An attempt has been made to assess the water quality of the Danube River using water quality inde... more An attempt has been made to assess the water quality of the Danube River using water quality index technique. In this study, the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) was selected to express the quality of water for drinking water abstraction and to provide information on the spatial and temporal variations of the river water quality. Water quality of 13 parameters has been considered in four sampling stations during 1-year period. The European Community (EC) standards for drinking water abstraction were used for CCME WQI calculation. The water quality variables included in the index are dissolved oxygen, biochemical oxygen demand, ammonium, nitrates, total phosphorus, water temperature, pH, total suspended solids, cadmium, copper, chromium, nickel and lead. The results revealed that the water quality was found fair in all sampling stations except one station, which was marginal. It was observed that the most important variables that affected the water quality were ammonium, total phosphorous, water temperature and total suspended solids. Moreover, no significant changes were observed for temporal variation in the Danube river water quality. The CCME WQI gave reasonable results and introduced representative outcomes of the raw data of the river.
The present paper aimed at assessing the hydrochemistry and the water quality of the groundwater ... more The present paper aimed at assessing the hydrochemistry and the water quality of the groundwater in the urban area of Baghdad. Sixty-six groundwater samples were collected from shallow tube wells and analyzed for pH, total dissolved solids (TDS), electrical conductivity (EC), calcium, magnesium, sodium, potassium, chloride, bicarbonate, carbonate, sulfate and nitrate. Groundwater suitability for drinking was evaluated based on the World Health Organization (WHO) and Iraqi standards, whereas suitability of groundwater for irrigation was evaluated based on various hydrochemical parameters and methods, such as sodium adsorption ratio (SAR), residual sodium carbonate (RSC), sodium percentage (%Na), United States salinity diagram, Wilcox's diagram and magnesium hazards (MH). Results showed that the urban area of Baghdad is highly affected by the anthropogenic sources. Based on Piper diagram, the groundwater in the study area are classified into two water types (NaCl and CaCl), indicating high-salinity water. Gibbs ratio indicates that the majority of the groundwater in the study area is affected by the evaporation process. Furthermore, the ion exchange process revealed that 85% of the groundwater samples indicate chloro-alkaline disequilibrium. Moreover, it was found that all the groundwater samples are unsuitable for both drinking and irrigation purposes.
IOP Conference Series: Materials Science and Engineering, 2019
Eichhornia, or water hyacinth represents a serious threat to potable water basins. This problem i... more Eichhornia, or water hyacinth represents a serious threat to potable water basins. This problem is materialized majorly in consuming large amounts of water and dissolved Oxygen that is necessary for aquatic life, and minorly in hindering water streams. Even there are limited trials to overcome such pests, none of them presents an acceptable solution economically and logically. Chlorine is a well-known biocide and broadly used in water industry. It could give a possible method to fight such weed. To investigate that, concentration-time plot should be introduced similar to any other microorganisms; especially, bacteria in water. In this work, various doses of Chlorine along various time periods were examined as an introductory to prescribe an adequate method to deal with such water disaster which can severely attack water resources.
Environmental Engineering and Management Journal, 2019
In this paper, six different water quality indices were selected to assess the water quality for ... more In this paper, six different water quality indices were selected to assess the water quality for different uses and to identify the suitability of the selected indices in the assessment of the Danube River through a comprehensive comparison, in addition, to provide information on the spatial and temporal variations of the river water quality. The selected water quality indices are the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), Oregon Water Quality Index (OWQI), Aquatic Toxicity Index (ATI), Universal Water Quality Index (UWQI), Overall Index of Pollution (OIP) and the Bascaron Water Quality Index (BWQI). Water quality dataset of 13 parameters obtained from 4 sampling points during a one-year monitoring period was considered in this study. The results demonstrated that the CCME WQI gave reasonable results in comparison to the raw data of the Danube River. The results of the other indices did not introduce representative outcomes of the raw data of the river. It was observed that some of these indices were biased and others have an eclipsing problem. However, these indices may be applicable to other water bodies.
IOP Conf. Series: Materials Science and Engineering, 2019
The assessment of the quality of tap water is very important to explore its fit for drinking, esp... more The assessment of the quality of tap water is very important to explore its fit for drinking, especially for developing countries. In the present paper, tap water quality evaluation has been carried out in the Balad city, Salah Al-Din Governorate, Iraq. A total of 17 tap water samples were collected from the city and analysed for various physicochemical and biological parameters, namely, pH, total dissolved solids (TDS), electrical conductivity (EC), turbidity, total hardness (TH), calcium magnesium, chloride and total coliform (TC). Suitability of water for drinking was evaluated based on the World Health Organization (WHO) and Iraqi standards. Spot maps were also generated using GIS to identify the spatial distribution of tap water quality parameters. The results revealed that the tap water is fit for drinking purpose regarding bacteriological pollution. Physicochemical parameters concentration of water samples were within standards except for turbidity. This parameter was highly exceeding the limits (5 NTU) in all tap water samples. Generally, tap water in the Balad city may pose risks to the health of people using it for drinking purposes. Moreover, cluster analysis revealed that the distribution system might affect the quality of tap water in the study area.
The assessment of hydrochemical quality of groundwater is very important to explore its nature an... more The assessment of hydrochemical quality of groundwater is very important to explore its nature and usefulness. In this paper, groundwater quality evaluation is carried out in the Balad district, Salah Al-Din Governorate, Iraq. A total of 28 groundwater samples are collected from shallow tube wells and analyzed for various physicochemical parameters. Groundwater suitability for drinking is evaluated based on the World Health Organization (WHO) and Iraqi standards, and suitability of groundwater for irrigation is assessed based on various hydrochemical parameters. The results reveal that the dominant types of groundwater based on piper diagram are mixed CaMgCl and CaCl. Gibbs ratio indicates that the groundwater in the studied area is affected by the evaporation process. The cation-anion exchange reaction in the studied area demonstrates that 54% of the groundwater samples indicate a direct base (cation-anion) exchange reaction, while 46% of the groundwater samples indicating the chloro-alkaline disequilibrium. Furthermore, generally all of the groundwater samples are unsuitable for drinking and irrigation. Cluster analysis reveals two different groups of similarities between the groundwater samples, reflecting different pollution levels in the studied area.
The present work suggests a simple approach for simulating the dispersion of pollutants in rivers... more The present work suggests a simple approach for simulating the dispersion of pollutants in rivers and streams with the aid of computational fluid dynamics technique. The two-dimensional advection–dispersion equation was solved using FlexPDE code to predict the biochemical oxygen demand (BOD) and the total dissolved solids (TDS) concentrations at the confluence of Diyala with Tigris Rivers. In this model, two sets of data were used for calibration and validation processes. Various values of longitudinal and transverse dispersion coefficients were adopted in the model to determine the suitable value using the trial-and-error method. The results revealed that the best agreement between simulated and measured values was observed when the longitudinal and transverse dispersion coefficients are close to 10 and 5 m 2 /s, respectively. The results showed that the proposed methodology is more suitable for TDS, while for BOD, it needs an accurate representation of the chemical or biological transformations. Keywords Pollutant transport · Diyala River · Tigris River · Water quality · FlexPDE
An attempt has been made to study the effects of the Jidostita tributary as point source pollutio... more An attempt has been made to study the effects of the Jidostita tributary as point source pollution on the Biochemical oxygen demand concentration in the Danube River, Romania. A numerical solution was introduced and solved using FlexPDE software. In this paper, three different scenarios of dispersion of BOD along the Danube River were examined by setting different values of river velocity. The temporal variations in simulation of BOD concentration were insignificant in this study and only spatial variations were considered. The results revealed that the BOD concentration at Gura Văii is about 3.4 mg/L in the first case, whereas, the BOD concentration at Gura Văii is about 3 mg/L in the second case and the BOD concentration at Gura Văii is about 2.5 mg/L in the third case. The BOD concentrations were dispersed to less than 0.5 mg/L at Schela Cladovei station in all cases (scenarios). The result of the simulated BOD concentration along the river was in agreement with observed BOD concentration. Therefore, FlexPDE solver can be used as a useful tool for predicting pollution dispersion and provide a good basis for future river water quality policy options for limiting of the pollutant sources.
Multivariate statistical methods such as factor analysis (FA) and cluster analysis (CA) were appl... more Multivariate statistical methods such as factor analysis (FA) and cluster analysis (CA) were applied to identify the main factors and pollution sources affecting on the water quality of Danube River and to evaluate spatial and temporal similarities or dissimilarities among the sampling sites and monitoring periods. Water quality of 14 parameters has been considered in four sampling stations during 1 year period. The results of factor analysis specified three factors representing 64.369% of the total variance in water quality. The main differences are related to domestic wastewater, industrial discharge, and agriculture activities from agricultural area. Hierarchical spatial CA revealed two different groups of similarities between the sampling sites, reflecting different pollution levels in the river water quality. Hierarchical temporal CA showed that the temporal variations in the river water are not relying on the local climate.
The main aim of the study was to explore the applicability of the one-dimensional (1D) steady sta... more The main aim of the study was to explore the applicability of the one-dimensional (1D) steady state model (QUAL2K) for simulating the water quality in large river. Danube River at lower Danube course was chosen as a case study. The model was calibrated using data on April, 2008 (spring season). Validation of the model was performed using data on September, 2008 (autumn season). Moreover, four different scenarios were examined to control the level of CBOD and DO in the river. The model output revealed that the calibration and validation results were in agreement with the observed values, with some exceptions. Although QUAL2K is one-dimensional steady state model, the simulated results were compatible with previous technical reports. Thus, it can be used as a suitable tool for simulating the water quality in large rivers.
Iraq's agricultural sector suffers from the salinity problem of agricultural land which reflects ... more Iraq's agricultural sector suffers from the salinity problem of agricultural land which reflects negatively on the production of field crops and agricultural land investment, particularly in the governorates geographically located in the sedimentary plain. The management of salinity problems facing by the agricultural sector has become crucial priorities for the Iraqi government. In this study, SWOT analysis was applied to suggest proper strategies that might be followed to solve the problem of salinity. After the internal and external factors have been identified, 17 strategies planning was developed. Internal–External Matrix (IE matrix) was used to select the appropriate type of strategy. Based on the results of Internal–External Matrix, government should consider the conservative strategies. Quantitative Strategic Planning Matrix (QSPM) was also used in this study. By applying the QSPM, re-arrangement of the proposed strategies has been made by importance and priority. The first three suggested strategies in term of importance and priority were establishment of the National Center for Agricultural Policy, investing in improved irrigation systems such sprinkler and drip irrigation and innovative agricultural technologies to control salinity are urgent.
ABSTRACT
An attempt has been made to assess the overall groundwater quality and identify major va... more ABSTRACT An attempt has been made to assess the overall groundwater quality and identify major variables affecting the groundwater quality in the urban area of Baghdad, Iraq. Groundwater samples from tube wells of 66 sampling sites were analyzed for the major physicochemical variables during May 2010. From the Hill–Piper trilinear diagram, it is observed that the majority of ground water from sampling sites are Ca -Mg -Cl- SO4 type and Na -K -Cl -SO4 type water. Multivariate statistical techniques such as factor analysis and cluster analysis were applied to identify the major factors (variables) corresponding to the different source of variation in groundwater quality of Baghdad. Factor analysis identified three major factor explaining 82.506% of the total variance in water quality; and the major variations are related to degree of mineralization of the geological components of soils, irrigation return flow, agricultural activities and mixing of wastewater. Hierarchical cluster analysis revealed three different groups of similarities between the sampling sites, reflecting different physico-chemical properties and pollution levels in the groundwater quality.
An attempt has been made to assess the water quality of the Danube River using water quality inde... more An attempt has been made to assess the water quality of the Danube River using water quality index technique. In this study, the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) was selected to express the quality of water for drinking water abstraction and to provide information on the spatial and temporal variations of the river water quality. Water quality of 13 parameters has been considered in four sampling stations during 1-year period. The European Community (EC) standards for drinking water abstraction were used for CCME WQI calculation. The water quality variables included in the index are dissolved oxygen, biochemical oxygen demand, ammonium, nitrates, total phosphorus, water temperature, pH, total suspended solids, cadmium, copper, chromium, nickel and lead. The results revealed that the water quality was found fair in all sampling stations except one station, which was marginal. It was observed that the most important variables that affected the water quality were ammonium, total phosphorous, water temperature and total suspended solids. Moreover, no significant changes were observed for temporal variation in the Danube river water quality. The CCME WQI gave reasonable results and introduced representative outcomes of the raw data of the river.
The present paper aimed at assessing the hydrochemistry and the water quality of the groundwater ... more The present paper aimed at assessing the hydrochemistry and the water quality of the groundwater in the urban area of Baghdad. Sixty-six groundwater samples were collected from shallow tube wells and analyzed for pH, total dissolved solids (TDS), electrical conductivity (EC), calcium, magnesium, sodium, potassium, chloride, bicarbonate, carbonate, sulfate and nitrate. Groundwater suitability for drinking was evaluated based on the World Health Organization (WHO) and Iraqi standards, whereas suitability of groundwater for irrigation was evaluated based on various hydrochemical parameters and methods, such as sodium adsorption ratio (SAR), residual sodium carbonate (RSC), sodium percentage (%Na), United States salinity diagram, Wilcox's diagram and magnesium hazards (MH). Results showed that the urban area of Baghdad is highly affected by the anthropogenic sources. Based on Piper diagram, the groundwater in the study area are classified into two water types (NaCl and CaCl), indicating high-salinity water. Gibbs ratio indicates that the majority of the groundwater in the study area is affected by the evaporation process. Furthermore, the ion exchange process revealed that 85% of the groundwater samples indicate chloro-alkaline disequilibrium. Moreover, it was found that all the groundwater samples are unsuitable for both drinking and irrigation purposes.
IOP Conference Series: Materials Science and Engineering, 2019
Eichhornia, or water hyacinth represents a serious threat to potable water basins. This problem i... more Eichhornia, or water hyacinth represents a serious threat to potable water basins. This problem is materialized majorly in consuming large amounts of water and dissolved Oxygen that is necessary for aquatic life, and minorly in hindering water streams. Even there are limited trials to overcome such pests, none of them presents an acceptable solution economically and logically. Chlorine is a well-known biocide and broadly used in water industry. It could give a possible method to fight such weed. To investigate that, concentration-time plot should be introduced similar to any other microorganisms; especially, bacteria in water. In this work, various doses of Chlorine along various time periods were examined as an introductory to prescribe an adequate method to deal with such water disaster which can severely attack water resources.
Environmental Engineering and Management Journal, 2019
In this paper, six different water quality indices were selected to assess the water quality for ... more In this paper, six different water quality indices were selected to assess the water quality for different uses and to identify the suitability of the selected indices in the assessment of the Danube River through a comprehensive comparison, in addition, to provide information on the spatial and temporal variations of the river water quality. The selected water quality indices are the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), Oregon Water Quality Index (OWQI), Aquatic Toxicity Index (ATI), Universal Water Quality Index (UWQI), Overall Index of Pollution (OIP) and the Bascaron Water Quality Index (BWQI). Water quality dataset of 13 parameters obtained from 4 sampling points during a one-year monitoring period was considered in this study. The results demonstrated that the CCME WQI gave reasonable results in comparison to the raw data of the Danube River. The results of the other indices did not introduce representative outcomes of the raw data of the river. It was observed that some of these indices were biased and others have an eclipsing problem. However, these indices may be applicable to other water bodies.
IOP Conf. Series: Materials Science and Engineering, 2019
The assessment of the quality of tap water is very important to explore its fit for drinking, esp... more The assessment of the quality of tap water is very important to explore its fit for drinking, especially for developing countries. In the present paper, tap water quality evaluation has been carried out in the Balad city, Salah Al-Din Governorate, Iraq. A total of 17 tap water samples were collected from the city and analysed for various physicochemical and biological parameters, namely, pH, total dissolved solids (TDS), electrical conductivity (EC), turbidity, total hardness (TH), calcium magnesium, chloride and total coliform (TC). Suitability of water for drinking was evaluated based on the World Health Organization (WHO) and Iraqi standards. Spot maps were also generated using GIS to identify the spatial distribution of tap water quality parameters. The results revealed that the tap water is fit for drinking purpose regarding bacteriological pollution. Physicochemical parameters concentration of water samples were within standards except for turbidity. This parameter was highly exceeding the limits (5 NTU) in all tap water samples. Generally, tap water in the Balad city may pose risks to the health of people using it for drinking purposes. Moreover, cluster analysis revealed that the distribution system might affect the quality of tap water in the study area.
The assessment of hydrochemical quality of groundwater is very important to explore its nature an... more The assessment of hydrochemical quality of groundwater is very important to explore its nature and usefulness. In this paper, groundwater quality evaluation is carried out in the Balad district, Salah Al-Din Governorate, Iraq. A total of 28 groundwater samples are collected from shallow tube wells and analyzed for various physicochemical parameters. Groundwater suitability for drinking is evaluated based on the World Health Organization (WHO) and Iraqi standards, and suitability of groundwater for irrigation is assessed based on various hydrochemical parameters. The results reveal that the dominant types of groundwater based on piper diagram are mixed CaMgCl and CaCl. Gibbs ratio indicates that the groundwater in the studied area is affected by the evaporation process. The cation-anion exchange reaction in the studied area demonstrates that 54% of the groundwater samples indicate a direct base (cation-anion) exchange reaction, while 46% of the groundwater samples indicating the chloro-alkaline disequilibrium. Furthermore, generally all of the groundwater samples are unsuitable for drinking and irrigation. Cluster analysis reveals two different groups of similarities between the groundwater samples, reflecting different pollution levels in the studied area.
The present work suggests a simple approach for simulating the dispersion of pollutants in rivers... more The present work suggests a simple approach for simulating the dispersion of pollutants in rivers and streams with the aid of computational fluid dynamics technique. The two-dimensional advection–dispersion equation was solved using FlexPDE code to predict the biochemical oxygen demand (BOD) and the total dissolved solids (TDS) concentrations at the confluence of Diyala with Tigris Rivers. In this model, two sets of data were used for calibration and validation processes. Various values of longitudinal and transverse dispersion coefficients were adopted in the model to determine the suitable value using the trial-and-error method. The results revealed that the best agreement between simulated and measured values was observed when the longitudinal and transverse dispersion coefficients are close to 10 and 5 m 2 /s, respectively. The results showed that the proposed methodology is more suitable for TDS, while for BOD, it needs an accurate representation of the chemical or biological transformations. Keywords Pollutant transport · Diyala River · Tigris River · Water quality · FlexPDE
An attempt has been made to study the effects of the Jidostita tributary as point source pollutio... more An attempt has been made to study the effects of the Jidostita tributary as point source pollution on the Biochemical oxygen demand concentration in the Danube River, Romania. A numerical solution was introduced and solved using FlexPDE software. In this paper, three different scenarios of dispersion of BOD along the Danube River were examined by setting different values of river velocity. The temporal variations in simulation of BOD concentration were insignificant in this study and only spatial variations were considered. The results revealed that the BOD concentration at Gura Văii is about 3.4 mg/L in the first case, whereas, the BOD concentration at Gura Văii is about 3 mg/L in the second case and the BOD concentration at Gura Văii is about 2.5 mg/L in the third case. The BOD concentrations were dispersed to less than 0.5 mg/L at Schela Cladovei station in all cases (scenarios). The result of the simulated BOD concentration along the river was in agreement with observed BOD concentration. Therefore, FlexPDE solver can be used as a useful tool for predicting pollution dispersion and provide a good basis for future river water quality policy options for limiting of the pollutant sources.
Multivariate statistical methods such as factor analysis (FA) and cluster analysis (CA) were appl... more Multivariate statistical methods such as factor analysis (FA) and cluster analysis (CA) were applied to identify the main factors and pollution sources affecting on the water quality of Danube River and to evaluate spatial and temporal similarities or dissimilarities among the sampling sites and monitoring periods. Water quality of 14 parameters has been considered in four sampling stations during 1 year period. The results of factor analysis specified three factors representing 64.369% of the total variance in water quality. The main differences are related to domestic wastewater, industrial discharge, and agriculture activities from agricultural area. Hierarchical spatial CA revealed two different groups of similarities between the sampling sites, reflecting different pollution levels in the river water quality. Hierarchical temporal CA showed that the temporal variations in the river water are not relying on the local climate.
The main aim of the study was to explore the applicability of the one-dimensional (1D) steady sta... more The main aim of the study was to explore the applicability of the one-dimensional (1D) steady state model (QUAL2K) for simulating the water quality in large river. Danube River at lower Danube course was chosen as a case study. The model was calibrated using data on April, 2008 (spring season). Validation of the model was performed using data on September, 2008 (autumn season). Moreover, four different scenarios were examined to control the level of CBOD and DO in the river. The model output revealed that the calibration and validation results were in agreement with the observed values, with some exceptions. Although QUAL2K is one-dimensional steady state model, the simulated results were compatible with previous technical reports. Thus, it can be used as a suitable tool for simulating the water quality in large rivers.
Iraq's agricultural sector suffers from the salinity problem of agricultural land which reflects ... more Iraq's agricultural sector suffers from the salinity problem of agricultural land which reflects negatively on the production of field crops and agricultural land investment, particularly in the governorates geographically located in the sedimentary plain. The management of salinity problems facing by the agricultural sector has become crucial priorities for the Iraqi government. In this study, SWOT analysis was applied to suggest proper strategies that might be followed to solve the problem of salinity. After the internal and external factors have been identified, 17 strategies planning was developed. Internal–External Matrix (IE matrix) was used to select the appropriate type of strategy. Based on the results of Internal–External Matrix, government should consider the conservative strategies. Quantitative Strategic Planning Matrix (QSPM) was also used in this study. By applying the QSPM, re-arrangement of the proposed strategies has been made by importance and priority. The first three suggested strategies in term of importance and priority were establishment of the National Center for Agricultural Policy, investing in improved irrigation systems such sprinkler and drip irrigation and innovative agricultural technologies to control salinity are urgent.
ABSTRACT
An attempt has been made to assess the overall groundwater quality and identify major va... more ABSTRACT An attempt has been made to assess the overall groundwater quality and identify major variables affecting the groundwater quality in the urban area of Baghdad, Iraq. Groundwater samples from tube wells of 66 sampling sites were analyzed for the major physicochemical variables during May 2010. From the Hill–Piper trilinear diagram, it is observed that the majority of ground water from sampling sites are Ca -Mg -Cl- SO4 type and Na -K -Cl -SO4 type water. Multivariate statistical techniques such as factor analysis and cluster analysis were applied to identify the major factors (variables) corresponding to the different source of variation in groundwater quality of Baghdad. Factor analysis identified three major factor explaining 82.506% of the total variance in water quality; and the major variations are related to degree of mineralization of the geological components of soils, irrigation return flow, agricultural activities and mixing of wastewater. Hierarchical cluster analysis revealed three different groups of similarities between the sampling sites, reflecting different physico-chemical properties and pollution levels in the groundwater quality.
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Papers by Alhassan H Ismail
An attempt has been made to assess the overall groundwater quality and identify major variables affecting the groundwater quality in the urban area of Baghdad, Iraq. Groundwater samples from tube wells of 66 sampling sites were analyzed for the major physicochemical variables during May 2010. From the Hill–Piper trilinear diagram, it is observed that the majority of ground water from sampling sites are Ca -Mg -Cl- SO4 type and Na -K -Cl -SO4 type water. Multivariate statistical techniques such as factor analysis and cluster analysis were applied to identify the major factors (variables) corresponding to the different source of variation in groundwater quality of Baghdad. Factor analysis identified three major factor explaining 82.506% of the total variance in water quality; and the major variations are related to degree of mineralization of the geological components of soils, irrigation return flow, agricultural activities and mixing of wastewater. Hierarchical cluster analysis revealed three different groups of similarities between the sampling sites, reflecting different physico-chemical properties and pollution levels in the groundwater quality.
An attempt has been made to assess the overall groundwater quality and identify major variables affecting the groundwater quality in the urban area of Baghdad, Iraq. Groundwater samples from tube wells of 66 sampling sites were analyzed for the major physicochemical variables during May 2010. From the Hill–Piper trilinear diagram, it is observed that the majority of ground water from sampling sites are Ca -Mg -Cl- SO4 type and Na -K -Cl -SO4 type water. Multivariate statistical techniques such as factor analysis and cluster analysis were applied to identify the major factors (variables) corresponding to the different source of variation in groundwater quality of Baghdad. Factor analysis identified three major factor explaining 82.506% of the total variance in water quality; and the major variations are related to degree of mineralization of the geological components of soils, irrigation return flow, agricultural activities and mixing of wastewater. Hierarchical cluster analysis revealed three different groups of similarities between the sampling sites, reflecting different physico-chemical properties and pollution levels in the groundwater quality.