakuştepe formation (Tmkt) Sandstone, claystone, siltstone Aqj (Aquifuge) 
Upper Burdigalian-Lower Langiyen Kasaba formation (Tmka) Conglomerates and sandstones Aqt (Aquitard) 

Secondly, lithological units in the study area were evaluated according to their hydrogeological properties. The general characteristics and hydrogeological properties of the lithological units are given in detail in Table 2. Alluvium and quaternary units represent the most important granular aquifer in the study area (Aqf-1) and have an area of about 45 km2. Limestones can contain significant amounts of groundwater in cracks and melting spaces which allow water to move. For this reason the Beydağları formation, consisting of neritic limestones, and the Karabayır formation, consisting of algae limestones, are defined as ‘karstic aquifer’ (Aqf-2). The Karstic aquifer is the other important aquifer in the study area. The majority of water resources in the study area are discharged from the alluvium and limestones (Figure 1). The Kasaba formation, which consists of conglomerates and sandstones, is classified as ‘aquitard’ (Aqt). Çamlıdere olistostrome, Karakuştepe formation and Küçükköy formation in the study area are classified as ‘aquifuge’ (Aqj) due to their lithological characteristics (Table 2).

Hydrogeochemistry

Groundwater chemistry is controlled by hydrogeochemical processes. There are many chemical processes during the movement of the groundwater from the recharge area to the discharging area. Some of these processes include precipitation, ion exchange, redox condition, leaching and dissolution. The chemical properties of the water determine the usage status for domestic, industrial or agricultural activities. In many developed and developing countries water pollution is one of the most significant factors for the spread of diseases and infant deaths (Kumar et al. 2016). The causes of water pollution can be classified as natural and anthropogenic sources. Accordingly, it is important to know the chemical properties and quality of water for the management and evaluation of groundwater (Kumar et al. 2016). For this reason, in this study we have attempted to determine the physicochemical properties, chemical properties and quality of groundwater in the study area.

Seasonal evaluation of physical parameters

The pH of spring waters (according to the measurement method used for pH, the lower limit of quantitation is ±0.01) varied between 8.71–9.36 and 8.88–9.60 for the dry and wet season, respectively. The pH values of the well waters were measured at 8.54–9.33 in the dry season and 8.89–9.30 in the wet season. Also, the pH of the tap waters varied for the dry and wet season between 8.76–8.93 and 8.85–8.92, respectively. The pH values of all water samples increased in the wet season (Table 3).

Table 3

Physicochemical characteristics of groundwater and tap water in the study area (dry and wet season)

Parameters (mg/l) LOQ* (mg/l) Dry season
 
Wet season
 
Drinking water standards
 
Min. Max. Mean Std. D. Min. Max. Mean Std. D. WHO (2004)  WHO (2011)  TSI 266 (2005)  
EC (μS/cm) 0.0001–0.01 μS/cm 288.800 794.00 561.28 164.15 279.80 809.00 595.79 177.09 1,500 – – 
T (°C) 0.001 °C 11.800 17.60 14.68 1.77 11.80 17.80 15.49 1.58 – – – 
pH ±0.01 8.540 9.36 8.93 0.22 8.85 9.60 9.05 0.22  6.5–8.5 6.5–9.5 
Eh (mV) 0.1 mV 319.50 400.80 372.88 24.05 298.90 388.70 346.77 27.92 – – – 
TDS Variable 187.720 516.100 364.830 106.690 181.87 525.85 387.26 115.11 1,000 – – 
Ca 0.05 59.490 100.170 71.200 11.830 62.55 94.96 73.02 9.09 200 – – 
Mg 0.05 13.040 79.060 45.910 22.370 12.59 79.54 46.03 21.67 150 – – 
Na 0.05 4.630 70.460 25.460 18.740 4.08 74.48 27.93 21.18 200 200 200 
0.05 0.480 2.260 1.170 0.490 0.45 2.18 1.18 0.44 12 – – 
HCO3 ±0.61 225.70 506.30 387.14 101.96 234.63 517.80 398.38 101.74 500 – – 
CO3 ±0.30 less than LOQ less than LOQ – – less than LOQ less than LOQ – – – – – 
Cl ±0.01 2.190 21.340 11.370 6.250 1.990 27.200 12.740 6.790 600 250 250 
SO4 ±0.001 21.070 132.730 59.150 33.400 30.090 155.800 72.470 35.530 250 250 250 
NO2 ±0.001 0.001 0.001 0.001 0.000 0.001 0.001 0.001 0.000 – 0.2 0.5 
NO3 ±0.001 5.570 37.340 19.940 9.700 4.900 52.140 28.810 16.800 45 50 50 
NH4 ±0.001 0.001 0.290 0.060 0.020 0.001 0.130 0.020 0.040 – 1.5 0.5 
Al 0.001 0.001 0.030 0.004 0.0091 0.001 0.050 0.001 0.010 – 0.2 0.5 
As 0.0005 0.080 0.170 0.130 0.020 0.090 0.170 0.130 0.020 – 0.01 0.01 
Cd 0.00005 0.050 0.050 0.050 0.000 0.000 0.000 0.000 0.000 – 0.003 0.005 
Cu 0.0001 0.001 0.040 0.010 0.010 0.000 0.870 0.070 0.220 – 
Cr 0.0005 0.010 0.070 0.030 0.020 0.010 0.080 0.040 0.020 – 0.05 – 
Fe 0.01 0.010 0.110 0.020 0.030 0.010 0.150 0.050 0.030 – – 0.2 
Mn 0.00005 0.00013 0.0039 0.0028 0,0015 0.00022 0.0036 0.020 0.018 – 0.4 0.05 
Ni 0.0002 0.0003 0.0034 0.0030 0.0022 0.0002 0.090 0.010 0.020 – 0.07 0.02 
Pb 0.0001 0.0001 0.002 0.001 0.001 0.0001 0.010 0.0006 0.0003 – 0.01 0.01 
Zn 0.0005 0.0012 0.5306 0.060 0.130 0.0012 2.5351 0.4159 0.76351 – – – 
Valid n = 15             
Parameters (mg/l) LOQ* (mg/l) Dry season
 
Wet season
 
Drinking water standards
 
Min. Max. Mean Std. D. Min. Max. Mean Std. D. WHO (2004)  WHO (2011)  TSI 266 (2005)  
EC (μS/cm) 0.0001–0.01 μS/cm 288.800 794.00 561.28 164.15 279.80 809.00 595.79 177.09 1,500 – – 
T (°C) 0.001 °C 11.800 17.60 14.68 1.77 11.80 17.80 15.49 1.58 – – – 
pH ±0.01 8.540 9.36 8.93 0.22 8.85 9.60 9.05 0.22  6.5–8.5 6.5–9.5 
Eh (mV) 0.1 mV 319.50 400.80 372.88 24.05 298.90 388.70 346.77 27.92 – – – 
TDS Variable 187.720 516.100 364.830 106.690 181.87 525.85 387.26 115.11 1,000 – – 
Ca 0.05 59.490 100.170 71.200 11.830 62.55 94.96 73.02 9.09 200 – – 
Mg 0.05 13.040 79.060 45.910 22.370 12.59 79.54 46.03 21.67 150 – – 
Na 0.05 4.630 70.460 25.460 18.740 4.08 74.48 27.93 21.18 200 200 200 
0.05 0.480 2.260 1.170 0.490 0.45 2.18 1.18 0.44 12 – – 
HCO3 ±0.61 225.70 506.30 387.14 101.96 234.63 517.80 398.38 101.74 500 – – 
CO3 ±0.30 less than LOQ less than LOQ – – less than LOQ less than LOQ – – – – – 
Cl ±0.01 2.190 21.340 11.370 6.250 1.990 27.200 12.740 6.790 600 250 250 
SO4 ±0.001 21.070 132.730 59.150 33.400 30.090 155.800 72.470 35.530 250 250 250 
NO2 ±0.001 0.001 0.001 0.001 0.000 0.001 0.001 0.001 0.000 – 0.2 0.5 
NO3 ±0.001 5.570 37.340 19.940 9.700 4.900 52.140 28.810 16.800 45 50 50 
NH4 ±0.001 0.001 0.290 0.060 0.020 0.001 0.130 0.020 0.040 – 1.5 0.5 
Al 0.001 0.001 0.030 0.004 0.0091 0.001 0.050 0.001 0.010 – 0.2 0.5 
As 0.0005 0.080 0.170 0.130 0.020 0.090 0.170 0.130 0.020 – 0.01 0.01 
Cd 0.00005 0.050 0.050 0.050 0.000 0.000 0.000 0.000 0.000 – 0.003 0.005 
Cu 0.0001 0.001 0.040 0.010 0.010 0.000 0.870 0.070 0.220 – 
Cr 0.0005 0.010 0.070 0.030 0.020 0.010 0.080 0.040 0.020 – 0.05 – 
Fe 0.01 0.010 0.110 0.020 0.030 0.010 0.150 0.050 0.030 – – 0.2 
Mn 0.00005 0.00013 0.0039 0.0028 0,0015 0.00022 0.0036 0.020 0.018 – 0.4 0.05 
Ni 0.0002 0.0003 0.0034 0.0030 0.0022 0.0002 0.090 0.010 0.020 – 0.07 0.02 
Pb 0.0001 0.0001 0.002 0.001 0.001 0.0001 0.010 0.0006 0.0003 – 0.01 0.01 
Zn 0.0005 0.0012 0.5306 0.060 0.130 0.0012 2.5351 0.4159 0.76351 – – – 
Valid n = 15             

*LOQ, the lower limit of quantitation for each parameter.

The EC values, EC, of spring waters (according to the measurement method used for EC, the lower limit of quantitation is 0.0001–0.01 μS/cm.) were measured to be between 288.80–695.00 μS/cm in the dry season and 279.80–708.00 μS/cm in the wet season. The EC values of well waters also varied in the range of 317.10–794.00 μS/cm in the dry season and 309.90–809.00 μS/cm in the wet season. Also, the EC values of tap waters were measured in the range of 474.60–638.00 μS/cm in the dry season and 424.00–744.00 μS/cm in the wet season (Table 3). The high EC values in the wet season indicated the spatial variability of leaching and dilution with recharging rainfall. Also, the higher EC values in the wet season might be attributed to enhanced chemical weathering and lengthier residence time of groundwater in the aquifers (Oinam et al. 2011; Alam et al. 2016).

In addition, the temperature, T (°C), values of spring waters (according to the measurement method used for T (°C), the lower limit of quantitation is 0.001 °C) were measured in the range 12.10–15.50 °C in the dry season and 11.80–15.30 °C in the wet season. The T (°C) values of well waters also varied in the range 11.80–17.60 °C in the dry season and 14.70–17.80 °C in the wet season. Also, the T (°C) values of tap waters were measured in the range 13.10–17.10 °C in the dry season and 15.00–16.60 °C in the wet season (Table 3).

Oxidation–reduction potential, Eh, is a measurement that indicates the degree to which a substance is capable of oxidizing or reducing another substance (APHA 1998). In the present study, Eh values were measured to range from 319.50–400.80 mV in the dry season to 298.90–388.70 mV in the wet season (according to the measurement method used for Eh, the detection limit is 0.1 mV) (Table 3).

Seasonal evaluation of major ions

The most common cations in the groundwater were calcium (Ca) and magnesium (Mg). Subsequently, sodium (Na) and potassium (K) ions were present in the composition of the water in lesser amounts (Tables 3 and 4). The sources of Ca and Mg in water were generally carbonate-rich rocks such as limestone and dolomitic limestone. An increase in Mg ion in the dry and wet seasons was observed at several locations (K1, K4, K5, K7, K11, K12, and K13). The major source of Mg in the groundwater was from interaction of dolomitic limestone with water.

Bicarbonate (HCO3) was the main anionic constituent of the groundwater samples ranging from 225.70 to 506.30 mg/L in the dry season and from 236.65 to 517.80 mg/L in the wet season (Tables 3 and 4). HCO3, representing the major source of alkalinity, generally prevails due to the dissolution of CO2 and carbonates, reaction of silicates with carbonic acid (Ranjan et al. 2013) and oxidation of organic matter (Jeong 2001). Sulphate (SO4) ion, which originates from the oxidation of sulphite, was the most abundant after bicarbonate (Ranjan et al. 2013). Another reason for the excessive amount of sulfate in the groundwater is the presence of anthropogenic inputs. SO4 concentrations in the study area ranged between 21.07 and 132.73 mg/L in the dry season and between 30.09 and 155.80 mg/L in the wet season (Tables 3 and 4). This situation also indicates the entrance of anthropogenic sulphate related to fertilizers in the study area.

Table 4

The major ion sequences of water samples

No. Sample type Dry season (Nov 2016)
 
Wet season (May 2017)
 
Cation sequence Anion sequence Cation sequence Anion sequence 
K1 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K2 Well Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K3 Well Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K4 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K5 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K6 Spring Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K7 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K8 Spring Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K9 Well Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K10 Well Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K11 Tap Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K12 Spring Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K13 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K14 Tap Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K15 Spring Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
No. Sample type Dry season (Nov 2016)
 
Wet season (May 2017)
 
Cation sequence Anion sequence Cation sequence Anion sequence 
K1 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K2 Well Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K3 Well Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K4 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K5 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K6 Spring Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K7 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K8 Spring Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K9 Well Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K10 Well Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K11 Tap Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K12 Spring Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K13 Well Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 Mg > Ca > Na > K HCO3 > SO4 > Cl > CO3 
K14 Tap Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 
K15 Spring Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 Ca > Mg > Na > K HCO3 > SO4 > Cl > CO3 

Seasonal evaluation of fertilizers and heavy metals

In the study, NO2, NO3, NH4 and heavy metal analyses (aluminum (Al), As, cadmium (Cd), copper (Cu), Cr, iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn)) were made to determine pollutant types and sources (Table 3). NO2, NO3, and NH4 are pollutants which come mainly from agricultural and industrial effluents, contain a high concentration of nitrogen and are some of the largest contributors to groundwater pollution in the world (Li et al. 2016). According to the results of analysis, NO2 concentrations were determined as 0.00 mg/L in both periods. The detection limit for nitrite is ±0.001 mg/L. For this reason, the mean and standard deviation values for nitrite were not calculated (Table 3). NO3 concentrations ranged from 2.19 to 21.34 mg/L in the dry season and ranged from 4.90 to 51.00 mg/L in the wet season. In addition, NH4 concentrations were 0 mg/L in the dry season and 0–0.13 mg/L in the wet season (Table 3).

According to the heavy metal analysis results, Al concentrations were determined to be 0 mg/L in the dry season, and 0–0.05 mg/L in the wet season. As concentrations ranged from 0.08 to 0.17 mg/L in the dry season and ranged from 0.09 to 0.17 mg/L in the wet season. Cd concentrations were determined to be 0.05 mg/L in the dry season and 0 mg/L in the wet season. Cu concentration ranged from 0 to 0.04 mg/L in the dry season and from 0 to 0.87 mg/L in the wet season. Besides this, Cr concentrations were determined to be between 0.01 and 0.07 mg/L in the dry season and between 0.01 and 0.08 mg/L in the wet season. Fe concentration ranged from 0.01 to 0.11 mg/L in the dry season and ranged from 0.01 to 0.12 mg/L in the wet season. Mn concentration was determined as 0 mg/L in both seasons. Ni concentrations were determined to be 0 mg/L in the dry season, and between 0–0.09 mg/L in the wet season. Pb concentrations were determined to be 0 mg/L in the dry season, and 0–0.01 mg/L in the wet season. Finally, Zn concentration ranged from 0 to 0.17 mg/L in the dry season and 0 mg/L in the wet season (Table 3). Accordingly, seasonal variation in NO2, NO3, NH4 and heavy metals concentrations is thought to be related to infiltration of rainwater and agricultural activities.

STATISTICAL ANALYSIS

Correlation matrix

Correlation analysis was applied to determine the relationship between physicochemical properties of water samples. It is possible to obtain information about the mineral and chemical processes, and the chemical constituents of water with this relationship were determined by correlation analysis (Varol & Davraz 2015).

In this study, the Kolmogorov–Smirnov (K-S) test was initially used to determine the compatibility of the data to normal distribution (Varol & Şen 2009). According to the K-S test, all the variables were normally distributed with 94% confidence. For this reason, to evaluate the potential relationship between various physiochemical parameters and trace elements, Pearson correlation analysis (PCA) was carried out.

In correlation analysis, if the correlation coefficient is close to 1 or 1, it means a good positive relationship between the two variables. The near zero values are significant if p < 0.05, but there is no relationship between them. Thus, while it is assumed that there is strong correlation between the parameters with r > 0.7, it is said that the r value is moderately correlated between 0.5 and 0.7 (Manish et al. 2006).

All the processes were performed using SPSS software version 15.0 for Windows. In addition, the Pearson correlation matrix was applied separately for the dry and wet seasons in order to study the changes in the relations between the parameters. The correlation matrix of the parameters is given in Table 5 (dry season), and Table 6 (wet season). The analysis results of CO3, NO2, NH4, Cd, Mn, Ni and Pb in the dry season and CO3, NO2, Cd, Mn, Ni in the wet season were 0.00 mg/l, and owing to this results were not evaluated in the correlation matrix.

Table 5

Correlation martix of dry season parameters waters in the study area

    EC pH Eh TDS Ca Mg Na HCO3 Cl SO4 NO3 Al As Cu Cr Fe Zn 
EC                   
                   
−.17                  
.53                   
pH −.72 .20                 
.00 .45                  
Eh .00 .13 −.25                
.99 .62 .35                 
TDS 1.00 −.17 −.72 .00               
.00 .53 .00 .99                
Ca .44 −.38 −.79 .27 .44              
.09 .16 .00 .32 .09               
Mg .97 −.23 −.62 −.12 .97 .30             
.00 .39 .01 .65 .00 .26              
Na .88 −.12 −.40 .07 .88 .17 .87            
.00 .65 .13 .79 .00 .52 .00             
.38 −.21 −.73 −.19 .38 .68 .30 .07           
.16 .44 .00 .49 .16 .00 .27 .79            
HCO3 .97 −.27 −.74 −.10 .97 .50 .96 .81 .47          
.00 .32 .00 .71 .00 .05 .00 .00 .07           
Cl .97 −.24 −.67 −.12 .97 .37 .98 .82 .34 .97         
.00 .37 .00 .65 .00 .17 .00 .00 .21 .00          
SO4 .86 −.17 −.48 .22 .86 .32 .81 .97 .13 .78 .76        
.00 .54 .06 .42 .00 .23 .00 .00 .63 .00 .00         
NO3 .90 −.33 −.81 −.05 .90 .54 .90 .64 .45 .92 .94 .63       
.00 .22 .00 .85 .00 .03 .00 .00 .08 .00 .00 .01        
Al −.00 −.07 −.22 −.19 −.00 .40 −.07 −.20 .52 .09 .03 −.19 .08      
.98 .78 .42 .47 .98 .13 .80 .46 .04 .74 .90 .48 .76       
As −.17 .17 .11 −.06 −.17 −.29 −.16 −.18 −.04 −.14 −.14 −.23 −.20 .27     
.52 .54 .68 .83 .52 .28 .56 .51 .88 .59 .60 .40 .45 .31      
Cu .47 −.10 −.33 .28 .47 .20 .40 .62 .30 .40 .32 .66 .20 −.28 −.28    
.07 .70 .22 .29 .07 .47 .13 .01 .26 .13 .23 .00 .46 .30 .29     
Cr .96 −.22 −.58 .07 .96 .30 .96 .94 .14 .91 .94 .90 .84 −.16 −.19 .47   
.00 .42 .02 .78 .00 .27 .00 .00 .59 .00 .00 .00 .00 .56 .49 .07    
Fe .14 −.06 −.13 −.48 .14 .19 .14 −.05 .42 .28 .22 −.13 .16 .80 .29 −.24 .01  
.60 .82 .63 .07 .60 .48 .59 .86 .11 .30 .41 .62 .56 .00 .28 .37 .95   
Zn .35 .20 −.24 .13 .35 .10 .24 .41 .11 .34 .27 .46 .13 .11 .19 .26 .32 .16 
.19 .47 .38 .63 .19 .71 .37 .12 .68 .21 .31 .08 .62 .68 .49 .33 .23 .55  
    EC pH Eh TDS Ca Mg Na HCO3 Cl SO4 NO3 Al As Cu Cr Fe Zn 
EC                   
                   
−.17                  
.53                   
pH −.72 .20                 
.00 .45                  
Eh .00 .13 −.25                
.99 .62 .35                 
TDS 1.00 −.17 −.72 .00               
.00 .53 .00 .99                
Ca .44 −.38 −.79 .27 .44              
.09 .16 .00 .32 .09               
Mg .97 −.23 −.62 −.12 .97 .30             
.00 .39 .01 .65 .00 .26              
Na .88 −.12 −.40 .07 .88 .17 .87            
.00 .65 .13 .79 .00 .52 .00             
.38 −.21 −.73 −.19 .38 .68 .30 .07           
.16 .44 .00 .49 .16 .00 .27 .79            
HCO3 .97 −.27 −.74 −.10 .97 .50 .96 .81 .47          
.00 .32 .00 .71 .00 .05 .00 .00 .07           
Cl .97 −.24 −.67 −.12 .97 .37 .98 .82 .34 .97         
.00 .37 .00 .65 .00 .17 .00 .00 .21 .00          
SO4 .86 −.17 −.48 .22 .86 .32 .81 .97 .13 .78 .76        
.00 .54 .06 .42 .00 .23 .00 .00 .63 .00 .00         
NO3 .90 −.33 −.81 −.05 .90 .54 .90 .64 .45 .92 .94 .63       
.00 .22 .00 .85 .00 .03 .00 .00 .08 .00 .00 .01        
Al −.00 −.07 −.22 −.19 −.00 .40 −.07 −.20 .52 .09 .03 −.19 .08      
.98 .78 .42 .47 .98 .13 .80 .46 .04 .74 .90 .48 .76       
As −.17 .17 .11 −.06 −.17 −.29 −.16 −.18 −.04 −.14 −.14 −.23 −.20 .27     
.52 .54 .68 .83 .52 .28 .56 .51 .88 .59 .60 .40 .45 .31      
Cu .47 −.10 −.33 .28 .47 .20 .40 .62 .30 .40 .32 .66 .20 −.28 −.28    
.07 .70 .22 .29 .07 .47 .13 .01 .26 .13 .23 .00 .46 .30 .29     
Cr .96 −.22 −.58 .07 .96 .30 .96 .94 .14 .91 .94 .90 .84 −.16 −.19 .47   
.00 .42 .02 .78 .00 .27 .00 .00 .59 .00 .00 .00 .00 .56 .49 .07    
Fe .14 −.06 −.13 −.48 .14 .19 .14 −.05 .42 .28 .22 −.13 .16 .80 .29 −.24 .01  
.60 .82 .63 .07 .60 .48 .59 .86 .11 .30 .41 .62 .56 .00 .28 .37 .95   
Zn .35 .20 −.24 .13 .35 .10 .24 .41 .11 .34 .27 .46 .13 .11 .19 .26 .32 .16 
.19 .47 .38 .63 .19 .71 .37 .12 .68 .21 .31 .08 .62 .68 .49 .33 .23 .55  
Table 6

Correlation martix of wet season parameters waters in the study area

    EC pH Eh TDS Ca Mg Na HCO3 Cl SO4 NO3 NH4 Al As Cu Cr Fe Ni Pb 
EC                     
                     
.46                    
.08                     
pH −.49 −.60                   
.06 .01                    
Eh −.23 −.00 −.17                  
.40 .98 .53                   
TDS 1.00 .46 −.49 −.23                 
.00 .08 .06 .40                  
Ca .45 .18 −.37 .16 .45                
.09 .49 .16 .55 .09                 
Mg .92 .37 −.51 −.37 .92 .29               
.00 .17 .05 .17 .00 .29                
Na .84 .29 −.40 −.24 .84 .32 .85              
.00 .29 .13 .38 .00 .23 .00               
.29 .22 −.37 .23 .29 .63 .17 −.01             
.29 .42 .16 .39 .29 .01 .54 .95              
HCO3 .92 .23 −.39 −.26 .92 .46 .91 .79 .34            
.00 .40 .15 .33 .00 .08 .00 .00 .21             
Cl .86 .34 −.41 −.30 .86 .11 .85 .60 .13 .84           
.00 .20 .12 .26 .00 .68 .00 .01 .63 .00            
SO4 .81 .18 −.28 −.05 .81 .26 .69 .87 .03 .75 .64          
.00 .51 .30 .84 .00 .34 .00 .00 .90 .00 .00           
NO3 .79 .35 −.34 −.46 .79 .34 .80 .51 .38 .86 .82 .43         
.00 .19 .20 .07 .00 .21 .00 .05 .15 .00 .00 .10          
NH4 −.39 −.00 −.12 .31 −.39 −.28 −.42 −.42 .00 −.34 −.15 −.24 −.24        
.14 .98 .65 .25 .14 .30 .11 .11 .97 .20 .57 .38 .38         
Al −.40 −.04 .24 −.32 −.40 −.36 −.35 −.32 −.50 −.42 −.23 −.36 −.22 .46       
.13 .88 .37 .23 .13 .18 .19 .23 .05 .11 .40 .18 .41 .08        
As .23 .26 −.14 .60 .23 .00 .15 .13 .10 .19 .27 .22 .01 .04 −.46      
.39 .34 .60 .01 .39 .97 .57 .62 .71 .49 .32 .43 .94 .87 .08       
Cu .14 .15 −.19 −.48 .14 −.27 .46 .21 −.18 .24 .27 −.16 .36 −.20 .03 .00     
.61 .57 .49 .06 .61 .32 .08 .45 .51 .37 .32 .55 .18 .47 .89 .98      
Cr .95 .41 −.52 −.12 .95 .45 .90 .93 .20 .87 .75 .87 .65 −.42 −.42 .26 .11    
.00 .12 .04 .65 .00 .09 .00 .00 .45 .00 .00 .00 .00 .11 .11 .34 .68     
Fe −.08 .48 .09 −.21 −.08 −.19 −.22 −.09 −.28 −.25 −.05 −.04 −.07 .35 .68 −.10 −.16 −.11   
.76 .06 .74 .43 .76 .48 .42 .73 .30 .35 .84 .86 .77 .19 .00 .70 .54 .68    
Ni .20 −.11 −.12 −.22 .20 −.02 .44 .29 −.15 .30 .28 .01 .13 −.25 −.08 .15 .66 .20 −.36  
.46 .67 .65 .41 .46 .94 .09 .28 .59 .27 .31 .95 .64 .35 .76 .58 .00 .47 .18   
Pb .33 .16 −.21 −.45 .33 .13 .46 .35 −.06 .34 .34 .04 .32 −.33 −.02 −.01 .58 .29 −.02 .78 
.23 .55 .44 .09 .23 .64 .08 .19 .81 .20 .20 .87 .24 .23 .92 .96 .02 .29 .92 .00  
    EC pH Eh TDS Ca Mg Na HCO3 Cl SO4 NO3 NH4 Al As Cu Cr Fe Ni Pb 
EC                     
                     
.46                    
.08                     
pH −.49 −.60                   
.06 .01                    
Eh −.23 −.00 −.17                  
.40 .98 .53                   
TDS 1.00 .46 −.49 −.23                 
.00 .08 .06 .40                  
Ca .45 .18 −.37 .16 .45                
.09 .49 .16 .55 .09                 
Mg .92 .37 −.51 −.37 .92 .29               
.00 .17 .05 .17 .00 .29                
Na .84 .29 −.40 −.24 .84 .32 .85              
.00 .29 .13 .38 .00 .23 .00               
.29 .22 −.37 .23 .29 .63 .17 −.01             
.29 .42 .16 .39 .29 .01 .54 .95              
HCO3 .92 .23 −.39 −.26 .92 .46 .91 .79 .34            
.00 .40 .15 .33 .00 .08 .00 .00 .21             
Cl .86 .34 −.41 −.30 .86 .11 .85 .60 .13 .84           
.00 .20 .12 .26 .00 .68 .00 .01 .63 .00            
SO4 .81 .18 −.28 −.05 .81 .26 .69 .87 .03 .75 .64          
.00 .51 .30 .84 .00 .34 .00 .00 .90 .00 .00           
NO3 .79 .35 −.34 −.46 .79 .34 .80 .51 .38 .86 .82 .43         
.00 .19 .20 .07 .00 .21 .00 .05 .15 .00 .00 .10          
NH4 −.39 −.00 −.12 .31 −.39 −.28 −.42 −.42 .00 −.34 −.15 −.24 −.24        
.14 .98 .65 .25 .14 .30 .11 .11 .97 .20 .57 .38 .38         
Al −.40 −.04 .24 −.32 −.40 −.36 −.35 −.32 −.50 −.42 −.23 −.36 −.22 .46       
.13 .88 .37 .23 .13 .18 .19 .23 .05 .11 .40 .18 .41 .08        
As .23 .26 −.14 .60 .23 .00 .15 .13 .10 .19 .27 .22 .01 .04 −.46      
.39 .34 .60 .01 .39 .97 .57 .62 .71 .49 .32 .43 .94 .87 .08       
Cu .14 .15 −.19 −.48 .14 −.27 .46 .21 −.18 .24 .27 −.16 .36 −.20 .03 .00     
.61 .57 .49 .06 .61 .32 .08 .45 .51 .37 .32 .55 .18 .47 .89 .98      
Cr .95 .41 −.52 −.12 .95 .45 .90 .93 .20 .87 .75 .87 .65 −.42 −.42 .26 .11    
.00 .12 .04 .65 .00 .09 .00 .00 .45 .00 .00 .00 .00 .11 .11 .34 .68     
Fe −.08 .48 .09 −.21 −.08 −.19 −.22 −.09 −.28 −.25 −.05 −.04 −.07 .35 .68 −.10 −.16 −.11   
.76 .06 .74 .43 .76 .48 .42 .73 .30 .35 .84 .86 .77 .19 .00 .70 .54 .68    
Ni .20 −.11 −.12 −.22 .20 −.02 .44 .29 −.15 .30 .28 .01 .13 −.25 −.08 .15 .66 .20 −.36  
.46 .67 .65 .41 .46 .94 .09 .28 .59 .27 .31 .95 .64 .35 .76 .58 .00 .47 .18   
Pb .33 .16 −.21 −.45 .33 .13 .46 .35 −.06 .34 .34 .04 .32 −.33 −.02 −.01 .58 .29 −.02 .78 
.23 .55 .44 .09 .23 .64 .08 .19 .81 .20 .20 .87 .24 .23 .92 .96 .02 .29 .92 .00  

According to the physicochemical PCA results, EC showed positive strong correlation with TDS, Mg, Na, HCO3, Cl, SO4, NO3, and Cr in dry and wet seasons. Also EC showed negative strong correlation with pH in the dry season. T (°C) showed negative moderate correlation with pH in the wet season. pH showed negative strong correlation with TDS, Ca, K, HCO3, NO3 and showed negative moderate correlation with Mg, Cl and Cr ions in the dry season. In the wet season, pH showed negative moderate correlation with only Mg ion. Eh showed positive moderate correlation with As in the wet season only. TDS showed positive strong correlation with Mg, Na, HCO3, Cl, SO4, and NO3, Cr ions in the dry and wet seasons (Tables 5 and 6).

Ca showed positive moderate correlation with K, HCO3 and NO3 in the dry season and also showed positive moderate correlation with K. Mg showed positive strong correlation with Na, HCO3, Cl, SO4, NO3, Cr in the dry season. In the wet season it showed positive strong correlation with Na, HCO3, Cl, NO3 and Cr, and showed positive moderate correlation with SO4 the Na showed positive strong correlation with HCO3, Cl, SO4 and Cr in the dry and wet seasons. It also showed positive moderate correlation with NO3 and Cu in the dry season and showed positive moderate correlation with NO3 and Cl. While K showed a positive moderate correlation with Al in the dry season and negative correlation with Al in the wet season (Tables 5 and 6).

In addition, according to the physicochemical PCA results, HCO3 showed positive strong correlation with Cl, SO4, NO3, Cr in the dry and wet seasons. Cl showed positive strong correlation with SO4, NO3, and Cr in the dry season, and showed positive strong correlation with NO3 and Cr, and positive moderate correlation with SO4 in the wet season. SO4 showed positive strong correlation with Cr in the dry and wet seasons and also showed positive moderate correlation with NO3 and Cr in the dry season (Tables 5 and 6).

According to the PCA results of the heavy metal and pollution parameters, NO3 showed positive moderate correlation with Cr in the dry and wet seasons. While Al showed positive moderate correlation with Fe in the dry season, it showed positive strong correlation with Fe in the wet season. Cu showed positive moderate correlation with Ni and Pb ions. Ni showed positive moderate correlation with Pb ion (Tables 5 and 6). Statistical analysis results indicated that water resources were affected from rock-water interaction, climatic conditions, ion exchange processes and excess application of fertilizer in the study area.

Hydrogeochemical facies

Hydrogeochemical facies are a useful tool for determining the chemical history and origins of groundwater. They are used to show similarities and differences in the chemistry of groundwater samples based on dominant cations and anions (Piper 1944, 1953). The hydrogeochemical evolution of groundwater in the study area was prepared separately for both dry and rainy periods and was evaluated using a Piper diagram using the concentrations of major cations (Ca, Mg, Na and K) and anions (HCO3, SO4, and Cl) in meq/l.

According to the Piper diagrams, in the study area Ca-Mg-HCO3 and Mg-Ca-HCO3 as the dominant water types were observed in both the dry and wet seasons (Figure 2). Ca-Mg-HCO3 and Mg-Ca-HCO3 facies represented 53.33% and 46.66% of the total water samples, respectively (Table 4; Figure 2). These water types originated from the dissolution of limestone and dolomitic limestone in the aquifer material.

Figure 2

Piper diagrams in dry and wet season (Piper 1944).

Figure 2

Piper diagrams in dry and wet season (Piper 1944).

Mechanism controlling the groundwater geochemistry

Some diagrams have been proposed by Gibbs (1970) to determine groundwater chemistry, rock–water interaction in aquifers, and sedimentation mechanism in groundwater. There are two types of diagrams. The parameters used in these diagrams are dominant anions (Gibbs Ratio I) and cations (Gibbs Ratio II) and TDS values. These diagrams are extensively used to determine the chemical composition of the water in relation to processes such as precipitation, rock and evaporation dominance.

In this study, Gibbs Ratio I values varied from 0.01 to 0.04 with an average value of 0.02, and Gibbs Ratio II values varied from 0.08 to 0.52 with an average value of 0.24 in the dry season. Gibbs Ratio I values varied from 0.01 to 0.05 with an average value of 0.02, and Gibbs Ratio II values varied from 0.06 to 0.53 with an average value of 0.25 in the wet season. According to the Gibbs diagrams, water samples from dry and wet seasons fall in the rock dominance zone (Figure 3). The diagram indicates that chemical weathering of the rock-forming minerals is the main process through which ions are contributed to the groundwater.

Figure 3

Gibbs diagrams (Gibbs 1970) illustrating the mechanisms controlling the chemistry of groundwater samples.

Figure 3

Gibbs diagrams (Gibbs 1970) illustrating the mechanisms controlling the chemistry of groundwater samples.

EVALUATION OF WATER QUALITY

In this section of the study, the water quality assessments were carried out to identify its suitability for drinking, irrigation, and industrial purposes.

Evaluation of water quality as drinking water

Water quality index (WQI) evaluations

Water quality index (WQI) is defined as a method to determine the influence of each water quality parameter on the overall quality of water for human consumption (Varol & Davraz 2015). WQI is an important parameter for determining groundwater quality and its suitability for drinking water. The WQI index is a measure of the composition of water in light of certain defined objectives. In general, the purpose of the index is to compare each of the main parameters of drinking water with the World Health Organization (WHO) and national standards (Yidana et al. 2010). In this study, WQI was computed in three steps. The analysis results were evaluated and compared with WHO (2011) and TSI 266 (2005) (Table 7).

Table 7

Relative weight of physicochemical parameters in study area

Chemical parameters WHO (2011) standards Turkısh Drinking Water Standard (TS 266) (2005) Weight (wi) Relative weight (Wi) 
Total dissolved solids (TDS) 500–1,500 1,500 0.04 
pH 6.5–8.5 6.5–9.5 0.05 
HCO3 (mg/l) – – 0.01 
Cl (mg/l) 250 250 0.05 
SO4 (mg/l) 250 250 0.05 
NO3 (mg/l) 50 50 0.05 
NO2 (mg/l) 3.0 0.50 0.05 
NH4 (mg/l) 0.05 
Ca (mg/l) 300 200 0.03 
Mg (mg/l) 30 150 0.03 
Na (mg/l) 200 200 0.04 
K (mg/l) – 12 0.02 
As (mg/l) 0.01 0.01 0.05 
Cr (mg/l) 0.05 – 0.05 
   ∑wi = 57 ∑wi = 1 
Chemical parameters WHO (2011) standards Turkısh Drinking Water Standard (TS 266) (2005) Weight (wi) Relative weight (Wi) 
Total dissolved solids (TDS) 500–1,500 1,500 0.04 
pH 6.5–8.5 6.5–9.5 0.05 
HCO3 (mg/l) – – 0.01 
Cl (mg/l) 250 250 0.05 
SO4 (mg/l) 250 250 0.05 
NO3 (mg/l) 50 50 0.05 
NO2 (mg/l) 3.0 0.50 0.05 
NH4 (mg/l) 0.05 
Ca (mg/l) 300 200 0.03 
Mg (mg/l) 30 150 0.03 
Na (mg/l) 200 200 0.04 
K (mg/l) – 12 0.02 
As (mg/l) 0.01 0.01 0.05 
Cr (mg/l) 0.05 – 0.05 
   ∑wi = 57 ∑wi = 1 

Each of the 21 parameters (pH, TDS, Ca, Mg, Na, K, HCO3, Cl, SO4, NO2, NO3, NH4, As, Cr,) has been assigned a weight (wi) according to its relative importance for drinking water quality (Table 7). Greater weight is assigned to parameters which have critical health effects and whose presence above certain critical concentration limits could limit the usability of the resource for domestic purposes (Yidana et al. 2010). Therefore in this study, the maximum weight of 5 has been assigned to parameters including TDS, Cl, SO4, NO3, NO2, NH4, As and Cr due to their major importance for water quality assessment (Srinivasamoorthy et al. 2008). The minimum weight (1) has been assigned to the parameter HCO3 due to its having the least importance for water quality assessment. Other parameters, including pH, Ca, Mg, Na, and K, were assigned to weights between 1 and 5 depending on their importance in water quality determination.

Finally, the WQI values obtained from the calculations were evaluated together with the water quality types in Table 8. In addition, the WQI values for each sample and their types are shown in Table 9. According to Table 9, the calculated WQI values ranged from 113.15 to 177.67 and from 103.84 to 204.00 for dry season and wet seasons, respectively. In addition, during the dry season, 100% of groundwater samples represent ‘Poor water’; during the wet season 93.33% of groundwater samples represent ‘Poor water’ and 6.66% indicate ‘Very Poor water’. This indicates that the quality of wet season samples is very low. So, the increase of ion concentrations is related to infiltration of rainwater in the farmland.

Table 8

WQI water types (Sahu & Sikdar 2008)

Range Type of water 
<50 Excellent water 
50–100.1 Good water 
100–200.1 Poor water 
200–300.1 Very poor water 
>300 Water unsuitable for drinking purposes 
Range Type of water 
<50 Excellent water 
50–100.1 Good water 
100–200.1 Poor water 
200–300.1 Very poor water 
>300 Water unsuitable for drinking purposes 
Table 9

The WQI values and their types for each sample in dry and wet season in the study area

Sample no. Dry season
 
Wet season
 
∑ SI Type of water ∑ SI Type of water 
K1 113.15 Poor water 142.85 Poor water 
K2 148.08 Poor water 128.61 Poor water 
K3 114.26 Poor water 103.84 Poor water 
K4 148.44 Poor water 156.38 Poor water 
K5 162.80 Poor water 164.45 Poor water 
K6 151.53 Poor water 106.70 Poor water 
K7 169.72 Poor water 166.60 Poor water 
K8 143.00 Poor water 181.55 Poor water 
K9 175.45 Poor water 166.55 Poor water 
K10 141.40 Poor water 140.34 Poor water 
K11 173.25 Poor water 185.40 Poor water 
K12 157.84 Poor water 177.81 Poor water 
K13 177.67 Poor water 204.00 Very Poor water 
K14 122.58 Poor water 143.11 Poor water 
K15 154.88 Poor water 163.86 Poor water 
Sample no. Dry season
 
Wet season
 
∑ SI Type of water ∑ SI Type of water 
K1 113.15 Poor water 142.85 Poor water 
K2 148.08 Poor water 128.61 Poor water 
K3 114.26 Poor water 103.84 Poor water 
K4 148.44 Poor water 156.38 Poor water 
K5 162.80 Poor water 164.45 Poor water 
K6 151.53 Poor water 106.70 Poor water 
K7 169.72 Poor water 166.60 Poor water 
K8 143.00 Poor water 181.55 Poor water 
K9 175.45 Poor water 166.55 Poor water 
K10 141.40 Poor water 140.34 Poor water 
K11 173.25 Poor water 185.40 Poor water 
K12 157.84 Poor water 177.81 Poor water 
K13 177.67 Poor water 204.00 Very Poor water 
K14 122.58 Poor water 143.11 Poor water 
K15 154.88 Poor water 163.86 Poor water 

Potability of water in terms of fertilizers and heavy metal concentrations

In many parts of the world, groundwater is exposed to pollution from fertilizers and pesticides due to human activities, mostly involving intensive agriculture and urbanization. Fertilizer usage varies according to soil structure, climate and plant species and nowadays, the most widely used fertilizers are nitrogen and its derivatives urea, phosphate and potassium fertilizers. One of the most common ways in which nitrogen and its derivatives pass into groundwater is leaching from agricultural lands. Accordingly, the nitrate level in the groundwater is greatly affected by fertilizer quantity and types (Rahmati et al. 2015). Chemical or artificial fertilizers contain heavy metals and metalloids at lower amounts compared with nitrogen and its derivatives. The continuous application of these fertilizers over the last fifty years may have contributed to increasing heavy metals and metalloids in soil and groundwater (Jayasumana et al. 2015).

In addition, chemicals associated with the use of excessive fertilizers and pesticides may cause negative effects on human health. Notably, excess nitrate in the drinking water can cause health risks such as methemoglobin, which depletes blood oxygen levels in infants, causes gastric problems in adults, decreased functioning of the thyroid gland, and cancer due to formation of nitrosamines, as well as multiple sclerosis (Zhaia et al. 2017). Other agrochemicals, such as arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and lead (Pb), have toxic properties and pollute groundwater. Phosphorus-containing artificial fertilizers are the main source of agricultural As pollution in groundwater (Sönmez et al. 2008). Triple Super Phosphate (TSP) type phosphate fertilizers are one of the main sources of As. The amount of As in the TSP is 15 times greater than the insecticide Dimethoate, which has contained the highest level of As among insecticides. Arsenic in soil can contaminate drinking water and food crops including vegetables, fruits and field crops (Jayasumana et al. 2015). Groundwaters containing As considerably affect human health and cause fatal consequences due to their carcinogenic effects. Epidemiologic studies have shown that As exposure is related to skin, liver, bladder, and other cancers (Lin et al. 2016).

The study area is an important region of intensive agricultural activity, particularly when it comes to greenhousing (Figure 4; ADPFAL 2011; APESR 2012). Agricultural products and cultivated areas in the region are given in Table 10 (ADPFAL 2016). The use of artificial fertilizers is very high in the study area. The fertilizer types and consumption quantities in the study area are given in Table 11 (ADPFAL 2016). According to Table 11, nitrogen and its derivatives urea, phosphate and potassium are the main groups of chemical fertilizers used in Korkuteli district.

Figure 4

Land use map of the study area (ADPFAL 2011; APESR 2012).

Figure 4

Land use map of the study area (ADPFAL 2011; APESR 2012).

Table 10

Agricultural products and cultivated field quantities in the Korkuteli district (ADPFAL 2016)

Veg. Dec.* Fruit Dec. Field crops Dec. Forage crops Dec. Cereal Dec. Legumes Dec. 
Cauliflower 400 Apple 21.050 Anise 6.500 Vetches 13.500 Barley 243.248 Chickpea 120.000 
Mushroom 21.000 ton Pear 39.810 Potato 4.125 Clover 5.500 Wheat 238.187 Beans 3.150 
Tomato 6.400 Apricot 15.000 Sugar beet 2.943 Corn 3.000 Oat 3.373 Lentil 
Beans 3.750 Peach 14.000 Sunflower 1.665 Sainfoin 1.200 Safflower 950 Total 123.155 
Watermelon 3.200 Cherry 12.000 Fennel 1.500 Triticale 1.050 Rye 800 
Cantalpe 3.000 Plum 7.500 Loveinamist 250 Pea 75 Tritikale 504 
Cucumber 2.950 Sour cherry 7.500 Lavender Forage Turnip 30 Total 487.062 
Pepper 1.655 Walnut 6.000 Balm Sorghum 10 
Lettuce 1.100 Grape 5.130 Dead nettle Mangel 
Cabbage 900 Olive 1.200 Coriander Total 24.370 
Onion 800 Almond 1.200 Thyme 
Garlic 800 Strawberry 150 Sage 
Kidney bean 800 Quince 90 Total 17.013 
Pumpkin 410 Pomegranate 65 
Spinach 400 Antep Peanuts 20 
Leek 400 Oleaster 
Eggplant 245 Cranberry 
Celery 80 Mulberry 
Okra 80 Total 130.734 
Broccoli 25 
Radish 12 
Enginar 10 
Cress 
Mint 
Total 27.427 
Overall Total 809.771 
Veg. Dec.* Fruit Dec. Field crops Dec. Forage crops Dec. Cereal Dec. Legumes Dec. 
Cauliflower 400 Apple 21.050 Anise 6.500 Vetches 13.500 Barley 243.248 Chickpea 120.000 
Mushroom 21.000 ton Pear 39.810 Potato 4.125 Clover 5.500 Wheat 238.187 Beans 3.150 
Tomato 6.400 Apricot 15.000 Sugar beet 2.943 Corn 3.000 Oat 3.373 Lentil 
Beans 3.750 Peach 14.000 Sunflower 1.665 Sainfoin 1.200 Safflower 950 Total 123.155 
Watermelon 3.200 Cherry 12.000 Fennel 1.500 Triticale 1.050 Rye 800 
Cantalpe 3.000 Plum 7.500 Loveinamist 250 Pea 75 Tritikale 504 
Cucumber 2.950 Sour cherry 7.500 Lavender Forage Turnip 30 Total 487.062 
Pepper 1.655 Walnut 6.000 Balm Sorghum 10 
Lettuce 1.100 Grape 5.130 Dead nettle Mangel 
Cabbage 900 Olive 1.200 Coriander Total 24.370 
Onion 800 Almond 1.200 Thyme 
Garlic 800 Strawberry 150 Sage 
Kidney bean 800 Quince 90 Total 17.013 
Pumpkin 410 Pomegranate 65 
Spinach 400 Antep Peanuts 20 
Leek 400 Oleaster 
Eggplant 245 Cranberry 
Celery 80 Mulberry 
Okra 80 Total 130.734 
Broccoli 25 
Radish 12 
Enginar 10 
Cress 
Mint 
Total 27.427 
Overall Total 809.771 

*Dec. = decare (1,000 m2).

Table 11

The types of fertilizers used and consumption quantities in the Korkuteli district (ADPFAL 2016)

Type of fertilizer Composition of the fertilizer Tonne 
AMMONIUM SULFATE 21% 21% Ammonium Nitrogen (NH4-N). 24% Sulphur (S) 1,168 
AMMONIUM NİTRATE 26% 33% Nitrogen (N). 16% Ammonium Nitrogen (NH4-N). 16%Nitrate Nitrogen (NO3-N) 817 
AMMONIUM NİTRATE 33% 33% Total Nitrogen (N). 16.5% Ammonium Nitrogen (NH4-N). 16.5%Nitrate Nitrogen (NO3-N) 1,785 
UREA 46% 46% Urea Nitrogen (NH2-N) 957 
TRIPLE SUPER PHOSPHATE 43–44% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble 29 
DAP (Diammonium Phosphate) 18-46-0 18% Nitrogen (N). 18% Ammonium Nitrogen (NH4-N). 46% Phosphorus (P2O5817 
20-20-0 COMPOUND 20% Nitrogen (N). 20% Ammonium Nitrogen (NH4-N). 20% Phosphorus (P2O55,189 
20-20-0 + Zn 20% Nitrogen (N). 17% Ammonium Nitrogen (NH4-N). 3% Urea Nitrogen (NH2-N). 20% Phosphorus (P2O5). 1% Zinc (Zn) 198 
15-15-15 COMPOUND 15% Total Nitrogen (N). 13% Ammonium Nitrogen (NH4-N). 5% Urea Nitrogen (NH2-N). 13% Phosphorus Pentaoxide Soluble in Water (P2O5). 15% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 15% Potassium Oxide Soluble in Water (K2O) 645 
15-15-15 + Zn COMPOUND 15% Nitrogen (N). 15% Phosphorus Pentaoxide Soluble in Water (P2O5). 15% Potassium Oxide Soluble in Water (K2O). 9% Sulphur (S). 1% Zinc (Zn) 822 
MAP (Mono Ammonium Phosphate) 12% Total Nitrogen (N). 12% Ammonium Nitrogen (NH4-N). 61% Phosphorus Pentaoxide Soluble in Water (P2O5). 27 
POTASSIUM NITRATE 13% Total Nitrogen (N). 13%Nitrate Nitrogen (NO3-N). 45.5% Potassium Oxide Soluble in Water (K2O) 46 
POTASSIUM SULPHATE 50% Potassium Oxide Soluble in Water (K2O). 46% Sulphur Trioxide (SO3) Soluble in Water 50 
CALCIUM NITRATE 15.5% Total Nitrogen (N). 14.5% Nitrate Nitrogen (NO3-N). 1.1% Ammonium Nitrogen (NH4-N). 25.6% Calcium Oxide (CaO) Soluble in Water 101 
COMPOUND (25-05-10) 25% Total Nitrogen (N). 21% Ammonium Nitrogen (NH4-N). 5% Phosphorus Pentaoxide Soluble in Water (P2O5). 10% Potassium Oxide Soluble in Water (K2O) 414 
COMPOUND (13-24-13) 13% Total Nitrogen (N). 9.1% Ammonium Nitrogen (NH4-N). 3.9% Urea Nitrogen (NH2-N). 24% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 12% Potassium Oxide Soluble in Water (K2O). 10% Total Sulphur Trioxide (SO3) Soluble in Water. 1% Total Iron. 1% 0.5% Iron Soluble in Water. 1% Total Zinc (Zn) 166 
COMPOUND (12-30-12) 12% Total Nitrogen (N). 9% Ammonium Nitrogen (NH4-N). 3% Urea Nitrogen (NH2-N). 28% Phosphorus Pentaoxide Soluble in Water (P2O5). 30% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 12% Potassium Oxide Soluble in Water (K2O) 
COMPOUND (16-16-16) 16% Total Nitrogen (N). 4% Ammonium Nitrogen (NH4-N). 2% Nitrate Nitrogen (NO3-N). 10% Urea Nitrogen (NH2-N). 16% Phosphorus Pentaoxide Soluble in Water (P2O5). 16% Potassium Oxide Soluble in Water (K2O) 56 
COMPOUND (10-25-20) 10% Total Nitrogen (N). 7% Ammonium Nitrogen (NH4-N). 3% Urea Nitrogen (NH2-N). 15% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 13% Phosphorus Pentaoxide Soluble in Water (P2O5). 25% Potassium Oxide Soluble in Water (K2O). 20% Total Sulphur Trioxide (SO3) Soluble in Water. 1% Zinc (Zn) 28 
COMPOUND (20-32-0) 20% Total Nitrogen (N). 16% Ammonium Nitrogen (NH4-N). 4% Urea Nitrogen (NH2-N). 32% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 30% Phosphorus Pentaoxide Soluble in Water (P2O5). 15% Total Sulphur Trioxide (SO3) Soluble in Water. 1% Zinc (Zn) 637 
COMPOUND (10-20-20) 10% Total Nitrogen (N). 20% Phosphorus Pentaoxide Soluble in Water (P2O5). 20% Potassium Oxide Soluble in Water (K2O). 6% Sulphur (S). 1% Zinc (Zn) 32 
TOTAL (TONNE)  13,984 
Type of fertilizer Composition of the fertilizer Tonne 
AMMONIUM SULFATE 21% 21% Ammonium Nitrogen (NH4-N). 24% Sulphur (S) 1,168 
AMMONIUM NİTRATE 26% 33% Nitrogen (N). 16% Ammonium Nitrogen (NH4-N). 16%Nitrate Nitrogen (NO3-N) 817 
AMMONIUM NİTRATE 33% 33% Total Nitrogen (N). 16.5% Ammonium Nitrogen (NH4-N). 16.5%Nitrate Nitrogen (NO3-N) 1,785 
UREA 46% 46% Urea Nitrogen (NH2-N) 957 
TRIPLE SUPER PHOSPHATE 43–44% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble 29 
DAP (Diammonium Phosphate) 18-46-0 18% Nitrogen (N). 18% Ammonium Nitrogen (NH4-N). 46% Phosphorus (P2O5817 
20-20-0 COMPOUND 20% Nitrogen (N). 20% Ammonium Nitrogen (NH4-N). 20% Phosphorus (P2O55,189 
20-20-0 + Zn 20% Nitrogen (N). 17% Ammonium Nitrogen (NH4-N). 3% Urea Nitrogen (NH2-N). 20% Phosphorus (P2O5). 1% Zinc (Zn) 198 
15-15-15 COMPOUND 15% Total Nitrogen (N). 13% Ammonium Nitrogen (NH4-N). 5% Urea Nitrogen (NH2-N). 13% Phosphorus Pentaoxide Soluble in Water (P2O5). 15% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 15% Potassium Oxide Soluble in Water (K2O) 645 
15-15-15 + Zn COMPOUND 15% Nitrogen (N). 15% Phosphorus Pentaoxide Soluble in Water (P2O5). 15% Potassium Oxide Soluble in Water (K2O). 9% Sulphur (S). 1% Zinc (Zn) 822 
MAP (Mono Ammonium Phosphate) 12% Total Nitrogen (N). 12% Ammonium Nitrogen (NH4-N). 61% Phosphorus Pentaoxide Soluble in Water (P2O5). 27 
POTASSIUM NITRATE 13% Total Nitrogen (N). 13%Nitrate Nitrogen (NO3-N). 45.5% Potassium Oxide Soluble in Water (K2O) 46 
POTASSIUM SULPHATE 50% Potassium Oxide Soluble in Water (K2O). 46% Sulphur Trioxide (SO3) Soluble in Water 50 
CALCIUM NITRATE 15.5% Total Nitrogen (N). 14.5% Nitrate Nitrogen (NO3-N). 1.1% Ammonium Nitrogen (NH4-N). 25.6% Calcium Oxide (CaO) Soluble in Water 101 
COMPOUND (25-05-10) 25% Total Nitrogen (N). 21% Ammonium Nitrogen (NH4-N). 5% Phosphorus Pentaoxide Soluble in Water (P2O5). 10% Potassium Oxide Soluble in Water (K2O) 414 
COMPOUND (13-24-13) 13% Total Nitrogen (N). 9.1% Ammonium Nitrogen (NH4-N). 3.9% Urea Nitrogen (NH2-N). 24% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 12% Potassium Oxide Soluble in Water (K2O). 10% Total Sulphur Trioxide (SO3) Soluble in Water. 1% Total Iron. 1% 0.5% Iron Soluble in Water. 1% Total Zinc (Zn) 166 
COMPOUND (12-30-12) 12% Total Nitrogen (N). 9% Ammonium Nitrogen (NH4-N). 3% Urea Nitrogen (NH2-N). 28% Phosphorus Pentaoxide Soluble in Water (P2O5). 30% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 12% Potassium Oxide Soluble in Water (K2O) 
COMPOUND (16-16-16) 16% Total Nitrogen (N). 4% Ammonium Nitrogen (NH4-N). 2% Nitrate Nitrogen (NO3-N). 10% Urea Nitrogen (NH2-N). 16% Phosphorus Pentaoxide Soluble in Water (P2O5). 16% Potassium Oxide Soluble in Water (K2O) 56 
COMPOUND (10-25-20) 10% Total Nitrogen (N). 7% Ammonium Nitrogen (NH4-N). 3% Urea Nitrogen (NH2-N). 15% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 13% Phosphorus Pentaoxide Soluble in Water (P2O5). 25% Potassium Oxide Soluble in Water (K2O). 20% Total Sulphur Trioxide (SO3) Soluble in Water. 1% Zinc (Zn) 28 
COMPOUND (20-32-0) 20% Total Nitrogen (N). 16% Ammonium Nitrogen (NH4-N). 4% Urea Nitrogen (NH2-N). 32% Phosphorus Pentoxide (P2O5) in neutral ammonium citrate soluble. 30% Phosphorus Pentaoxide Soluble in Water (P2O5). 15% Total Sulphur Trioxide (SO3) Soluble in Water. 1% Zinc (Zn) 637 
COMPOUND (10-20-20) 10% Total Nitrogen (N). 20% Phosphorus Pentaoxide Soluble in Water (P2O5). 20% Potassium Oxide Soluble in Water (K2O). 6% Sulphur (S). 1% Zinc (Zn) 32 
TOTAL (TONNE)  13,984 

WHO has specified the maximum safe nitrite, nitrate and ammonium concentration in drinking water to be 0.2, 50 and 1.5 mg/L, respectively (WHO 2011). Nitrate concentrations exceeding the 50 mg/l limit value in drinking water can endanger human health, especially in infants (Vidyalakshmi et al. 2013). According to the analysis results, nitrate concentrations in the study area exceed the limit value only in the wet season (K2, K5 and K7). In addition, a nitrate level of 3 mg/L or greater indicates contamination. Water with a nitrate concentration of greater than 10 mg/L should not be used to prepare infant formula or other foods or be given to a child younger than 1 year to drink (Greer & Shannon 2005; PWP 2009). As water in the study area is used by people of all ages living in the region, this underlines the importance of this study. The analysis results showed that all waters in the study area both in dry and wet seasons were contaminated and these waters are not suitable for drinking owing to their nitrate concentrations (Table 3).

In addition, arsenic concentrations in all samples exceeded the threshold value determined by WHO (2011) in both periods. Cr concentrations exceeded the limit values at K1, K4 and K5 samples in the dry season and exceeded the limit values at K1, K2, K4, K5, K7, K11 and K12 samples in the wet season. In addition, Ni (K7 and K12) and Pb acceptable concentrations (K1, K7 and K12) were determined to be exceeded only during the wet season. Accordingly, it is not appropriate to use as drinking water according to the heavy metal analysis results (Table 3).

Evaluation of water quality as irrigation use

The sodium adsorption ratio (SAR), permeability index (PI), sodium percentage (Na %), magnesium hazard (MH), and residual sodium carbonate (RSC) indices were used to determine the suitability of groundwater for agricultural irrigation and the results are indicated in Table 12.

Table 12

Irrigational quality parameters results in groundwater samples in the study area

Parameters Range Groundwater class (irrigation uses) Samples (n = 15) in dry season
 
Samples (n = 15) in wet season
 
In (no.) In (%) In (no.) In (%) 
SAR (Bouwer 1978<6 No problem 13 86.67 15 100 
6–9 Increasing problem 13.33 – – 
>9 Severe problem – – – – 
Permeability index (PI) (Doneen 1964<60 Suitable 15 100 15 100 
>60 Unsuitable – – – – 
Na % (Wilcox 1955<20 Excellent 13 86.67 13 86.67 
20–40 Good 13.33 13.33 
40–60 Permissible – – – – 
60–80 Doubtful – – – – 
>80 Unsuitable – – – – 
Magnesium hazard (Paliwal 1972<50 Suitable 53.33 53.33 
>50 Unsuitable 46.66 46.66 
Residual sodium carbonate (Lloyd & Heathcote 1985<1.25 Suitable 15 100 15 100 
1.25–2.50 Marginal – – – – 
>2.50 Unsuitable – – – – 
Parameters Range Groundwater class (irrigation uses) Samples (n = 15) in dry season
 
Samples (n = 15) in wet season
 
In (no.) In (%) In (no.) In (%) 
SAR (Bouwer 1978<6 No problem 13 86.67 15 100 
6–9 Increasing problem 13.33 – – 
>9 Severe problem – – – – 
Permeability index (PI) (Doneen 1964<60 Suitable 15 100 15 100 
>60 Unsuitable – – – – 
Na % (Wilcox 1955<20 Excellent 13 86.67 13 86.67 
20–40 Good 13.33 13.33 
40–60 Permissible – – – – 
60–80 Doubtful – – – – 
>80 Unsuitable – – – – 
Magnesium hazard (Paliwal 1972<50 Suitable 53.33 53.33 
>50 Unsuitable 46.66 46.66 
Residual sodium carbonate (Lloyd & Heathcote 1985<1.25 Suitable 15 100 15 100 
1.25–2.50 Marginal – – – – 
>2.50 Unsuitable – – – – 

Sodium adsorption ratio

The calculated values of SAR ranged from 0.76 to 8.24, and 86.67% of the samples were considered ‘no problem’ for irrigation, but 13.33% of samples were considered as an ‘increasing problem’ for irrigation in the dry season. Apart from this, all samples fall into the ‘no problem’ category in the wet season (Table 12).

In addition, the relationship between SAR and EC values was prepared using a US salinity diagram for both seasons and the suitability of the waters for irrigation was evaluated. According to the diagram, 86.67% of the samples fall in the field of C2–S1, indicating medium salinity and low alkalinity content. These waters can be suitable for irrigation. 6.66% of the samples fall in the field of C2–S2 indicating medium salinity and medium alkalinity content, and 6.66% of the samples fall in the field of C3–S2 category in the dry season, indicating high salinity and medium alkalinity content (Figure 5). The use of waters in C2–S2 and C3–S2 categories is limited to irrigation water. In the wet season, 73.33% of the samples fall in the category of C2–S1 and 26.66% of the samples fall in the C3–S1 category, indicating that these water samples are found to have high salinity and low sodium content, which can be used for irrigation in all soil types with low risk of sodium in the wet season (Figure 5).

Figure 5

Salinity (EC) and sodium hazard (SAR) of irrigation water in US salinity diagram (dry and wet season).

Figure 5

Salinity (EC) and sodium hazard (SAR) of irrigation water in US salinity diagram (dry and wet season).

Permeability index

The PI values were between 37.21 and 50.63 in the dry season, and between 34.99 and 53.54 in the wet season. All samples fall into the ‘Suitable’ category for irrigation in dry and wet seasons (Table 12).

Sodium percentage

In all natural waters, sodium percentage (%Na) content is one of the most important parameters to assess their suitability for agricultural purposes. This is because sodium increases the hardness of the soil, and decreases its permeability (Varol & Davraz 2015). This soil type prevents plant growth. Sodium percentage values of groundwater samples were calculated for the dry and wet seasons (Table 12). Sodium percentage of these samples was plotted against EC in a Wilcox diagram (Figure 6) and given in Table 12. According to the Wilcox diagram, 86% of all samples were in the ‘Excellent to good’ irrigation water class and 13% (K4, K13) were in the ‘Good to permissible’ irrigation water class in the dry and wet seasons.

Figure 6

According to the Wilcox (1955) diagram, irrigational suitability of groundwater in the dry and wet season.

Figure 6

According to the Wilcox (1955) diagram, irrigational suitability of groundwater in the dry and wet season.

Magnesium hazard

Paliwal (1972) introduced a ratio MH for assessing the suitability of irrigation water quality. Generally, Ca and Mg maintain a state of equilibrium in water. Magnesium damages the soil structure when water contains more Na and is highly saline. Generally, a high concentration of Mg is caused by the exchange of Na in irrigated soils. In equilibrium, the high Mg concentration can affect soil quality by changing its alkalinity. Thus, this situation affects crop yields (Varol & Davraz 2015). The MH values in the study area ranged from 41.51 to 68.04 and 53.33% of the samples were considered suitable for irrigation, the remainder of samples being considered unsuitable for irrigation owing to their adverse effect on crop yields in the dry and wet seasons (Table 12).

Residual sodium carbonate

RSC is an important parameter for the suitability of irrigation water (Siddiqui et al. 2005; Varol & Davraz 2015). Excessive magnesium and calcium ions tend to precipitate as carbonate. The sodium concentration is increased and fixed to the soil and thus the soil permeability is reduced. The high RSC value in water causes an increase in the adsorption of sodium in the soil (Eaton 1950; Selvakumar et al. 2017). Lloyd & Heathcote (1985) have classified irrigation water based on RSC as suitable (<1.25), marginal (1.25–2.5) and unsuitable (>2.5). According to RSC values, 100% of groundwater samples were suitable for irrigation in dry and wet seasons (Table 12).

Evaluation of water quality for industry

Quality classifications for industrial water usage lie within a wide range and nearly every industrial unit has its own standards. Industries often have problems with the chemical reactions associated with poor water quality, such as incrustation and corrosion. Incrustation involves the deposition of undesirable CaCO3 on metal surfaces, whereas corrosion is a chemical process which causes the metals to wear out. For this reason, industrial use of water in the study area has also been examined in this study. The following water quality criteria were adopted when classifications were made (Johnson 1983; Subba Rao et al. 2012; Varol & Davraz 2015): (a) if water contains 400 mg/L of excess HCO3 or 100 mg/L of excess SO4, it may cause incrustation; (b) if water contains pH< 7, TDS more than 1,000 mg/L or Cl more than 500 mg/L, this water may cause corrosion.

In the present study, about 53.33% of the HCO3 concentrations of the samples (K1, K2, K4, K5, K7, K11, K12 and K13) exceeded the limit of 400 mg/L in dry and wet seasons. Also, in 13.33% of the samples (K4 and K13), the SO4 concentrations were more than 100 mg/L in dry and wet seasons. According to these results, the mentioned samples can induce incrustation on metal surfaces and are therefore not recommended for industrial use.

If the groundwater pH > 7, TDS is less than 1,000 mg/L and Cl is less than 500 mg/L, there is no corrosion effect. Therefore, there is no corrosion effect for any waters in the study areas.

Health risk assessment

Risk assessment is an effort to identify and measure the effects of various pollutants on human health. It also includes evaluating toxicity data for human exposure to chemicals and estimating the potential exposure levels. There are three main routes to of exposure: ingestion, inhalation, and dermal absorption. Only the ingestion path was taken into account in this study due to its being the most common form of exposure to trace elements (Varol & Davraz 2016).

Generally, local people in the study area use both groundwater and tap water for drinking and domestic purposes. Therefore the water resources in this study, with regard to WHO (2011) and TSI 266 (2005) standards, exceed the safe limits of concentration for NO3, As and Cr and could be the origin of problematic health effects (Tables 13 and 14). We evaluated the origin of these problems and their effects on health. The NO3, As and Cr concentrations in drinking water have been used to calculate potential health risk assessments: chronic and carcinogenic effects such as average daily dose (ADD), HQ noncancer and carcinogenic risk (R cancer). The calculated health risk for residents is presented in Tables 13 and 14.

Table 13

Calculated carcinogenic and noncarcinogenic risk of drinking water (dry season)

Substance Water sample no. C (mg/l) IR (l/day) ED (years) EF days/years BW (kg) AT (days) ADD (mg/kg) *RfD (mg/kg/d) *CSF (mg/kg/d)-1 R cancer HQ noncancer (TSI 266) (2005) (mg/l) WHO (2011) standards (mg/l) 
NO3 K1 27.90 30 365 70 10950 0.80 1.60 – – 0.50 50 50 
K2 31.40 30 365 70 10950 0.90 1.60 – – 0.56 
K3 5.57 30 365 70 10950 0.16 1.60 – – 0.10 
K4 23.78 30 365 70 10950 0.68 1.60 – – 0.42 
K5 37.34 30 365 70 10950 1.07 1.60 – – 0.67 
K6 5.65 30 365 70 10950 0.16 1.60 – – 0.10 
K7 23.04 30 365 70 10950 0.66 1.60 – – 0.41 
K8 17.19 30 365 70 10950 0.49 1.60 – – 0.31 
K9 13.60 30 365 70 10950 0.39 1.60 – – 0.24 
K10 5.84 30 365 70 10950 0.17 1.60 – – 0.10 
K11 25.62 30 365 70 10950 0.73 1.60 – – 0.46 
K12 27.71 30 365 70 10950 0.79 1.60 – – 0.49 
K13 21.78 30 365 70 10950 0.62 1.60 – – 0.39 
K14 13.32 30 365 70 10950 0.38 1.60 – – 0.24 
K15 19.37 30 365 70 10950 0.55 1.60 – – 0.35 
As K1 0.08 30 365 70 10950 0.00 3.10−4 1.5 0.00 7.62 0.01 0.01 
K2 0.12 30 365 70 10950 0.00 3.10−4 1.5 0.01 11.43 
K3 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.48 
K4 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.48 
K5 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.38 
K6 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.29 
K7 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.29 
K8 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.38 
K9 0.17 30 365 70 10950 0.00 3.10−4 1.5 0.01 16.19 
K10 0.14 30 365 70 10950 0.00 3.10−4 1.5 0.01 13.33 
K11 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.29 
K12 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.38 
K13 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.29 
K14 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.48 
K15 0.14 30 365 70 10950 0.00 3.10−4 1.5 0.01 13.33 
Cr K1 0.05 30 365 70 10950 0.00 3.10−3 – – 0.48 0.05 – 
K2 0.04 30 365 70 10950 0.00 3.10−3 – – 0.38 
K3 0.01 30 365 70 10950 0.00 3.10−3 – – 0.10 
K4 0.07 30 365 70 10950 0.00 3.10−3 – – 0.67 
K5 0.06 30 365 70 10950 0.00 3.10−3 – – 0.57 
K6 0.01 30 365 70 10950 0.00 3.10−3 – – 0.10 
K7 0.04 30 365 70 10950 0.00 3.10−3 – – 0.38 
K8 0.02 30 365 70 10950 0.00 3.10−3 – – 0.19 
K9 0.02 30 365 70 10950 0.00 3.10−3 – – 0.19 
K10 0.01 30 365 70 10950 0.00 3.10−3 – – 0.10 
K11 0.05 30 365 70 10950 0.00 3.10−3 – – 0.48 
K12 0.05 30 365 70 10950 0.00 3.10−3 – – 0.48 
K13 0.06 30 365 70 10950 0.00 3.10−3 – – 0.57 
K14 0.02 30 365 70 10950 0.00 3.10−3 – – 0.19 
K15 0.03 30 365 70 10950 0.00 3.10−3 – – 0.29 
Substance Water sample no. C (mg/l) IR (l/day) ED (years) EF days/years BW (kg) AT (days) ADD (mg/kg) *RfD (mg/kg/d) *CSF (mg/kg/d)-1 R cancer HQ noncancer (TSI 266) (2005) (mg/l) WHO (2011) standards (mg/l) 
NO3 K1 27.90 30 365 70 10950 0.80 1.60 – – 0.50 50 50 
K2 31.40 30 365 70 10950 0.90 1.60 – – 0.56 
K3 5.57 30 365 70 10950 0.16 1.60 – – 0.10 
K4 23.78 30 365 70 10950 0.68 1.60 – – 0.42 
K5 37.34 30 365 70 10950 1.07 1.60 – – 0.67 
K6 5.65 30 365 70 10950 0.16 1.60 – – 0.10 
K7 23.04 30 365 70 10950 0.66 1.60 – – 0.41 
K8 17.19 30 365 70 10950 0.49 1.60 – – 0.31 
K9 13.60 30 365 70 10950 0.39 1.60 – – 0.24 
K10 5.84 30 365 70 10950 0.17 1.60 – – 0.10 
K11 25.62 30 365 70 10950 0.73 1.60 – – 0.46 
K12 27.71 30 365 70 10950 0.79 1.60 – – 0.49 
K13 21.78 30 365 70 10950 0.62 1.60 – – 0.39 
K14 13.32 30 365 70 10950 0.38 1.60 – – 0.24 
K15 19.37 30 365 70 10950 0.55 1.60 – – 0.35 
As K1 0.08 30 365 70 10950 0.00 3.10−4 1.5 0.00 7.62 0.01 0.01 
K2 0.12 30 365 70 10950 0.00 3.10−4 1.5 0.01 11.43 
K3 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.48 
K4 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.48 
K5 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.38 
K6 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.29 
K7 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.29 
K8 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.38 
K9 0.17 30 365 70 10950 0.00 3.10−4 1.5 0.01 16.19 
K10 0.14 30 365 70 10950 0.00 3.10−4 1.5 0.01 13.33 
K11 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.29 
K12 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.38 
K13 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.29 
K14 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.48 
K15 0.14 30 365 70 10950 0.00 3.10−4 1.5 0.01 13.33 
Cr K1 0.05 30 365 70 10950 0.00 3.10−3 – – 0.48 0.05 – 
K2 0.04 30 365 70 10950 0.00 3.10−3 – – 0.38 
K3 0.01 30 365 70 10950 0.00 3.10−3 – – 0.10 
K4 0.07 30 365 70 10950 0.00 3.10−3 – – 0.67 
K5 0.06 30 365 70 10950 0.00 3.10−3 – – 0.57 
K6 0.01 30 365 70 10950 0.00 3.10−3 – – 0.10 
K7 0.04 30 365 70 10950 0.00 3.10−3 – – 0.38 
K8 0.02 30 365 70 10950 0.00 3.10−3 – – 0.19 
K9 0.02 30 365 70 10950 0.00 3.10−3 – – 0.19 
K10 0.01 30 365 70 10950 0.00 3.10−3 – – 0.10 
K11 0.05 30 365 70 10950 0.00 3.10−3 – – 0.48 
K12 0.05 30 365 70 10950 0.00 3.10−3 – – 0.48 
K13 0.06 30 365 70 10950 0.00 3.10−3 – – 0.57 
K14 0.02 30 365 70 10950 0.00 3.10−3 – – 0.19 
K15 0.03 30 365 70 10950 0.00 3.10−3 – – 0.29 

*Data from USEPA (2005).

Table 14

Calculated carcinogenic and noncarcinogenic risk of drinking water (wet season)

Substance Water sample no. C (mg/l) IR (l/day) ED (years) EF days/years BW (kg) AT (30×365 days) ADD (mg/kg) *RfD (mg/kg/d) *CSF (mg/kg/d)-1 R cancer HQ noncancer (TSI 266) (2005) (mg/l) WHO (2011) standards (mg/l) 
NO3 K1 47.7 30 365 70 10950 1.36 1.60 – – 0.85 50 50 
K2 51 30 365 70 10950 1.46 1.60 – – 0.91 
K3 7.32 30 365 70 10950 0.21 1.60 – – 0.13 
K4 35.25 30 365 70 10950 1.01 1.60 – – 0.63 
K5 52.14 30 365 70 10950 1.49 1.60 – – 0.93 
K6 4.9 30 365 70 10950 0.14 1.60 – – 0.09 
K7 50.02 30 365 70 10950 1.43 1.60 – – 0.89 
K8 27.08 30 365 70 10950 0.77 1.60 – – 0.48 
K9 20.5 30 365 70 10950 0.59 1.60 – – 0.37 
K10 7.31 30 365 70 10950 0.21 1.60 – – 0.13 
K11 36.43 30 365 70 10950 1.04 1.60 – – 0.65 
K12 20.12 30 365 70 10950 0.57 1.60 – – 0.36 
K13 33.54 30 365 70 10950 0.96 1.60 – – 0.60 
K14 10.28 30 365 70 10950 0.29 1.60 – – 0.18 
K15 28.69 30 365 70 10950 0.82 1.60 – – 0.51 
As K1 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.08 0.01 0.01 
K2 0.09 30 365 70 10950 0.00 3.10−4 1.5 0.00 8.72 
K3 0.09 30 365 70 10950 0.00 3.10−4 1.5 0.00 8.95 
K4 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.80 
K5 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.64 
K6 0.10 30 365 70 10950 0.00 3.10−4 1.5 0.00 9.43 
K7 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.72 
K8 0.17 30 365 70 10950 0.00 3.10−4 1.5 0.01 16.17 
K9 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.44 
K10 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.20 
K11 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.73 
K12 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.23 
K13 0.17 30 365 70 10950 0.00 3.10−4 1.5 0.01 16.44 
K14 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.52 
K15 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.00 
Cr K1 0.06 30 365 70 10950 0.00 3.10−3 – – 0.59 0.05 – 
K2 0.05 30 365 70 10950 0.00 3.10−3 – – 0.48 
K3 0.01 30 365 70 10950 0.00 3.10−3 – – 0.13 
K4 0.08 30 365 70 10950 0.00 3.10−3 – – 0.75 
K5 0.05 30 365 70 10950 0.00 3.10−3 – – 0.45 
K6 0.01 30 365 70 10950 0.00 3.10−3 – – 0.11 
K7 0.05 30 365 70 10950 0.00 3.10−3 – – 0.47 
K8 0.03 30 365 70 10950 0.00 3.10−3 – – 0.30 
K9 0.04 30 365 70 10950 0.00 3.10−3 – – 0.34 
K10 0.03 30 365 70 10950 0.00 3.10−3 – – 0.30 
K11 0.07 30 365 70 10950 0.00 3.10−3 – – 0.62 
K12 0.06 30 365 70 10950 0.00 3.10−3 – – 0.60 
K13 0.07 30 365 70 10950 0.00 3.10−3 – – 0.68 
K14 0.03 30 365 70 10950 0.00 3.10−3 – – 0.25 
K15 0.03 30 365 70 10950 0.00 3.10−3 – – 0.32 
Substance Water sample no. C (mg/l) IR (l/day) ED (years) EF days/years BW (kg) AT (30×365 days) ADD (mg/kg) *RfD (mg/kg/d) *CSF (mg/kg/d)-1 R cancer HQ noncancer (TSI 266) (2005) (mg/l) WHO (2011) standards (mg/l) 
NO3 K1 47.7 30 365 70 10950 1.36 1.60 – – 0.85 50 50 
K2 51 30 365 70 10950 1.46 1.60 – – 0.91 
K3 7.32 30 365 70 10950 0.21 1.60 – – 0.13 
K4 35.25 30 365 70 10950 1.01 1.60 – – 0.63 
K5 52.14 30 365 70 10950 1.49 1.60 – – 0.93 
K6 4.9 30 365 70 10950 0.14 1.60 – – 0.09 
K7 50.02 30 365 70 10950 1.43 1.60 – – 0.89 
K8 27.08 30 365 70 10950 0.77 1.60 – – 0.48 
K9 20.5 30 365 70 10950 0.59 1.60 – – 0.37 
K10 7.31 30 365 70 10950 0.21 1.60 – – 0.13 
K11 36.43 30 365 70 10950 1.04 1.60 – – 0.65 
K12 20.12 30 365 70 10950 0.57 1.60 – – 0.36 
K13 33.54 30 365 70 10950 0.96 1.60 – – 0.60 
K14 10.28 30 365 70 10950 0.29 1.60 – – 0.18 
K15 28.69 30 365 70 10950 0.82 1.60 – – 0.51 
As K1 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.08 0.01 0.01 
K2 0.09 30 365 70 10950 0.00 3.10−4 1.5 0.00 8.72 
K3 0.09 30 365 70 10950 0.00 3.10−4 1.5 0.00 8.95 
K4 0.11 30 365 70 10950 0.00 3.10−4 1.5 0.00 10.80 
K5 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.64 
K6 0.10 30 365 70 10950 0.00 3.10−4 1.5 0.00 9.43 
K7 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.72 
K8 0.17 30 365 70 10950 0.00 3.10−4 1.5 0.01 16.17 
K9 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.44 
K10 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.20 
K11 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.73 
K12 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.23 
K13 0.17 30 365 70 10950 0.00 3.10−4 1.5 0.01 16.44 
K14 0.13 30 365 70 10950 0.00 3.10−4 1.5 0.01 12.52 
K15 0.15 30 365 70 10950 0.00 3.10−4 1.5 0.01 14.00 
Cr K1 0.06 30 365 70 10950 0.00 3.10−3 – – 0.59 0.05 – 
K2 0.05 30 365 70 10950 0.00 3.10−3 – – 0.48 
K3 0.01 30 365 70 10950 0.00 3.10−3 – – 0.13 
K4 0.08 30 365 70 10950 0.00 3.10−3 – – 0.75 
K5 0.05 30 365 70 10950 0.00 3.10−3 – – 0.45 
K6 0.01 30 365 70 10950 0.00 3.10−3 – – 0.11 
K7 0.05 30 365 70 10950 0.00 3.10−3 – – 0.47 
K8 0.03 30 365 70 10950 0.00 3.10−3 – – 0.30 
K9 0.04 30 365 70 10950 0.00 3.10−3 – – 0.34 
K10 0.03 30 365 70 10950 0.00 3.10−3 – – 0.30 
K11 0.07 30 365 70 10950 0.00 3.10−3 – – 0.62 
K12 0.06 30 365 70 10950 0.00 3.10−3 – – 0.60 
K13 0.07 30 365 70 10950 0.00 3.10−3 – – 0.68 
K14 0.03 30 365 70 10950 0.00 3.10−3 – – 0.25 
K15 0.03 30 365 70 10950 0.00 3.10−3 – – 0.32 

*Data from USEPA (2005).

According to Tables 13 and 14, the values of ADD were between 0.16–1.07 (mg/kg) in the dry season and 0.21–1.49 (mg/kg) in the wet season for NO3. The values of ADD were 0.00 (mg/kg) in the dry season and 0.09 and 0.17 mg/kg in the wet season for As. The values of ADD were 0.00 (mg/kg) in dry season and wet season the wet season for Cr. The values of HQnoncancer were 0.10–0.67 in the dry season and 0.13–0.93 in the wet season for NO3. For As, the values of HQnoncancer were between 7.62–16.19 in the dry season and 8.72–16.44 in the wet season. For Cr, the values of HQnoncancer were 0.10–0.67 in the dry season and 0.11–0.75 in the wet season. Also, values of Rcancer, were 0.00–0.01 in the dry season and 0.13–0.25 in the wet season for As. Carcinogenic risk is the likelihood of developing any type of cancer against the risk of exposure to a substance that has a life-long toxic effect on a person. Acceptable or tolerable risk, as determined by the regulators of the subject, is in the range of 10−6 to 10−4 (USEPA 2000; WHO 2004; Muhammad et al. 2010).

According to Tables 13 and 14, the possibility of developing cancer is 1–2 patients out of every 10 healthy people in dry and wet seasons. Excessive consumption of water with a high concentration of As in the study area carries a high risk of cancer. In addition, there is a high risk of noncarcinogenic effects in terms of As. Furthermore, according to Turkish drinking water standards, concentrations of heavy metals (As and Cr) in water were evaluated in dry and wet seasons, and they also exceeded the limit values (Tables 13 and 14). This also supports the results of the health risk assessment. For this reason, it is an urgent requirement to develop more efficient As removal methods in this emerging situation. These results show that the study area is at high risk in terms of health. This is an alarming situation and there is a need to develop more effective arsenic removal methods and urgent remediation to protect the health of at-risk people in the study area.

CONCLUSIONS

Groundwater quality and its suitability for different uses such as drinking, agriculture and industry in Korkuteli district were evaluated because groundwater is a major resource for domestic, agricultural, and industrial activities in the study area. In this study, a total of 30 water samples taken from wells, springs, and tap waters were analyzed in dry and wet seasons. The hydrogeochemical and water quality studies conducted in the groundwater of the Korkuteli district provides the following conclusions.

The seasonal variation of physical, major ion and heavy metal and pollutant concentrations of the water resources in the study area were evaluated. As a result, changes in the physical and major ion concentrations of the water are associated with rock–water interactions. However, changes in the concentrations of heavy metals and nitrogen derivatives in the water are also related to anthropogenic inputs. In the wet season, infiltration of rain water changes the concentration values.

Statistical analyses were carried out to determine the hydrochemical properties of groundwater and tap water in the study area, and their relationships with each other. The correlation analysis is a bivariate method that is applied to describe the degree of relationship between two hydrochemical parameters in dry and wet seasons. The parameters used for correlation analysis were T (°C), pH, Eh, EC, TDS, Ca, Mg, Na, K, HCO3, CO3, Cl, SO4, NO3, NO2, NH4, Al, As, Cu, Cr, Fe and Zn values of water. There was a moderate to strong correlation between some of the correlation groups in the study area (r > 0.7). The reason for this is considered to be mainly the dissolution/precipitation reactions, concentration effects and anthropogenic inputs, in relation to the simultaneous increase/decrease in cations.

Ca-Mg-HCO3 and Mg-Ca-HCO3 were the dominant water types observed in dry and wet seasons, due to water–rock interaction in the study area. According to the Gibbs diagrams, samples from both seasons fell in the rock-dominance zone, suggesting precipitation induced chemical weathering along with dissolution of rock forming minerals.

The WQI was applied to determine the drinking water quality of the water samples in the study area. According to the WQI, in the dry season, 100% of groundwater samples represent ‘Poor water’ and during the wet season 93.33% of groundwater samples represent ‘Poor water’ and 6.66% indicate ‘Very Poor water’. This indicates that the quality of wet season samples is very bad. The increase in ion concentrations is related to the infiltration of rain water in the farmland. In addition, nitrogen derivatives and heavy metal concentrations of water samples were compared and assessed with the limit values determined by the World Health Organization (WHO 2011) for the usability of drinking water. Accordingly, it is not appropriate to use as drinking water in terms of the heavy metal and nitrogen derivatives analysis results.

In addition, use as irrigation water in the study area was evaluated by SAR, PI, Na%, MH, RSC, USSL classification and Wilcox diagram. A large majority of water samples were suitable for irrigation purposes according to RSC, SAR, PI and Na%. According to the MH values, 53.33% of the samples were considered suitable for irrigation; meanwhile, 46.66% of samples were considered unsuitable for irrigation indicating their adverse effect on crop yields in the dry and wet seasons.

The groundwater quality was evaluated in terms of industrial usage. Because some water types can cause incrustation and corrosion on metal surfaces, they cannot be used. Therefore, HCO3, SO4, pH, TDS and Cl concentrations of waters were evaluated. According to HCO3 and SO4 results, the studied samples can induce incrustation on metal surfaces and are not recommended for industrial use. But there are no corrosion effects from any waters in terms of pH, TDS and Cl concentrations in the study area.

The health risk assessment for NO3, As and Cr (separately for dry and wet seasons) was carried out on the grounds. The arsenic concentrations exceeded the limit values. According to the health risk assessment, the study area is categorized as a high risk area.

As a result, the use of Korkuteli district center water resources is not suitable as drinking water. Use of these waters as drinking water will affect human health negatively. Taking this into consideration, precautions must be taken.

ACKNOWLEDGEMENTS

This work was supported by the Research Fund of the Suleyman Demirel University. Project number: 4720-YL1-16. The support of the General Directorate of State Hydraulic Works (SHW) XVIII Regional Directorate, Isparta is gratefully acknowledged.

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