Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

Accepted Manuscript Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

Fathy Abdalla, Ramadan Khalil PII:

S1464-343X(18)30048-7

DOI:

10.1016/j.jafrearsci.2018.02.016

Reference:

AES 3148

To appear in:

Journal of African Earth Sciences

Received Date:

21 December 2016

Revised Date:

20 February 2018

Accepted Date:

21 February 2018

Please cite this article as: Fathy Abdalla, Ramadan Khalil, Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt, Journal of African Earth Sciences (2018), doi: 10.1016/j.jafrearsci.2018.02.016

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT 1

Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

Fathy Abdallaa,b*, Ramadan Khalilc aDeanship bGeology

of Scientific Research, King Saud University, Riyadh, Saudi Arabia

Department, Faculty of Science, South Valley University, Egypt

c Environmental

Affairs Office, Luxor, Egypt

*Corresponding

author. [email protected]

ABSTRACT The potential effects of anthropogenic activities, in particular, unsafe sewage disposal practices, on shallow groundwater in an unconfined aquifer and on surface water were evaluated within an urban area by the use of hydrogeological, hydrochemical, and bacteriological analyses. Physico-chemical and bacteriological data was obtained from forty-five sampling points based on33 groundwater samples from variable depths and 12 surface water samples. The pollution sources are related to raw sewage and wastewater discharges, agricultural runoff, and wastewater from the nearby Paper Factory. Out of the 33 groundwater samples studied, 17 had significant concentrations of NO3-, Cl- and SO42-, and high bacteria counts. Most of the water samples from the wells contained high Fe, Mn, Pb, Zn, Cd, and Cr. The majority of surface water samples presented high NO3- concentrations and high bacteria counts. A scatter plot of HCO3- versus Ca indicates that 58 % of the surface water samples fall within the extreme contamination zone, while the others are within the mixing zone; whereas 94 % of groundwater samples showed evidence of mixing between groundwater and wastewater. The bacteriological assessment

ACCEPTED MANUSCRIPT 2

showed that all measured surface and groundwater samples contained Escherichia coli and total coliform bacteria. A risk map delineated four classes of contamination, namely, those sampling points with high (39.3 %), moderate (36.3 %), low (13.3 %), and very low (11.1 %) levels of contamination. Most of the highest pollution points were in the middle part of the urban area, which suffers from unmanaged sewage and industrial effluents. Overall, the results demonstrate that surface and groundwater in Qus City are at high risk of contamination by wastewater since the water table is shallow and there is a lack of a formal sanitation network infrastructure. The product risk map is a useful tool for prioritizing zones that require immediate mitigation and monitoring.

Keywords: Sewage disposal, groundwater, contamination, hydrochemistry, bacteriological analysis, Qus City

1. INTRODUCTION Hydrogeological and hydrogeochemical characteristics of groundwater can be adversely affected by various anthropogenic activities such as urbanization, industry, and agriculture (Jeong, 2001; Foppen, 2002; Powell et al., 2003; Ellis and Rivett, 2007). In particular, human activities such as the installation of sewer systems can disturb groundwater levels in shallow aquifers that are highly vulnerable to contamination by causing a significant drop of the water level at the local scale due to the abstraction of large quantities of groundwater. Consequently, water laden with pollutants from raw sewage disposal flows toward the low-lying parts of a city, and this situation may be exacerbated after pumping is stopped, which will cause a further rise in the groundwater level. Deterioration in both the quantity and quality of groundwater represents a potential threat to urban communities. In Egypt, domestic wastewater is estimated to be between

ACCEPTED MANUSCRIPT 3

5.5 and 6.5 billion m3 (BCM)/yr, but only 2.97 BCM is subject to treatment processes. Out of this treated portion, about 0.7 BCM/yr is reused for agriculture purposes, of which 0.44 BCM undergoes primary treatment and the rest (0.26 BCM) is subjected to secondary treatment (Abdel-Shafy and Abdel-Sabour, 2006).

In the study area, the sewage network to collect and treat sewage is under construction, and therefore, sewage is currently disposed of and collected in underground sewage rooms, which have been constructed to be in direct contact with groundwater. No isolating surfaces or lined beds are present to prevent the sewage water and other contaminants from reaching and mixing with groundwater. In some areas of the city, sewage is discharged directly over the ground or into canals and drains (Fig. 1). As sewage water infiltrates into the shallow aquifer, pathogenic organisms such as bacteria and viruses can easily move within the aquifer and contaminate the groundwater. In the study area, wastewater discharges include domestic raw sewage, agricultural waste, and industrial effluents.

Figure 1. Location map of the study area.

Raw sewage is a potential source of various contaminants including pathogenic microbes, nutrients, toxic metals, and organic compounds (Gardner, 1997; Geriesh et al., 2004; USEPA, 2004), which can migrate downward directly to the groundwater. The human faecal material is comprised of a significant portion (~25%) of bacteria and contains approximately 3×107 coliform bacteria/100 mL; these microbes are diverse with respect to their ability to travel through the soil matrix (DeBorde et al., 1998). Microorganisms including faecal coliform bacteria (e.g.,

ACCEPTED MANUSCRIPT 4

Escherichia coli) and total coliform bacteria, as pathogenic indicator species, do not necessarily themselves cause disease, but they signal that the water is contaminated with disease-causing pathogens (Macler and Merkel, 2000; APHA, 2012). Total coliform counts in contaminated water are usually 10-times higher than faecal coliform counts. The threat to public health due to the transmission of pathogenic bacteria from sewage systems to groundwater has been reported worldwide. Many diseases may be caused by bacteria, such as diarrhoea, dysentery, cholera, and typhoid fever (DeBorde et al., 1998; Powell et al., 2003; Lerner and Harris, 2009). To avoid or minimize the adverse impacts of bacteriological contamination, groundwater production wells must be placed at a safe distance from contamination sources (Table 1); this distance depends upon the hydraulic properties of the soil type, such as hydraulic conductivity and infiltration rate.

Table 1. Table showing the recommended minimum distance between a groundwater well and source of contamination (Raghunath, 1987).

Besides geogenic sources, various anthropogenic sources including domestic sewage, agricultural runoff, and industrial effluents contain a complex mixture of inorganic compounds that are potentially harmful to groundwater quality in the area. These sources may include nitrate (NO3-) and potentially toxic heavy metals such as Pb, Cd, Zn, Fe, Mn and Cr in high concentrations. Typical sources of nitrate in groundwater are mainly related to agricultural and domestic wastewater discharges (Andersen and Kristiansen, 1983; Liu et al., 2005). Bacterial decomposition of organic matter present in sewage and animal waste is a common source of nitrate to water. Nitrate contents above the World Health Organization (WHO) guidelines may

ACCEPTED MANUSCRIPT 5

cause health problems for infants, as nitrate interferes with the blood’s ability to transport oxygen and causes oxygen deficiencies, which may lead to methemoglobinemia. Trace elements in groundwater are typically present in small quantities (˂1 mg/L). According to the carcinogenic classifications of heavy metals in drinking water by the International Agency for Research on Cancer (IARC, 2012), Cd, Cr, and Pb are classified as carcinogenic substances, while Zn, Fe, and Mn are classified as non-carcinogenic. Additional health impacts of heavy metals in drinking water have been reported by the U.S. Environmental Protection Agency (USEPA, 1994) and WHO (WHO, 2008). Furthermore, various organic compounds may be found in household discharges, including grease, detergent wastes, cleaning solvents, oil, and pharmaceutical drugs. The presence of clay–silt and fill deposit layers covering an aquifer may provide some protection because of their strong adsorption ability (Gu et al., 2010). Unfortunately, contamination risks for shallow aquifers are expected to be high. In the study area, the subsurface infiltration of a considerable amount of raw sewage water into the ground has resulted in waterlogged areas and groundwater pollution. An assessment of the hydrochemical and bacteriological characteristics of the surface and groundwater resources was carried out to examine the adverse impacts of wastewater disposal in the area. Our objective here was to investigate the interaction of wastewater with surface and shallow groundwater resources in the study area and to identify potential contamination from anthropogenic sources. This was achieved by quantifying the different types of pollutants and surveying the possible sources of contamination, which included discharges of raw sewage, irrigation return flows, and effluents from the Paper Factory.

2. GEOLOGY AND HYDROGEOLOGY OF THE STUDY AREA

ACCEPTED MANUSCRIPT 6

The study area lies in the southern part of Upper Egypt along the Nile between Qena and Luxor (Fig. 1); between latitudes of 25°50ʹ and 25º 57ʹ N and longitudes of 32°45ʹ and 32°48ʹ E. The area is site to many human-related activities, where the principal land use is a mixture of residential and agricultural uses. The region is characterized by cultivated land of the Nile floodplain ranging in elevation between 70.5 and 79.6 m (mamsl (meters above mean sea level) (Abdalla et al., 2009). The study area is located in the arid zone, which is characterized by arid and hot weather conditions. The temperature varies from 23 °C in winter to 44 °C in summer. Rainfall is very rare and not significant throughout the year; however, random flash showers sometimes occur during winter. The mean annual value of rainfall is ˂5 mm/yr, while the evapotranspiration rate is 185 cm/yr. The geological sequences in the study area include sedimentary rocks belonging to the Upper Cretaceous, the Tertiary, and the Quaternary. The Tertiary and Quaternary deposits overly Precambrian basement rocks (Fig. 2). According to Said (1981) and Omran et al. (2001), the oldest exposed sedimentary rocks are of Eocene age and composed of low-fissured limestone with clay and/or silt intercalations (Thebes Formation). The Pliocene deposits formed as a result of aggradations and degradations of Nile Valley material (Ezz El Deen et al., 2014). The upper part of the Paleocene deposits is known as the Dakhla Formation, and Tarawan Chalk, they composed of shale and marl is present where the lower part is composed of Esna Shale. The Upper Cretaceous deposits include the Duwi Formation (phosphates) and the Dakhla Formation (sand, shale, marl, and limestone) (Ezz El Deen et al., 2014), while the recent Nile deposits of Quaternary age are composed from Pleistocene (sand and gravel) and Holocene sediments (silty clay).

ACCEPTED MANUSCRIPT 7

Figure 2. Geological map of the study area (after EGSMA, 2002).

2.1. Surface water -Nile River system The Nile River along with the two main irrigation canals namely El-Kalabia and El-Gamalia and several other small irrigation canals and drains represent the surface water system in the Qus area (Fig. 1) .The Nile borders Qus City on the western side, and water is used directly and indirectly (via irrigation canals) for irrigation. The width of the valley in the study area is about 20 km, and the Nile River is 750 m at its widest point. At the High Dam area, the maximum water level of the Nile is 169 m (amsl) in August, and the minimum water level is 163 m (amsl) in July. In the study area, the maximum water level of the Nile is 72 m (amsl) in July, and the minimum water level is 66 m (amsl) in January (personal communication, Qena Irrigation Administration, 2010). These water level values are lower than the groundwater table in the surrounding Quaternary aquifer (Table 2).

Table 2. Physiochemical parameters of surface and groundwater, WT=water table, Na = not measured, very shallow wells in bold.

2.2. Irrigation canals There are two main canals crossing Qus City (Fig. 1): the El-Kalabia and the El-Gamalia. The El-Kalabia canal extends for about 270 km from the Esna barrages to the north of Nag Hammadi, and passes northward on the eastern side of the city. The maximum water level in the El-Kalabia canal in the upstream southern portion at Esna is 71.8 m (amsl) in July, while the minimum water level is 66 m (amsl) in January. The El-Gamalia canal lies on the western side of

ACCEPTED MANUSCRIPT 8

the city and is about 9 km in length. It starts from El-Sabah-Euon (southwestern part of the city) and passes through several villages in the city; and terminates at EL-Shaikhia in Qift City. Also, there are two small canals namely Qus and El-Maara that cross on the southwestern parts of the city (Fig. 1). The EL-Maara canal begins at the entrance of Qus City in Higgaza and ends in Abbasa village. The Qus canal is about 6 km in length, and starts in El-Kharanka village and ends in Abbasa village. Large quantities of wastewater and solid wastes are discharged directly into the two canals and transported indirectly to the groundwater. 2.3. Agricultural drains The Qus drain is the main drain serving the irrigated land in the study area (Fig. 1). The drain water is reused for irrigation either directly or indirectly via discharges into the Nile and/or the main canals. The reuse of drainage water for irrigation reduces the amount of fresh water required for crops.

2.4. Surface runoff Runoff represents the rainfall water that passes through the drainage basins when the rainfall intensity exceeds the infiltration capacity and leads to destructive flash floods. A significant runoff event occurred in November 1994, and the water caused extensive damage to the houses and other infrastructure (e.g., roads, houses and water reticulation pipes) in Higgaza village.

2.5 Groundwater system (Quaternary aquifer) Groundwater occurs under unconfined conditions in two shallow and hydraulically connected layers, which consist of a highly permeable and porous Pleistocene layer (gravels and various graded sand) on the bottom and a semi-permeable Holocene layer (clay–silt and/or fill deposits)

ACCEPTED MANUSCRIPT 9

on the top. The aquifer is underlain by Pliocene clays, which form an impervious base. The thickness of this aquifer, as well as its width, differs from one locality to another; for example, its thickness decreases from 300 m at Sohag to a few tens of meters in the southwestern part of Luxor (Sayed, 2004). The Holocene layer has low horizontal and vertical permeability, and it is a local and moderately to the low productive aquifer. The aquifer is very thick near the river channel and vanishing near the fringes of the valley; the thickness varies from 5 to 26 m (Abu El Elaa, 1990; Abdalla et al., 2009). Its horizontal and vertical permeability range from 0.40 to 1.00 m/d, and the vertical hydraulic conductivity is low and increases with depth (Abd El-Moneim, 1988). The Pleistocene layer forms the main aquifer and has high horizontal and vertical permeability. It is a high to moderate productive aquifer that situated along the course of the Nile River. Its hydraulic conductivity varies from 60 to 100 m/d, and the transmissivity ranges from 2000 to 6000 m2/d (Attia, 1985). The values of aquifer storativity amount to 5 to 50 × 10-4 for the semi-confined aquifer and 0.1 to 0.2 for the unconfined one. The upper semi-permeable clay–silt and/or fill deposit layer drains to the lower layer. According to earlier work (Barber and Carr, 1981; Farrag, 1982; Abd El-Moneim, 1988; Ahmed, 2003), infiltration test results showed that there was an infiltration rate of 2.5 m/d on average, which is indicative of good hydraulic connectivity between these two layers. The groundwater generally flows toward the north, and other local flow directions can be found either from or toward the Nile River, which acts as a major natural drain. Potential contamination from surface activities, especially discharged wastewater, is expected to affect the aquifer through vertical infiltration. Severely polluted surface waters artificially recharge the Quaternary aquifer in the study area. The recharge components consist of (1) seepage from irrigation canals along with infiltration of the irrigation-return flows where the city is surrounded by an agricultural belt of

ACCEPTED MANUSCRIPT 10

sugarcane fields; (2) domestic and industrial wastewater infiltration; (3) seepage from the broken-down drinking water supply network; and (4) upward leakage from the deep aquifers through fractures in the rocks. The recharge from irrigation was determined to be 0.8–1.1 mm/d over the clay (semi-confined) and 1.9–2.1 mm/d over the unconfined areas (Warner et al., 1991). Direct groundwater pumping from wells, especially for irrigations purposes, takes place in the new reclamation area, and water is ultimately discharged to the Nile; additionally, upward capillary flow occurs from the shallow water table owing to evapotranspiration. These are the main discharge components from the aquifer.

3. MATERIALS AND METHODS 3.1. Sampling and analytical procedures A total of 12 surface water samples were collected from irrigation canals and drains crossing the city as well as the Paper Factory Lake (samples 34 and 35 were from the El-Maara canal, samples 36 and 37 were from the Qus drain, samples 38, 39, 40, 41, and 42 were from the Qus canal, sample 43 was from the Paper Factory Lake, and samples 44 and 45 were from the ElGamalia canal); additionally, 33 groundwater samples were collected (24 samples were from very shallow wells 1–3.5 m in depth (Table 2, bold lines), and 9 samples were from shallow wells 8–12 m in depth). Both the residential area and the surrounding cultivated land were sampled to obtain data for the physicochemical analyses. The bacteriological analysis was carried out for 23 selected water samples (17 groundwater and 6 surface water samples). Sample bottles were cleaned, dried, and washed again before taking the sample with the sample water. All water samples were sealed carefully and labelled after collection. The samples were put into an ice box and then delivered to a refrigerator where they were stored at 4°C until being sent out

ACCEPTED MANUSCRIPT 11

to laboratories for the analysis. Samples for heavy metals measurements were acidified by nitric acid and kept in the refrigerator until analysis, and samples for nitrate measurements were acidified by sulfuric acid and delivered to a laboratory for analysis. Salinity, total dissolved solids (TDS), temperature (T), pH, redox potential (ORP), alkalinity, and electric conductivity (EC) were directly measured in the field. Major ions, trace inorganics, silica, and bacteriological analyses (E. coli and total coliform bacteria) for surface and groundwater samples were undertaken at the Laboratory of the Egyptian Environmental Affairs Agency at Aswan. Methods for the collection and analysis of water samples essentially followed those given by the American Public Health Association (APHA) (APHA, 2012), and to evaluate the validity of the analytical data, field blanks and field duplicates were incorporated. The chemical analyses for the major cations (Ca2+, Mg2+, Na+, K+) were performed by using a Spectra-AA-55 Atomic Absorption Spectrophotometer. The titration method was used for determinations of the anions HCO3- and Cl-. A DR/2400 Spectrophotometer was used for the determination of SO42-, NO3-, trace elements (Pb, Cd, Zn, Fe, Mn, Cr), and silica (SiO2).

3.2. Microbiological analysis Surface and groundwater samples for microbiological analysis were collected separately from 23 locations (17 groundwater and 8 surface water samples) (Table 3) in sterile 500-mL polyethylene containers. Collected samples were brought to the laboratory on ice, and the analysis was conducted within 24 h. Sterilized syringes were carefully used for water sampling to avoid contamination. The water was first pumped for 5 min, and then, sample containers were filled with the sterilized syringes. The containers were immediately capped with stoppers, and aseptic techniques were used during sampling. The samples were kept cool and delivered

ACCEPTED MANUSCRIPT 12

immediately to the laboratory. The total coliform test is a primary indicator of potable water suitable for drinking purposes. It estimates the numbers of faecal coliforms (E. coli) and other types of bacteria in 100 mL of water and is expressed in colony forming units (CFU)/100 mL of water.

4. RESULTS AND DISCUSSION 4.1. Contamination sources To investigate water contamination in the study area, all sources of domestic wastewater (raw sewage), agriculture pollutants, and industrial pollutants were studied (Fig. 3). Many different contamination sources were observed within the study area, and most consisted of municipal wastewater (sewage discharges; Fig. 3A). There was evidence of both point and non-point pollution sources in the study area. The point sources were fairly easy to recognize because the wastewater was discharged above ground and then was allowed to seep into nearby surface waters.

Figure 3. Field photographs showing various types of wastewater effluents: (A) sewage discharge (green colour refers to algae cover), (B) surface water (Qus canal) contamination, (C) Paper Factory Lake, (D) sugarcane factory wastewater discharge into the Nile.

4.1.1. Domestic sources As a high-density residential area with no sewer access, people in the study area construct pit latrines (single-chamber) built of red brickwork in their homes; thus, the main contamination source was on-site sewage discharge processes. These latrines are constructed in such a way that

ACCEPTED MANUSCRIPT 13

wastewater is allowed to percolate from the bottoms and walls, and higher permeability soils suggests that more percolation will take place, thus resulting in high rates of loading of toxic constituents and bacteria to groundwater. The amount of wastewater discharged depends on the total amount of domestic water consumption and the population density of the city. In the study area, the total domestic water consumption amounted to 25,000 m³/d. Qus’s drinking water network receives most of its water from the Nile River, which is the main source for the water supply, and there are also two municipal well facilities (the El-Maara and ElMaseed deep wells). Other deep wells are installed in many places in the study area in the areas that are not serviced by the water network. Qus’s drinking water network has old pipes that are ˃20 years old. It was poorly designed, and daily interruptions and losses of water occur; breaks in the pipes increase the probability of water contamination. The majority of this water is artificially recharged into the ground as sewage-laden with pollutants, and such discharges cause waterlogging and groundwater and surface water contamination. As a result of rising groundwater levels, the pit latrines can become filled with sewage water, and at times, raw sewage has poured out into the streets (Fig. 3A). Wastewater is also transported by vehicles in large quantities to nearby irrigation canals (e.g., the El-Gamalia, El-Maara, and Qus canals) and drains. Sometimes it is moved to the neighbouring cultivated areas without any control from the City Council (about 150,000 people live around these canals, and the majority of them discharge their raw sewage directly into them). The most affected parts are confined to the city centre, especially in Ewadate, Shaareen, and El-Fashawna areas (Fig. 3A), and some scattered points of impact can also be found in the western parts around the Paper Factory Lake. This was confirmed from the results of the chemical and bacteriological analyses, where the main pollutants detected in sewage wastewater contained organic material (microbial pathogens),

ACCEPTED MANUSCRIPT 14

nitrogen-based compounds, and trace elements, all of which may negatively impact human health.

4.1.2. Agricultural sources The city is surrounding by agriculture, and intense yearlong agricultural practices take place, especially in the sugarcane fields that are located in close vicinity to the houses. Excessive use of artificial fertilizers along with flash irrigation techniques (two to three times a month) result in non-point sources of contamination from irrigation-return flows. Improper usage of agrochemicals, fertilizers, and manure in agricultural areas is the main source of nitrate contamination. Commonly used fertilizers include urea, calcium nitrate, ammonium nitrate, ammonium sulfate, and superphosphate. The major types of pollutants that can be expected in agricultural drains are salts, nutrients (nitrogen and phosphorus), pesticide residues, pathogens, toxic inorganic compounds, and organic compounds; their adverse impacts on groundwater may accumulate over time. The presence of nitrate above the permissible level set by the WHO and the Egyptian Higher Committee for Water (EHCW) may be due to the high use of fertilisers in neighboring agricultural fields and/or from seepage from the on-site sewage discharge processes.

4.1.3. Industrial sources There is not much industrial activity in the study area, and the main sources of industrial pollution are the Paper Factory and Sugar Factory (Figs. 3C and D), located in the northwest part of the study area. These factories discharge their effluents following little to no treatment into the Nile or to lakes. The main pollutants from the Sugar Factory include organic matter high in carbohydrates; those from the Paper Factory include bagasse, oils, and grease. The discharged

ACCEPTED MANUSCRIPT 15

wastewater from the Paper Factory has a high chemical oxygen demand (COD) and biochemical oxygen demand (BOD). The Paper Factory discharges liquid industrial wastes into a poorly protected lake (sample No. 43; Fig. 3C), which is situated close to the Nile. The chemical reactions among these pollutants generate a variety of toxic substances. The factory discharges approximately 20,000 m3/d of wastewater into the lake and the Nile. Various raw materials including bagasse are used for paper production, and these materials are treated physically and chemically to eliminate lignins and produce white paper. Industrial wastewater containing various pollutants may infiltrate underground and reach the groundwater causing severe contamination.

4.2. Groundwater level and flow Measurements of the water table depth within 33 groundwater wells have been carried out, and water levels were calculated. The water table varies from 63 to 75 m (amsl) in much of the study area (Table 2). The depth to water was ~1 m below the ground in the low-lying southeastern parts, and it increased in the western parts of the Nile River to ~12 m. The differences between the very shallow and shallow water table levels reflect the variation in the ground surfaces and the location of the sand bed below a sequence of alternating clay–silt and/or fill deposits. Based on the analysis of the water table, a gradual decrease in the northward and westward directions was noticed. Thus, the general groundwater flow direction was from the southeast to the northwest towards the Nile, with anomalies in some regions, especially in the city centre. As the groundwater level ranged from very shallow to shallow below the ground surface in some areas, waterlogging was observed when the amount of discharged wastewater exceeded the infiltration capacity of the top layer (clay–silt and/or fill deposits).

ACCEPTED MANUSCRIPT 16

4.3. Major hydrochemical parameters The most important physicochemical parameters including pH, EC, total hardness (TH), TDS, Cl-, SO42-, NO3-, Pb, Cd, Zn, Fe, Mn, Cr, and SiO2 were determined in surface and groundwater (Table 2) as pollution indicators. Areal geographic information system (GIS) distribution maps of these parameters were prepared by using ArcGIS software with the kriging interpolation method.

4.3.1. Temperature and pH (T and pH) As shown in Table 2, the groundwater temperature ranged from 15.6 to 26.9°C with an average of 23.1°C, while the surface water temperature ranged between 15.6 and 23°C with an average of 18.2°C. The pH values of groundwater samples ranged from 7.1 to 8.2 with an average of 7.6, and thus, the data were reflective of neutral to slightly alkaline conditions. The surface water pH values varied between 7.8 and 9.2 with an average of 8.3, which is indicative of mildly alkaline water. These pH values might have been due to the high content of base compounds such as calcium bicarbonate.

4.3.2. Redox potential (ORP) The redox value in groundwater ranged from 29 to 311 mV with an average of 113 mV. The high ORP values observed in very shallow wells are reflective of oxic conditions, and the lowest value was observed close to the city centre. In surface water, redox values varied between 43 to 302 mV with an average of 134.5 mV. The lowest value was observed in sample No. 39, which was collected close to the downstream part of the Qus canal. This value reflects reducing

ACCEPTED MANUSCRIPT 17

conditions due to discharges of raw sewage into the canal and the accumulation of algae. Under reducing conditions, nitrate undergoes denitrification, and this coincides with high iron and manganese contents (Table 2). The highest ORP value was observed in sample No. 41, which was collected close to the upstream part of the Qus canal and away from the city centre; this value reflects oxic conditions, and such conditions are present because of the continuous recharge from the Nile (Fig. 4).

4.3.3. Electrical conductivity (EC) In groundwater, EC and TDS values exceeded those of surface water because of water-rock interactions as well as the anthropogenic inputs. The EC of groundwater varied between 385 and 4620 µS/cm with an average of 1719 µS/cm. Some wells with high salinity values were located close to the city centre (Fig. 4). These were largely impacted by anthropogenic sources, primarily by domestic and industrial wastewater effluents. For surface water, the EC values ranged from 272 to 2311 µS/cm with an average of 751 µS/cm; these values were lower than the mean values in groundwater. The Paper Factory Lake (sample No. 43; Fig. 4) had a high EC value of 2311 µS/cm because of the discharge of many industrial and chemical wastes into the lake. High ions contents in the water cause the water to be corrosive, and scale formation can occur.

4.3.4. Total hardness (TH) Total hardness of the collected samples was calculated based on Todd (1980), and the data were compared with ASTM (1976) classification levels. The predominant class (29 samples, 88%) of total hardness in groundwater samples was the very hard class (>200 mg/L), and the rest (4 samples, 12%) ranked at the moderately hard level (101–200 mg/L) (Fig. 4). The high values

ACCEPTED MANUSCRIPT 18

of total hardness may have been due to the dissolution of HCO3-, SO42, and the alkaline features of the soils. Out of the 12 surface water samples, 6 samples (50%) were classified into the very hard class, 5 samples (42%) were classified into the moderately hard class, and only 1 sample was classified into the slightly hard class (56–100 mg/L).

4.3.5. Chloride and sulfate (Cl- and SO42-) Except for in saline and brackish water, the contents of chloride in natural water (which are typically around 100 mg/L; Fetter, 1999) can be used as an indicator of anthropogenic contamination. The Cl- concentrations in groundwater varied from 21.0 to 192.7 mg/L with an average of 63 mg/L, and that of SO42- ranged from 6.3 to 557.5 mg/L with an average of 169 mg/L; thus, a wide range of variation was detected. In surface water, the Cl- content ranged from 19.6 to 72.9 mg/L with an average of 41.7 mg/L, while the SO42- content ranged from 13.2 to 479.5 mg/L with an average of 100.4 mg/L. The highest Cl- and SO42- contents in surface water were recorded in sample No. 43, Paper Factory Lake (Fig. 4). The measured Cl- contents were under the recommended limits of WHO (2008) and EHCW (2007) (250 mg/L), and only three groundwater samples and one surface water sample had SO42contents above the permissible limit of 400 mg/L. Higher values of Cl- and SO42- were recorded in the places where the dumping of sewage is common and where animal wastes and fertilisers containing KCl and potassium sulfates are present; the significant positive correlation between Cl and SO42- confirmed this proposition (Fig. 4). Additional chloride sources may have been due to the dissolution of halite from waterbearing formations. The increased concentrations of alkalis and chloride are indicative of the

ACCEPTED MANUSCRIPT 19

influence of mixing between natural water and wastewater leaking from the sewage ponds, latrines, and cesspits. The significant positive correlation between SO42- and Cl- implies that they both originated from conventional sources like human and animal wastes as well as fertilisers. Moreover, the SO42-/Cl- ratio in 55% of the water samples exceed unity, which might be an indicator of contamination by sewage water; these samples were mostly concentrated close to the city centre.

4.3.6. Nitrate (NO3-) Since nitrogenous materials are rare in the geological record, nitrate in groundwater is usually due to anthropogenic activity; clean natural water typically contains ˂10 mg/L nitrate. In the study area, the sources of nitrate included both diffuse and point sources. The nitrate distribution map (Fig. 4) shows that nitrate concentrations in groundwater varied between 5.17 (well No. 7) and 96.11 mg/L (well No. 23) with an average of 38.7 mg/L. The lowest values were detected in the northwestern and southwestern parts of the city, which might reflect that the inputs were mainly in the form of ammonium and not nitrate; these data coincided with low ORP values of 48 mV and higher Fe and Mn contents (Figs. 4 and 5). The highest values were detected in the middle and northwestern parts of the city. These areas are enclosed by closely spaced standing houses in the oldest and densely populated part of the city and agricultural lands (Fig. 4). The nitrate content of the surface water ranged from 26.1 (sample No. 44, El-Gamalia canal) to 97.4 mg/L (sample No. 39, Qus canal) with an average of 53.4 mg/L. The raw sewage discharged from the oldest and highly populated part (Fig. 4) was likely behind the high value recorded in the Qus canal. Of the 33 wells, 10 samples (30%), and of the 12 surface water samples, 6 samples (50%), exceeded the limit of 50 mg/L set for drinking water by the WHO and

ACCEPTED MANUSCRIPT 20

EHCW, but the samples were still under the allowable limit of 135 mg/L for irrigation water. The high nitrate values could be partly the result of organic sources (sewage wastewater and manure applications) and inorganic sources (improper use of nitrogenous fertilizers in the agricultural lands of poor quality).

Figure 4. GIS spatial distributions of SO42-, Cl-, NO3-, EC, ORP, and TH in the study area.

4.3.7. Trace elements Trace elements including Pb, Cd, Zn, Fe, Mn, and Cr were detected in surface and groundwater samples in the study area. The concentrations in some samples were at concentrations more than the allowable limit for drinking water and irrigation purposes according to the WHO (2008) and USEPA (1994) based on their toxicity and bio-accumulative nature (Fig. 5; Table 2). Lead contents in groundwater varied between 0.001 and 0.025 mg/L with an average of 0.01 mg/L. Lead values exceeded the maximum contaminant level for drinking water set by WHO (0.01 mg/L) in 40% of the samples, but the values were less than the standard for irrigation water (5 mg/L). For surface water, Pb contents were higher compared to that of the groundwater, and they varied between 0.003 and 0.18 mg/L with an average value of 0.011 mg/L. The highest value was observed in sample No. 43 from the Paper Factory Lake (Fig. 5; Table 2). Elevated Pb concentrations may reflect the seepage of wastewater and the leaching of fertilisers into the aquifer. Lead is toxic in small concentrations, and Pb can be especially harmful when it exceeds the recommended limit of 0.015 mg/L (WHO) in drinking water. Lead can cause anaemia, lethargy, and abdominal pain along with delays in physical or mental development for infants and children, and kidney problems and high blood pressure for adults

ACCEPTED MANUSCRIPT 21

(USEPA, 1994; WHO, 2008). Cadmium contents in groundwater varied from 0.001 to 0.015 mg/L with an average 0.005 mg/L, while those in surface water varied from 0.001 to 0.012 mg/L with an average of 0.006 mg/L. Rocks mined for phosphate fertilisers contain varying amounts of Cd. Cadmium is very toxic, and elevated concentrations may cause liver and kidney damage (0.003 mg/L; WHO, 2008). Zinc values in groundwater ranged from 0.002 to 1.25 mg/L with an average of 0.26 mg/L, and those in surface water ranged from 0.002 to 1.11 mg/L with an average of 0.422 mg/L. Zinc contents in most wells, as well as in the surface water samples, was high compared to the recommended values for drinking water and for irrigation purposes (2 mg/L). The highest Zn content was observed in sample No. 43, Paper Factory Lake, and this was due to the accumulation of the solid and industrial wastewater discharged (Fig. 5; Table 2). Zinc in drinking water does not readily cause ill effects, but it can impart a metallic taste to the water or a milky appearance at levels around 3 mg/L (WHO, 2008). Iron contents in groundwater varied from 0.012 to 0.284 mg/L with an average of 0.125 mg/L, while the values in surface water varied from 0.011 to 0.121 mg/L with an average of 0.044 mg/L. High Fe contents in water can stain laundry and contribute to clogged pipes and well openings (0.3 mg/L; USEPA, 1994). Manganese was less abundant in the groundwater than iron, and the Mn contents of the groundwater ranged from 0.001 to 0.283 mg/L with an average of 0.106 mg/L, while the values for surface water ranged from 0.001 to 0.091 mg/L with an average of 0.02 mg/L. Similarly, the high Mn contents might have been due to the sewage disposal practices, the use of pesticides on older croplands, and industrial wastewater discharges from the Paper Factory. As shown on Figure 5 the highest Fe and Mn contents were observed in the northwestern and eastern parts of the city. High Mn contents in water can cause a bitter metallic taste, and the water may be black to brown; Mn also leaves grey stains on porcelain and

ACCEPTED MANUSCRIPT 22

fabrics and contributes to clogged pipes and wells (0.5 mg/L; WHO, 2008). The presence of dissolved Fe and Mn in groundwater is mainly controlled by the availability of low ORP values (˂200 mV). Degradation of infiltrated organic wastes in surface and groundwater results in the depletion of the dissolved oxygen. The Fe-rich and Mn-rich reduced zones in this study coincided quite well with the relatively low nitrate and redox values, which was likely due to denitrification reactions (Table 2). Chromium sources in groundwater were likely from the sewage sludge and the use of organic fertilisers (manure) in agriculture areas (Deutsch, 1997). Chromium concentrations in groundwater samples varied between 0.001 and 0.082 mg/L with an average of 0.03 mg/L (Fig. 5; Table 2). In surface water, the Cr values ranged between 0.026 and 0.114 mg/L. High Cr contents above the WHO guideline (0.05 mg/L) were detected in well No. 14 and in surface water sample No. 43, Paper Factory Lake, which might have been due to the accumulation of the industrial wastewater discharged. One potential impact of high Cr levels is acute toxicity to plants and animals. Drinking water with high levels of Cr (0.05 mg/L) over long periods of time can lead to cancer, while lower doses may irritate the gastrointestinal mucus (Kaufman and Dinicola, 1970; WHO, 2008). According to the spatial distribution map (Fig. 5) for the detected heavy metals, except for Fe and Mn, the highest values were observed in the western and central parts of the city.

Figure 5. GIS spatial distributions of heavy metals Fe, Mn, Pb, Zn, Cd, and Cr in the study area.

The presence of trace elements with remarkable concentrations in surface and groundwater might be related to the disposal of wastewater, especially from industrial and sewage sources into the groundwater or the canals and drains.

ACCEPTED MANUSCRIPT 23

Silicon in natural water is usually present as silicon dioxide, SiO2, or its hydrated form, Si (OH) 4. As much as 60% of the Earth’s crust is composed of silicate minerals; therefore, silica constitutes the bulk of rocks, soils, clays, and sands (Khan et al., 2015). For groundwater, the average silica content is typically 17 mg/L, and for stream water, the content is typically about 14 mg/L. Dissolved silica in natural water is related to the weathering of silicate minerals. In groundwater samples, SiO2 contents ranged between 2.4 and 25 mg/L with an average of 14.9 mg/L. Surface water samples exhibited low silica contents in comparison to groundwater samples, and these samples ranged between 0.8 and 9.4 mg/L (the high concentration was for sample No. 43, Paper Factory Lake) with an average of 2.3 mg/L. The long-term water-rock interactions in the groundwater aquifer were behind the higher silica contents in groundwater compared to surface water, but the dilution effect by water flowing in canals and in drains likely played a key role.

4.4. Mixing of wastewater with groundwater Relationship of Ca with HCO3-: Unaffected groundwater is classified as a bicarbonate water type, with HCO3- concentrations varying from 7 to 11 meq/L and Ca concentrations varying from 9 to 16 meq/L. On the other hand, wastewater is carbonate-poor water with HCO3- and Ca contents ranging between 4–4.2 meq/L and 2.6–3 meq/L, respectively. These two water types are assumed to represent end-members of a mixed system (Domínguez-Mariani et al., 2004). Figure 6a shows that values of HCO3- and Ca in the wastewater samples were adversely affected by wastewater infiltration, as indicated by the by the random distribution of the water points that reflect different chemical compositions. The plot (Fig. 6a) suggests that the sampling points were

ACCEPTED MANUSCRIPT 24

located between surface wastewater and natural, unaffected groundwater values, thus defining a mixing trend.

Figure 6. Scatter plots of (a) HCO3- versus Ca and (b) SiO2 versus Cl- in the study area.

The severely contaminated zone (Fig. 6a) included seven surface water points from the ElMaara and Qus canals and two samples from the El-Gamalia canal, and the results strongly support the conclusion that direct raw sewage disposal influenced the water quality in these canals. Two very shallow groundwater wells (No. 5 and 7) were located in this zone, and here, wastewater predominantly influenced the groundwater. This shows that the interaction between wastewater and surface and groundwater plays a major role in the contamination process, mainly through wastewater infiltration. Thus, the major contributors of major ions, nitrates, heavy metals, and bacteria to surface and groundwater were from raw sewage disposal practices, agricultural runoff, and industrial activities. Relationship of SiO2 with and Cl-: Chloride acts as a reactive tracer and moves freely in groundwater as large-sized ions; specifically, it does not readily adsorb onto mineral surfaces nor enter rock-forming minerals, and it does not participate in ion exchange processes (Khan et al., 2015). Therefore, high chloride concentrations in groundwater can undoubtedly be used as valuable indicators of anthropogenic impacts. Meanwhile, SiO2 enters the groundwater mainly from water-rock interactions (Hem, 1985). Accordingly, SiO2 versus Cl- plots (see Fig. 6b) can be used to assess the contributions of anthropogenic and geogenic processes to the groundwater chemistry.

ACCEPTED MANUSCRIPT 25

In the plot of SiO2 versus Cl- (Fig. 6b), three distinguished groups were identified. Group (I) consisted of four very shallow groundwater wells where the water depth was ˂3.5 m, and this group had low SiO2 contents (˂4 mg/L) and high Cl- contents (up to 200 mg/L) reflective of anthropogenic contamination. Group (II) contained the majority of the samples with Cl- contents that progressively increased from 25 to 165 mg/L and almost constant SiO2 values (15 to 17 mg/L). This indicates that the bulk of the Cl- content was acquired by processes (anthropogenic) other than those responsible for the acquisition of SiO2 (geogenic). Group (III) contained four samples clusters, and the results exhibit comparatively high SiO2 contents (20–25 mg/L) together with low Cl- contents (˂50 mg/L), which suggests that the bulk of Cl- was acquired through geogenic processes (rock-water interactions) and not anthropogenic processes in these locations. SiO2–Cl- and HCO3–Ca data provided clear evidence that the role of water-rock interaction process was relatively less significant than anthropogenic processes in terms of the water chemistry in the study area.

4.5. Water bacteriological characteristics For the bacteriological analyses, total coliforms, faecal coliforms, Salmonella, Pseudomonas, and Klebsiella were examined at selected water points (Table 3). The presence of faecal coliform bacteria indicates that a faecal source was present, likely from the mixing of domestic wastewater, cesspools leaking, and/or sewage discharges into surface and groundwater. Such data indicate that pathogenic organisms may be present, which could be capable of causing diseases that represent severe and even deadly health concerns. Bacteriological examination in the forms of E. coli and total coliforms indicated that there was great variation in the spatial distribution of the coliform counts. The optimal pH values for bacterial growth are 6–8 (for

ACCEPTED MANUSCRIPT 26

neutrophilic bacteria), whereas extremely acidic or basic environments tend to prevent bacterial growth. In the study area, pH values of groundwater were 7.1–8.2 with an average of 7.6, and such pH values represent suitable environments for bacterial growth. Out of 17 shallow wells, 10 wells (59%) along with all the surface water points (100%) had significant counts of faecal coliforms, which are facultative aerobic organisms (Fig. 7; Table 3). The results showed that all surface and groundwater samples had total coliform levels that exceeded the recommended limit of 0 CFU/100 mL of sample (Table 3). Table 3. Results of the bacteriological analysis (count CFU/100 ml) of selected 17 groundwater and 8 surface water samples, SW (sewage water from El-Salhiya sewage treatment plant at Qena).

Figure 7. GIS spatial distributions of faecal coliform and total coliform in the study area.

In groundwater, the highest count of bacterial contamination was observed in well No. 12 (112 fecal and 270 total coliforms), which is where sewage and wastewater discharges with high organic matter content accumulate. The minimum count (0 faecal and 8 total coliforms) was observed in well No. 2. In surface water, the highest bacterial count (224 fecal and 965 total coliform) was observed in sample No. 38, which was collected close to the downstream part of the Qus canal and in the southern portion of the city center (Fig. 7). This may have been due to heavy discharges of raw sewage and algae accumulation. The lowest bacterial count (39 faecal and 78 total coliforms) was observed in sample No. 41, which was collected in the upstream part of the Qus canal; this may have been due to the continuous recharge from the Nile. Similar trends were observed for the ORP values (Tables 2 and 3). Accordingly, proper sanitary

ACCEPTED MANUSCRIPT 27

protections should be provided when production wells are constructed to reduce or minimize the impacts of bacteriological contamination. The presence of coliform bacteria indicates that the water may be contaminated with organisms that can cause disease. The faecal and total coliform counts in the sewage water of the El-Salhiya sewage treatment plant at Qena, north of Qus City, were 106,000 and 1,800,000 CFU/100 mL, respectively. According to the WHO guideline for drinking water, the total and faecal coliform count should be 0 CFU/100 mL, while no more than 200 faecal coliforms/100 mL of water should be present in areas where recreational activities take place. Water boiling and/or chlorination are common disinfection techniques for water contaminated with coliform bacteria. From the above results, only the water from the deep wells and the established network is recommended for drinking in the study area.

4.6. GIS-based risk map Surface water resources in the study area are highly impacted, as shown from the above discussions, and therefore, a contamination risk map was constructed for the groundwater samples to help protect potable water supplies. The risk map was based on six major water pollution indicators (NO3-, Pb, Cr, Cd, faecal coliform, and total coliform), and these data were integrated into the GIS along with land-use and possible contaminant source information. For each pollution indicator, a GIS thematic layer was created (Fig. 8) to extrapolate the areas with different risk classes (Fig. 9). Four different classes on the risk map were assumed based on the maximum allowable levels (MAL) set by the WHO and EHCW and the obtained values from the chemical and bacteriological analyses. For example, the nitrate content was classified into four risk classes as follows: class 1: ˃45 mg/L, high; class 2: 20–45 mg/L, moderate; class 3: 10–20 mg/L, low; and class 4: ˂10 mg/L, very low. In the case of faecal and total coliform, bacterial

ACCEPTED MANUSCRIPT 28

counts were divided into the following categories: ˃50 CFU/100 mL, high; 10–50 CFU/100 mL, moderate; 0–10 CFU/100 mL, low; and 0.0 CFU/100 mL, very low.

Figure 8. GIS thematic maps for NO3-, Pb, Cr, Cd, faecal coliform, and total coliform.

Areas of high contamination risk (39,3% of the area; these sites were located in the western, northeastern, and central parts) were detected in locations where intensive wastewater is discharged from various sources; thus, strict measures to prevent or minimize the groundwater contamination are urgently needed in these areas. Areas of moderate risk were also common (36.3%) along the northwestern, southern, and eastern parts of the study area. Low and very low risk zones amounted to only 13.3% and 11.1%, respectively, of the study area, and these few sites were mainly located in the southeastern part of the study area.

Figure 9. GIS risk map for the study area.

Based on the analysis of the risk map, a major portion of the study area is in high and moderate risk contamination zones, and only a smaller portion in the southeast can be classified as low and very low-risk zones. Accordingly, the aquifer is under stress from contamination, and the shallow water table and the absence of a formal sanitation network are exacerbating the problems in this region. The validity and accuracy of the resulting risk map was verified against available hydrogeological data, field observations, and the locations of existing sewage and wastewater infrastructure. This risk map should be a useful tool for prioritizing mitigation activities in the future.

ACCEPTED MANUSCRIPT 29

5. SUMMARY AND CONCLUSION Potential physicochemical and bacteriological hazards in a shallow unconfined aquifer and surface water were evaluated by screening 45 water samples. The detected threats in the study area arose mainly from anthropogenic activities, especially the leakage of sewage, irrigationreturn flows, and/or industrial wastewater discharges. The contents of nutrients, Cl-, SO42-, heavy metals, and bacterial loads in many samples were above the WHO and EHCW standards. Results showed that 52% of the examined groundwater samples had concentrations of NO3-, trace metals, Cl-, and SO42- that were higher than the recommended maximum permissible levels. Effluents from domestic and industrial wastewaters and irrigation-return flow laden with chemical fertilisers from nearby agricultural areas might be behind these high contents. As indicated by the HCO3- versus Ca plot, the majority of groundwater samples (94%) fell in the wastewater and groundwater mixing zone. Meanwhile, the remaining groundwater samples (6%) along with 58% of the surface water samples fell in the severely contaminated zone. The SiO2 versus Cl- plot revealed anthropogenic impacts in the form of mixing between wastewater and groundwater. Results showed that faecal coliforms are problematic in 59% of the groundwater samples and 100% of the surface water samples, and all samples contained total coliforms. The high bacterial loads confirm that the contamination is from the anthropogenic activities in the form of sewage effluents. Six major water pollution indicators (NO3-, Pb, Cr, Cd, faecal coliform, and total coliform) were used to create six thematic maps, which were processed into a risk map. According to the risk map, four main contamination zones (high, moderate, low, and very low) within the aquifer were identified. The majority of the study area (75.6%) was classified as “moderate” to “high” risk, and these locations occupied the western, northeastern,

ACCEPTED MANUSCRIPT 30

and central parts of the study area, which suffer from heavy sewage and industrial effluents. Low and very low-risk zones for aquifer contamination occupied only 24.4% of the study area along the northwestern and southeastern parts. The risk map was verified with hydrogeological, field, and laboratory data. As indicated above, the most impacted parts were at or near the city centre in areas that suffer from heavy sewage and industrial effluents. Results confirmed that, because of improper wastewater disposal practices, surface and groundwater resources are at a relatively high risk for contamination. Thus, future mitigation efforts will be needed to protect the water resources in this region.

ACKNOWLEDGMENTS We would like to acknowledge the Journal Editor and the anonymous reviewers for helpful advice and suggestions. The authors would like to extend their sincere appreciation to the Deanship of Scientific Research, King Saud University for its funding through Research group (RG-1437-012).

REFERENCES Abdalla, F., Ahmed, A., Omr, A., 2009. Degradation of groundwater quality of Quaternary aquifer at Qena, Egypt. Journal of Environmental Studies, 1: 19–32. Abd El-Moneim, A., 1988. Hydrogeological Conditions of the Nile Valley at Sohag Province. MSc. Thesis, Sohag Faculty of Science, Assiut University. Abdel-Shafy, H., Abdel-Sabour, F., 2006. Wastewater reuse for irrigation on the desert sandy soil of Egypt: Long-term effect. In: Hlavinek, P., et al. (Eds.), Integrated Urban Water Resources Management, Springer, The Netherlands, pp. 301–312.

ACCEPTED MANUSCRIPT 31

Abu El Elaa, E.M., 1990. Chemistry of the Nile water between Aswan and Assiut, Upper Egypt. Bull. Geol. Dept., Faculty of Science, Assiut University, vol. 19 (2-F), pp. 35–49. Ahmed, A.A., 2003. The Impact of Hydrogeological Conditions on the Archaeological Sites at Some Localities between Qena and Aswan, Egypt. PhD. Thesis, Sohag University, Egypt. American Public Health Association (APHA), 2012. Standard Methods for the Examination of Water and Wastewater, 22nd ed. APHA, American Water Works Association, Washington DC, 1496 pp. American Society for Testing and Materials (ASTM), 1976. Water and Environmental Technology. Annual Book of ASTM Standards, USA, Sec. 11, Vol. 11.01 and 11.02, West Conshohocken. Andersen, L., Kristiansen, H., 1983. Nitrate in groundwater and surface water related to land use in the Karup Basin. Denmark. Environmental Geology, 5 (4): 207–212. Attia, F., 1985. Management of Water System in Upper Egypt. PhD. Thesis, Faculty of Engineering, Cairo University. Barber, W., Carr, D.P., 1981. Water management capabilities of the alluvial aquifer system of the Nile Valley, Upper Egypt. Technical Report No. 11, Water Master Plan, Ministry of Irrigation. DeBorde, D.C., Woessner, W.W., Lauerman, B., Ball, P.N., 1998. Virus occurrence and transport in a school septic system and unconfined aquifer. Ground Water, 36 (5): 825–834. Deutsch, W.J., 1997. Groundwater Geochemistry: Fundamentals and Applications to Contamination. CRC Press, Boca Raton, Florida, 221 pp.

ACCEPTED MANUSCRIPT 32

Domínguez-Mariani, E., Carrillo-Chávez, A., Ortega, A., Orozco-Esquivel, M.T., 2004. Wastewater reuse in Valsequillo agricultural area, Mexico: Environmental impact on groundwater. Water, Air and Soil Pollution, 155: 251–267 Egyptian Higher Committee for Water (EHCW), 2007. Egyptian Standards for Drinking Water and Domestic Uses (in Arabic). Egyptian Geological Survey and Mining Authority (EGSMA), 2002. Geological map of Egypt, scale 1: 2,000,000. In: Annals of the Geological Survey of Egypt, vol. XXIV, 612 pp. Ellis, P.A., Rivett, M.O., 2007. Assessing the impact of VOC-contaminated groundwater on surface water at the city scale. Journal of Contaminant Hydrology, 91: 107–127. Ezz El Deen, M., El Sayed, A., Barseem, M., 2014. The impact of subsurface geological structure on the groundwater occurrence using geophysical techniques in wadi El Kallabiyyah and wadi As Sabil, East Esna, Eastern Desert, Egypt. Arabian Journal of Geosciences, 7 (6): 2151–2163. Farrag, A.A., 1982. Hydrogeological Studies on the Quaternary Water-bearing Sediments in the Area between Assiut and Aswan. MSc. Thesis, Assiut University, Egypt. Fetter, C.W., 1999. Contaminant Hydrogeology. Prentice-Hall, Englewood Cliffs, NJ. Foppen, J.W., 2002. Impact of high-strength wastewater infiltration on groundwater quality and drinking water supply: the case of Sana'a, Yemen. Journal of Hydrology, 263: 198–216. Gardner, B., 1997. Groundwater Contamination via Sewer Infiltration and Overflow. Groundwater Pollution Primer. CE 4594: Soil and Groundwater Pollution, Civil Engineering Dept., Virginia Tech.

ACCEPTED MANUSCRIPT 33

Geriesh, M., El-Rayes, A., Ghodeif, K., 2004. Potential sources of groundwater contamination in rafah environs, north Sinai, Egypt. Proc. 7th Conference of Geology of Sinai for Development Ismailia, pp. 41–52. Gu, X., Evans, L.J., Barabash, S.J., 2010. Modeling the adsorption of Cd (II), Cu (II), Ni (II), Pb (II) and Zn (II) onto montmorillonite. Geochim Cosmochim Acta, 4: 5718–5728. Hem, J.D., 1985. Study and interpretation of the chemical characteristics of natural water. U.S. Geological Survey, Water-Supply Paper, 2254: 263 pp. International Agency for Research on Cancer (IARC), 2012. A Review of Human Carcinogens: Metals, Arsenic, Fibres and Dusts, vol. 100C. International Agency for Research on Cancer: Monographs on the Evaluation of Carcinogenic Risks to Humans. Jeong, C.H., 2001. Effect of land use and urbanization on hydrochemistry and contamination of groundwater from Taejon area, Korea. Journal of Hydrology, 253: 194–210. Kaufman, D.B., Dinicola, W., 1970. Acute potassium dichromate poisoning in man. American Journal of Diseases of Children, 119 (4): 347-6. Khan, A., Umar, R., Khan, H., 2015. Significance of silica in identifying the processes affecting groundwater chemistry in parts of Kali watershed, Central Ganga Plain, India. Applied Water Science, 5: 65–72. Lerner, D.N., Harris, H., 2009. The relationship between land use and groundwater resources and quality. Land Use Policy, 26S: 265–273. Liu, A.G., Ming, J.H., Ankumah, R.O., 2005. Nitrate contamination in private wells in rural Alabama, United States. Science of the Total Environment, 346: 112–120. Macler, A.B., Merkel, C.J., 2000. Current knowledge on groundwater microbial pathogens and their control. Hydrogeological Journal, 8: 29–40.

ACCEPTED MANUSCRIPT 34

Omran, A.A., Riad, S., Philobbos, E.R., Othman, B., 2001. Subsurface structures and sedimentary basins in the Nile Valley area as interpreted from gravity data. Egyptian Journal of Geology, 45 (1): 681–712. Powell, K.L., Taylor, R.G., Cronin, A.A., Barrett, M.H., Pedley, S., Sellwood, J., Trowsdale, S.A., Lerner, D.N., 2003. Microbial contamination of two urban sandstone aquifers in the UK. Water Research, 37: 339–352. Qena Irrigation Administration, 2010. Personal communication. Raghunath, H.M., 1987. Groundwater pollution and legislation. In: Groundwater, 2nd edition, India. Said, R., 1981. The Geological Evolution of the River Nile. Springer, 151 pp. Sayed, S., 2004. Effect of the Construction of Aswan High Dam on the Groundwater in the Area between Qena and Sohage, Nile Valley, Egypt. PhD. Thesis, Faculty of Science, Assiut University, 220 pp. Todd, K., 1980. Ground Water Hydrology, 2nd edn. John Wiley & Sons, New York. U.S. Environmental Protection Agency (USEPA), 1994. Report to Congress FY 1994: Fundamental and Applied Research at the Environmental Protection Agency. EPA/600/R94/040. Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC. U.S. Environmental Protection Agency (USEPA), 2004. Potential Sources of Drinking Water Contamination Index (updated September 16th, 2004). Accessed April 2, 2007, at http://permanent.access.gpo.gov/lps21800/www.epa.gov/ safe water/swp/sources1.html.

ACCEPTED MANUSCRIPT 35

Warner, J.W., Gates, T.K., Attia, F.A., Mankarious, W.F., 1991. Vertical leakage in Egypt’s Nile Valley: Estimation and implication. Journal of Irrigation and Drainage Engineering, 117 (4): 515–533. World Health Organization (WHO), 2008. Guidelines for Drinking-water Quality, 3rd ed. (incorporating the first and second addenda), vol. 1, Geneva.

ACCEPTED MANUSCRIPT

The core findings of the article may be summarized in the following points:    

High levels of chemical and microbial contamination at many sites. The main sources of contamination included domestic sewage, agricultural, and industrial effluents. A risk map was constructed to identify the most vulnerable areas. Surface and groundwater are at high risk for contamination by wastewater mixing since the water table is shallow and there is a lack of a formal sanitation network

ACCEPTED MANUSCRIPT

Table (1): Recommended minimum distance between a production well and source of contamination (Raghunath, 1987). Contamination

Recommended

Contamination

Recommended

Source

Distance (m)

Source

Distance

Septic tank

15

Seepage pit

30

Disposal field

30

Cesspool

40

ACCEPTED MANUSCRIPT

Table 2. Physiochemical parameters of surface and groundwater, WT=water table, na = not measured, very shallow wells in bold.

Surface water samples

Groundwater samples

ID

SW

WT T pH

EC

TDS

TH

ORP

µS/cm mg/L mg/L mV 7.8 385/cm 189 275.8 60

K

Na

mg/L

mg/L

Mg

Ca

Cl

SO4 mg/L

HCO3 CO3 NO3 Fe

Zn

Cd

Cr

1

74.5

25

13.8

120.8

33.9

54.6

27.4

6.3

597.8

mg/L mg/L mg/ mg/ mg/ mg/L mg/L mg/L 7.5 16.4 0.154 L 0.121 L 0.007 L 0.031 0.001 0.017

2

65

24 7.1 1101

542

277.4

54

6.88

91.7

36.32

51.24

32.4

14.50

500.2

7.50

6.2

0.201 -

-

0.001

3

73

23 7.9 872

427

375.7

167

14.56

156.63

49.44

68.98

43.7

43.06

768.6

6.0

32.2

0.036 0.023 0.008 0.015

0.001

0.017

4

73

23 8.2 2560

10000

184.5

198

11.2

52.54

25.91

31.19

37.7

56.23

207.40

3.0

26.5

0.017 0.011 0.002 0.002

0.001

0.022

5

72

16 7.8 883

435

341.5

76

9.4

63.7

49.3

55.5

23.5

46.3

494.1

6

9.2

0.131 0.214 0.002 0.017

0.001

0.003

6

-

19 8.1 678

329

136.8

116

6.7

63.7

19.0

23.49

38.9

37.6

213.5

0

8.4

0.034 0.013 0.004 0.011

0.002

0.009

7

65

23 7.7 1392

690

494.7

48

11.34

211.8

69.8

83.1

46.3

123

927.2

6.0

5.2

0.253 0.163 0.007 0.360

-

0.014

8

65

23 7.5 1010

494

410.0

63

12

183.5

58.8

67.3

38.1

81.9

811.3

3

5.3

0.184 0.191 0.006 0.319

0.001

0.014

9

72

26 7.8 1406

699

296.7

107

8.9

176.4

40.8

51.6

55.1

100

555.1

4.5

46.3

0.147 0.091 0.012 0.231

0.006

0.040

10

72

26 7.7 1417

704

321.1

136

14.3

163.9

43.2

57.4

61.7

105

561.2

9

48.1

0.067 0.080 0.013 0.261

0.001

0.031

11

72

24 7.9 1446

717

366.1

124

13.7

188.8

49.9

64.4

67.9

88.5

707.6

6

45.2

0.118 0.089 0.011 0.233

0.003

0.038

12

72

25 8.1 1291

636

308.0

151

17.5

169.5

32.8

69.3

73.2

78.5

599.8

6

48.7

0.051 0.009 0.015 0.172

0.003

0.029

13

72

25 7.8 1778

889

336.7

160

23.7

230.6

45.9

59.2

77.1

149

738.1

4.5

53.6

0.043 0.007 0.017 0.216

0.003

0.008

14

72

23 7.2 1780

893

374.1

331

7.9

331.6

48.2

70.4

21

18

1220

37.5

27.3

0.012 0.001 0.025 0.639

0.012

0.082

15

71.5

20 7.8 3120

1598

292.4

162

31.2

441.8

32.7

63.2

81.3

430

823.5

9

63.8

0.037 0.013 0.023 0.412

0.008

0.063

16

71.5

25 7.8 692

337

283.9

91

15.0

179.7

31.3

62.1

38.7

28.5

610

18

38.4

0.048 0.146 0.022 0.417

0.012

0.043

17

64

26 7.5 1980

1033

369.2

34

27.5

284.9

47.8

69.1

23.9

317

756.4

6

51.2

0.284 0.225 0.007 0.299

0.005

0.014

18

73

25 7.4 1960

980

331.3

129

24.2

481.9

41.5

64.3

134.5

557

793

6

67.8

0.056 0.032 0.018 0.311

0.015

0.049

19

74

25 7.3 1819

910

312.0

132

19.5

346.8

31.4

73.2

146.73

199.7

750.3

9

64.7

0.031 0.017 0.014 0.316

0.013

0.043

20

75

26 7.5 4620

2410

303.9

101

13.35

360.41

30.4

71.6

133.21

370

652.7

12

72.4

0.062 0.084 0.011 0.391

0.006

0.053

21

75

23 7.2 1970

980

385.0

98

27.7

446.9

42.7

83.8

166.3

330

933.3

39

69.6

0.113 0.105 0.014 0.427

0.013

0.063

22

-

25 7.4 1608

799

316.8

116

11.5

310.3

29.1

78.9

72.1

298

671.0

9

46.2

0.109 0.077 0.008 0.381

0.007

0.023

23

71.5

20 7.4 1785

890

353.7

41

45.3

360.4

43.6

69.8

192.7

254.4

683.2

12

96.1

0.201 0.180 0.012 1.251

0.013

0.077

24

72

16 7.5 2536

1854

424.4

140

19.7

364.8

49.8

87.9

74.6

474

768.6

6

51.1

0.112 0.076 0.009 0.273

0.008

0.011

25

65

22 8

273

194.7

46

7.6

233.7

24.5

37.6

32.9

77.5

744.2

0

9.5

0.213 0.137 0.003 0.088

0.003

0.032

26

72

18 7.9 2920

1471

394.8

188

32.4

390.3

39.2

93.5

27.5

502.4

815.4

3

52.3

0.064 0.003 0.007 0.192

0.006

0.028

27

-

26 7.5 2828

1487

234.3

143

9.4

240.2

28.3

47.2

23.1

143

732

6

41.1

0.081 0.079 0.005 0.113

0.004

0.047

28

73

26 7.3 2020

1016

238.0

113

16.9

253.0

31.2

43.9

21.8

130

750.3

15

53.1

0.155 0.136 0.001 0.191

0.009

0.027

29

-

27 7.4 1520

1061

274.1

130

14.1

190.2

36.4

49.8

22.5

84.6

756.4

9

21.1

0.100 0.069 0.009 0.121

0.005

0.033

30

63

25 7.5 1141

563

260.2

41

9.5

173.1

34.9

46.7

52.1

26.3

658.8

15.0

8.2

0.243 0.217 0.005 0.003

-

0.008

31

63

25 7.5 1114

548

198.8

47

9.6

198.9

27.2

34.8

39.6

63.3

622.2

10.5

21.7

0.217 0.261 0.007 0.032

0.003

0.002

32

63

26 7.1 1448

718

237.5

32

8.5

229.4

32.6

41.4

32.21

20.2

829.6

9.0

18.1

0.239 0.283 -

0.045

0.001

0.001

33

-

25 7.3 1512

752

250.7

29

10.8

216.6

29.8

51.3

38.5

81.0

750.3

13.0

27.3

0.262 0.276 -

0.049

0.002

0.006

Min

63

16 7.1 385

189

136.8

29

6.7

52.54

19

23.49

21

6.3

207.4

0

5.2

0.012 0.001 0.001 0.002

0.001

0.001

Max

75

27 8.2 4620

10000

494.7

331

45.3

481.9

69.8

93.5

192.7

557

1220

39

96.1

0.284 0.283 0.025 1.251

0.015

0.082

Avg. 34

70.1

23 7.6 1718.8

1357.5

308.2

113.3

16.5

241.2

38.8

59.9

63.2

168.5

698.0

10.1

38.7

0.125 0.106 0.010 0.264

0.006

0.030

-

21 8.5 272

131

127.3

223

7.8

64.2

17.4

22.3

24.6

19.8

250.1

4.5

28.9

0.011 0.006 0.003 0.002

0.001

0.026

35

-

16 8.5 347

181

138.5

201

9.8

56.11

23.14

17.32

21.16

20.60

219.6

12.0

38.2

0.002

0.041

36

-

19 7.9 812

401

326.7

71

33.1

153.5

47.38

52.77

43.33

64.90

677.1

7.5

58.6

0.014 0.009 0.211 0.019 0.031 0.017 0.342

0.002

0.051

37

-

19 8.1 1075

529

354.5

61

29.91

157.5

49.94

59.66

38.37

61.80

719.8

6.0

61.2

0.013 0.006 0.018 0.307

0.008

0.050

38

-

19 9.2 401

193

162.1

57

19.55

78.2

22.89

27.20

48.67

31.60

213.5

3.0

74.2

0.011 0.007 0.014 0.431

0.008

0.062

39

-

19 9.2 287

139

388.2

43

14.27

91.2

59.88

56.77

62.37

27.40

524.6

0.0

97.4

0.013 0.005 0.013 0.523

0.012

0.082

40

-

20 8.4 299

144

198.8

68

23.22

76.1

30.11

29.99

61.09

29.0

280.6

4.50

54.3

0.029 0.002 0.011 0.201

0.006

0.053

41

-

19 7.9 281

135

167.4

302

17.41

66.8

24.10

27.33

47.22

19.80

256.2

0.0

28.4

0.025 0.001 0.009 0.025

0.004

0.049

42

-

23 7.8 1285

637

320.6

99

38.33

162.5

43.11

57.33

19.64

13.2

732

9.0

68.9

0.071 0.023 0.007 0.642

0.005

0.103

43

-

19 7.8 2311

1168

457.1

61

39.9

379.5

58.1

87.3

72.96

479.5

866.2

9.0

49.2

0.121 0.091 0.013 1.110

0.011

0.114

44

-

20 8.3 284

137

130.5

180

9.4

65.5

16.6

24.9

21.4

57.2

213.5

0.0

26.1

0.061 0.003 0.006 0.104

0.006

0.034

45

-

19 8.2 280

135

59.7

172

10.1

90.2

7.22

12.0

30.16

87.6

158.1

3.0

38.1

0.007

0.040

Min Max

-

16 7.8 272

131

59.7

43.0

7.8

56.1

7.2

12.0

19.6

13.2

158.1

0.0

26.1

0.093 0.007 0.213 0.011 0.001 0.003 0.002

0.001

0.026

-

23 9.2 2311

1168

457.1

302.0

39.9

379.5

59.9

87.3

73.0

479.5

866.2

12.0

97.4

0.121 0.091 0.018 1.110

0.012

0.114

Avg.

-

19 8.3 751

373.5

239.2

134.5

21.5

134.0

33.4

41.0

41.7

100.4

438.3

5.0

53.4

0.044 0.020 0.011 0.373

0.006

0.060

-

30 6.7 667

453

140

na

na

na

na

na

45

44

250

na

25

1.31

0.0004 na

562

mg/L

Mn Pb

°C

-

mg/L mg/L

mg/L

m

0.06

0.006 0.162

0.01

na

ACCEPTED MANUSCRIPT

Table 3: Results of the bacteriological analysis (count CFU/100 ml) of selected 17 groundwater and 8 surface water samples, SW (sewage water from El-Salhiya sewage treatment plant at Qena). I

Total Coliform

Type of detected Bacteria

(E .coli))

D

Groundwater samples Surface water samples SW

Fecal Coliform

1

45

0

pseudomonas, Klebsiella

2

8

0

Klebsiella

3

21

3

Pseudomonas

4

38

2

E.coli, Klebsiella.

5

16

0

Klebsiella

6

48

3

Klebsiella

7

36

6

E.coli, Pseudomonas

8

42

0

Klebsiella, Pseudomonas

9

388

64

E.coli,Klebsiella,Pseudomonas

10

490

82

E.coli, Klebsiella, Pseudomonas

11

560

74

E.coli, Klebsiella, Pseudomonas

12

720

112

E.coli, Klebsiella, Pseudomonas

13

38

11

E.coli, Klebsiella

14

18

0

Klebsiella

15

24

0

Klebsiella

16

58

8

E.coli, Klebsiella

17

36

0

E.coli, Pseudomonas

34

120

46

E.coli, Pseudomonas

35

312

102

E.coli, Salmonella, Pseudomonas

36

680

67

E.coli, Klebsiella, Pseudomonas

37

190

18

E.coli, Pseudomonas

38

840

180

E.coli, Pseudomonas, Klebsiella, Salmonella

39

965

224

E.coli, Pseudomonas, Klebsiella, Salmonella

41

87

39

E.coli, Klebsiella

45

128

41

E.coli, Salmonella, Pseudomonas

1,800,000

106,000

-

1