Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan

JES-01384; No of Pages 12 J O U RN A L OF E N V I RO N ME N TA L S CI EN CE S X X (2 0 1 7 ) XX X–XXX

Available online at www.sciencedirect.com

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Kifayatullah Khan1,2 , Yonglong Lu2,3,⁎, Mian Abdal Saeed1 , Hazrat Bilal1 , Hassan Sher 4 , Hizbullah Khan5 , Jafar Ali3,6 , Pei Wang2 , Herman Uwizeyimana2,3 , Yvette Baninla2,3 , Qifeng Li2,3 , Zhaoyang Liu2,3 , Javed Nawab7 , Yunqiao Zhou2,3 , Chao Su2,3 , Ruoyu Liang2,3

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1. Department of Environmental and Conservation Sciences, University of Swat, Swat 19130, Pakistan 2. State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 3. University of Chinese Academy of Sciences, Beijing 100049, China 4. Center for Plant Science and Biodiversity, University of Swat, Swat 19130, Pakistan 5. Department of Environmental Sciences, University of Peshawar, Peshawar 25120, Pakistan 6. Laboratory of Environmental Nanomaterials, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 7. Department of Environmental Sciences, Abdul Wali Khan University, Mardan, Pakistan

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Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan

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Article history:

Fecal bacteria contaminate water resources and result in associated waterborne diseases. 23

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Received 24 July 2017

This study assessed drinking water quality and evaluated their potential health risks in 24

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Revised 2 December 2017

Swat, Pakistan. Ground and surface drinking water were randomly collected from upstream 25

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Accepted 5 December 2017

to downstream in the River Swat watershed and analyzed for fecal contamination using 26

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Available online xxxx

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Keywords:

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Drinking water

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Fecal contamination

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Health risks

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Pakistan

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fecal indicator bacteria (Escherichia coli) and physiochemical parameters (potential of 27 hydrogen, turbidity, temperature, electrical conductivity, total dissolved solid, color, odor 28

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locations, whereas, the fecal contaminations in drinking water resources exceeded the 30

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and taste). The physiochemical parameters were within their safe limits except in a few 29 drinking water quality standards of Pakistan Environmental Protection Agency (Pak-EPA), 31 2008 and World Health Organization (WHO), 2011. Multivariate and univariate analyses 32 revealed that downstream urbanization trend, minimum distance between water sources 33 and pit latrines/sewerage systems, raw sewage deep well injection and amplified urban, 34 pastures and agricultural runoffs having human and animal excreta were the possible 35 sources of contamination. The questionnaire survey revealed that majority of the local 36 people using 10–20 years old drinking water supply scheme at the rate of 73% well supply, 37 13% hand pump supply, 11% spring supply and 3% river/streams supply, which spreads 38 high prevalence of water borne diseases including hepatitis, intestinal infections and 39 diarrhea, dysentery, cholera, typhoid fever, jaundice, and skin diseases in children followed 40 41

by older and younger adults.

© 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. 42 Published by Elsevier B.V. 43

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⁎ Corresponding author. E-mail: [email protected] (Yonglong Lu).

https://doi.org/10.1016/j.jes.2017.12.008 1001-0742/© 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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Drinking water is a vital substance in the environment and a cherished gift of the nature to human beings, particularly to a society where natural water resources are limited (Khan et al., 2013b; Zhang et al., 2016). However, water also acts as a passive carrier for numerous organisms that can cause human illness including viruses, protozoa, and bacteria (Coleman et al., 2013; Ali et al., 2017; Cui et al., 2017). Water quality deterioration with both point sources of pollution (e.g., discharge of wastewater) and non-point sources of pollution (e.g., sewer leakages, overflow discharges, wildlife animal wastes and runoff from urban areas or agricultural fields) resulted from unprecedented population and economic growth, urbanization and industrialization has been a great concern for several decades (Åström et al., 2007; Parajuli et al., 2009; Sánchez et al., 2015; Tran et al., 2015). Drinking water sources in the world where the gastroenteritis diseases are the major contributor to human morbidity are continuously overexploited and polluted with various microbial (bacteria, fungi, parasites, viruses) and physiochemical contaminants (Hussain et al., 2014; Hillebrand et al., 2015). Drinking water quality based on pathogenic parameters is primarily determined using indicator organisms to indicate the fecal contamination. The availability of indicators organisms is often a key in assessing the pathogenic caused health risks and used worldwide in the drinking water quality regulations and guidelines (Wanda, 2008). In developed countries like United States, the Safe Drinking Water Act requires drinking water systems to be analyzed for pathogens including total coliforms and Escherichia coli (E. coli) either once a month for the smallest systems or 480 times per month for the largest ones. However, due to limited resources this kind of sampling is not always achievable in developing countries (Kostyla et al., 2015). In developing counties like Pakistan, the microbial contamination of drinking water is regarded the most serious problem; where the situation of fresh water availability is worse due to lack of proper management and poor financial constraints (Muhammad et al., 2010; Azizullah et al., 2011). Normally contamination is caused by biological pollutants from the surrounding sources like toilets, underground damaged sewerage lines, seepage/percolation from drainage system and poor efficiency of the Waste Water Treatment Plants, which ultimately results in severe illness and even deaths (Khalid et al., 2011; Khan et al., 2013b). To monitor water quality and ensure the provision of safe drinking water, the World Health Organization (WHO) and United States Environmental Protection Agency (US EPA) have proposed to check fecal contamination of drinking water using fecal indicator bacteria (FIB) (Kostyla et al., 2015; Paule-Mercado et al., 2016). E. coli is currently recognized as the best FIB for monitoring fecal contamination in drinking water and the key indicator of health risk for both marine and fresh recreational waters (Pettus et al., 2015; Wang et al., 2015). Whereas, the WHO guideline value in drinking water is “none detectable in any 100-mL sample” for human consumption. E. coli occurs in high numbers in human and animal feces, whereas water nutrient conditions and other physical, chemical, biochemical and biological parameters existing in drinking-water distribution systems may highly support the growth of these organisms

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(WHO, 2011). Its high levels in water sources constitute potential infections and frequent waterborne diseases to humans, especially children and old people and thus impair several waters uses (Bachoon et al., 2010; Walker et al., 2013; Gerhard et al., 2017). Each year in Swat, Khyber Pakhtunkhwa Pakistan, governmental agencies and non-government organizations (NGOs) develop and improve thousands of wells, boreholes, springs and other sources of water supply to provide desperate villages with communal sources of safe drinking water. However, the water quality at the point-of-use is continuously degrading in the area with availability of high fecal and physiochemical contaminants, resulting in serious waterborne diseases including diarrhea, intestinal infections, dysentery, cholera, hepatitis, typhoid fever, vomiting, skin diseases and other related illnesses especially in children and older adults. The objective of the present study was to assess the drinking water quality at the point-of-use based on pathogenic (E. coli) and physiochemical (potential of hydrogen (pH), turbidity, temperature, electrical conductivity (EC) and total dissolved solid (TDS)) parameters, and to identify the possible sources of the contaminants and potential human health risks.

1. Materials and methods

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Introduction

1.1. Study area

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The study area, District Swat, is comprised of seven tehsils called tehsil Bahrain, Khwazakhela, Matta, Charbagh, Babozai, Kabal and Barikot (Fig. 1). Geographically, the district is located between 34°34́’ to 35°55′ north latitude and 72°10́’ to 72°50́’ east longitude with an altitude ranging from 733 m in the south to approximately 5740 m in the north of Khyber Pakhtunkhwa, Pakistan. Its total population is approximately 1.25 million, with an average density of 248 people per km2 (Khan et al., 2014). The climate is Mediterranean in the northern parts of the district and Sub-tropical in the southern parts with average temperature ranged from −10 to 25°C (Shah et al., 2010; Khan et al., 2013a), and with average rainfall from 750 to 1350 mm and humidity varied from a minimum of 40% in April to a maximum of 85% in the month of July (Shah et al., 2010). Besides, the area has been gifted with rich fresh water resources. The River Swat is the main source of water in the valley that originates in the Hindukush Mountains and flows at 171.76 m3/sec downward through the Valley of Kalam in a narrow gorge with a rushing speed up to Madyan, and then gradually spreads in the lower plain areas of Valley up to Chakdara for about 160 km (Ghumman et al., 2010; Khan, 2011). This river plays an important role in the economic development of the valley, where its esthetic value can never be underestimated. It provides water for irrigation, drinking and other domestic uses, and recharges the surrounding groundwater well and spring sources (Khan et al., 2013b). However, the water has been increasingly polluted particularly with biological contaminants. Surface river water may have been significantly contaminated from the direct discharge of municipal sewage and hotel flushes along with surface runoffs from surrounding livestock manure, and the groundwater may have been affected by direct seepages/leakages of surrounding toilets and fragile sewerage lines. Thus, due to lack of proper management and

Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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Fig. 1 – Location map of the study area, showing the sampling sites in District Swat, Pakistan.

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poor financial constraints the biologically contaminated water may further affect the health of local human communities.

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1.2. Sampling

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All the drinking water samples were collected in the years 2015–2016 in seven different tehsils (Bahrain, Matta, Khwazakhela, Charbagh, Babozai, Kabal and Barikot) of the study area along the downstream of River Swat watershed. A total of 198 water samples including 139 groundwater and 58 surface water samples (Fig. 1) were randomly collected in sterilized high-density polypropylene containers from different water resources including tube wells, dug wells, hand pumps, springs, streams and rivers. Briefly, the water from tube well, hand pump, and springs supplies were run for 2 to 5 min before sampling, where in the case of stream and river, the composite

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water samples (500 mL) were collected on the surface of water source at a depth of 0.5 m using a water sampler. Residual chlorine in each water sample was reduced by adding 200 μL of 200 mg/mL of sodium thiosulfate solution (Wanda, 2008; Machado and Bordalo, 2014; Wang et al., 2015). All the collected water samples were stored in dark and brought to the laboratory in ice as soon as possible for immediate analysis.

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1.3. Analytical procedures

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E. coli is the most widely used FIB and has been proposed as the best microbial bacterial indicator to predict the sanitary risk associated with waters (Madoux-Humery et al., 2013). In this study, the E. coli assessments in drinking water samples were carried out via membrane filter method using Delagua portable incubator (Wagtech International Potatest WE10005, Team Valley

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Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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1.5. Statistical analysis

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Statistical analyses were conducted using Statistical Package for the Social Sciences (SPSS) version 17 and Microsoft Excel, version 2010. Multivariate and univariate statistical analyses including one-way ANOVA, correlation analysis and principle component analysis (PCA) were performed to determine the significant differences and potential source apportionment, whereas the location map of the study area was prepared using Arc-GIS computer package.

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The E. coli presence in drinking water indicates that the water sources are contaminated by humans or other warm-blooded animal's fecal material, and shows the potential for the presence of pathogenic organisms as well (Pote et al., 2009). Table 1 summarizes the detected fecal contamination in drinking water samples collected from upstream towards downstream in seven tehsils of the District Swat including Bahrain, Matta, Khwazakhela, Charbagh, Babozai, Kabal and Barikot, respectively. The overall fecal contaminations of drinking water from both surface and groundwater along the upstream in seven tehsils of the study area were found in the order of tehsil Bahrain < Matta < Khwazakhela < Charbagh < Babozai < Kabal < Barikot, respectively. In total 198 water samples, 78.42% of the total groundwater samples were found above the Pak-EPA (2008) and WHO (2011) permissible limits, while 96.70% of the total surface water was recorded heavily fecal contaminated. The average mean fecal contamination in total surface and groundwater samples were 30.43 MPN/100 mL and 12.23 MPN/100 mL, respectively. Briefly, the mean fecal contamination in groundwater collected from tehsil Bahrain, Matta, Khwazakhela, Charbagh, Babozai, Kabal and Barikot were 03.91 ± 04.69, 8.12 ± 07.66, 10.00 ± 09.90, 11.90 ± 14.13, 13.65 ± 15.85, 14.69 ± 16.12 and 23.33 ± 24.79 MPN/100 mL, respectively (Table 1). The average maximum fecal contamination (23.33 MPN/100 mL) was recorded in the groundwater collected at tehsil Barikot and the lowermost (03.91 MPN/100 mL) at tehsil Bahrain showing continued fecal increase from upstream towards downstream in the study area (Fig. 2a). Briefly the highest groundwater fecal contamination (> 100 MPN/100 mL) was recorded in the spring, tube well and bore well water at tehsil Barikot; spring and dug well water at tehsil Kabal; spring, tube well and dug well water at tehsil Babozai; dug well water at tehsil Charbagh; tube well and dug well water at tehsil Khwazakhela; hand pump and dug well water at tehsil Matta; and only in spring water at tehsil Bahrain; While the lowest fecal contamination (1.00 MPN/100 mL) was noted in the dug well and tube well water at tehsil Kabal, tube well water at tehsil Babozai, dug well, hand pump and tube well water at tehsil Charbagh, hand pump and spring water at tehsil Khwazakhela, and spring water at tehsil Bahrain. This high fecal contamination towards downstream in drinking groundwater resources could be influenced by downstream urbanization and amplified seepage/leakages of sewage, toilets and domestic effluents into the groundwater sources. Similarly, the mean surface water fecal contaminations at tehsils Bahrain, Matta, Khwazakhela, Charbagh, Babozai, Kabal and Barikot were 7.26 ± 4.91, 17.60 ± 17.21, 23.00 ± 17.27, 25.40 ± 18.67 and 38.20 ± 21.46, 39.83 ± 23.62 and 61.20 ± 35.31 MPN/100 mL, respectively (Table 1). The average maximum surface water fecal contamination (61.20 MPN/100 mL) was recorded at tehsil Barikot and the lowermost (7.26 MPN/100 mL) at tehsil Bahrain (Fig. 2a). Both the highest (>100 MPN/100 mL) and the lowest (2.00 MPN/100 mL) surface water fecal contamination were recorded in the river and stream water at tehsil

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To assess the prevailing adverse impacts of contaminated water in the study area, a random questionnaire (Appendix A Table S1) survey was conducted among the residents of the area through a survey team consisting of medical experts and environmentalists. The survey was aimed to find out the hygienic conditions and prevalence of different infectious and water borne diseases and also to create awareness about the potential consequences of contaminated water. All the participants were randomly selected and interviewed for the information on demographics, hygiene instruction and practices, sanitation facilities and water collection, storage practices and portable drinking water sources. Every respondent was also enquired about his/her age, body weight, monthly income, smoking habits, occupational exposure, infectious and waterborne diseases and other health related problems. At a last resort, interviews were also conducted with medical doctors in the local hospitals and basic health units to collect the data regarding waterborne diseases in the study area. All the required questionnaires and sampling surveys were completed in 78 local visits from April 2015 to March 2016. The details of the local survey visits conducted in this study are summarized in Appendix A Table S5.

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2. Results and discussion

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Gates head NE110NS, UK). Briefly, the water samples (100 mL) were filtered for E. coli content through sterile cellulose nitrate/ ester membranes (0.45 μm pore size, 47 mm diameter, GE Healthcare Life Sciences, Little Chalfont, UK). The membranes were placed on the selective media m-fecal coliform agar plates (Difco, Franklin Lakes, NJ, USA) and incubated at 37–45°C for 24 hr. The coliform bacteria (E. coli) as the most probable number (MPN) were counted after 24 hr using tubes or microtitre plates based on presence/absence tests (Xiao et al., 2013; Xu et al., 2017). Moreover, the physiochemical parameters such as pH, EC, TDS, temperature and salinity were examined using standard procedures described by Khan et al. (2013b), Khan et al. (2013). Briefly, pH and temperature of the samples were measured at the time of collection using portable battery-operated pH meter (Model WAG-WE30020, Team Valley Gates head NE110NS, UK). Where, the EC was measured in the laboratory by using digital conductivity meter (Model HI 98303, USA), and TDS using TDS meter (Model S518877, Team Valley Gates head NE110NS. UK). Besides, the reliability and reproducibility of the analysis were checked by analyzing blank standard and pre-analyzed sample after every 10 samples. In addition, color, odor and taste of the water samples were analyzed physically during sampling on the spot and compared with the Pakistan Environmental Protection Agency (Pak-EPA), 2008 and WHO, 2011 recommended standards.

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Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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Table 1 – Fecal contamination (MPN a/100 mL) of the surface and groundwater samples (n b = 198) collected in seven tehsils of District Swat, Pakistan.

Matta Khwazakhela Charbagh Babozai Kabal Barikot

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00.00–12.00 00.00–16.00 00.00–20.00 07.00–48.00 00.00–31.00 03.00–46.00 00.00–37.00 09.00–57.00 00.00–46.00 20.00–73.00 00.00–53.00 01.00–62.00 00.00–87.00 04.00–91.00

03.91 07.26 08.12 17.60 10.00 23.00 11.90 25.40 13.65 38.20 14.69 39.83 23.33 61.20

Most probable number. Number of samples. Standard deviation. Source: Pakistan Environmental Protection Agency (Pak-EPA, 2008. source: World Health Organization (WHO, 2011). Groundwater (springs, dug well and tube well). Surface water (river).

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Permissible limits Pak-EPA d/WHO e Must not be detected in 100 mL of water

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2.2. Physicochemical contamination of water resources

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Drinking water sources polluted with different physicochemical contaminants may also be responsible for numerous health related consequences. In this study, the local dwellers mostly belong to low-income class and are unable to afford mineral water or filter water. That is why the selected water sources used for drinking and domestic purposes were also tested for different physiochemical parameters. The overall mean physicochemical parameters/contaminants in drinking water sources were observed as pH (groundwater: 7.51, surface water: 7.52), TDS (groundwater: 391.23 mg/L, surface water: 196.63 mg/L), EC

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Barikot, Kabal, Babozai, Charbagh, Khwazakhela, Matta and Bahrain, respectively. This high surface water fecal contamination towards downstream in River Swat and streams could be attributed to increasing downstream urbanization trend, surrounding agricultural runoffs, direct discharge of municipal effluents, and excreta from human beings and other homeotherms, that may spread related potential health risks in the local community (Wanda, 2008; Azizullah et al., 2011; Cui et al., 2017; Xu et al., 2017). The overall drinking water fecal contamination in seven tehsils showed increasing order from upstream towards downstream in the study area. However, the maximum E. coli colony formation in this study was detected significantly lower than those of Shar et al. (2008a) and (2008b) conducted in Khairpur Sindh and higher than those reported by Nawab et al. (2016) in Malakand and Shungla districts, Khan et al. (2013) in Charsada, Zahoorullah et al. (2003) in Peshawar valley and Hashmi et al. (2009) in Rawalpindi Pakistan. The detailed information on fecal contamination (MPN/100 mL) of both ground and surface drinking water samples (n = 198) collected in the study area are given in Appendix A Tables S3 and S4.

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(groundwater: 562.02 μS/Cm, surface water: 366.20 μS/Cm), and remained within the Pak-EPA (2008) and WHO (2011) safe limits with a little variation. As we know, pH is one of the most significant water quality parameters in the aquatic system, and its high range may possibly confer a bitter taste to drinking water. The fluctuation of pH affects particularly mucous membrane, results in bitter taste, and causes corrosion (Patil et al., 2012; Khan et al., 2013b). Beside direct impacts, pH of water can also affect human health indirectly by bringing changes in other water quality parameters such as solubility of metals and survival of pathogens including fecal coliforms. Its highest value (7.67) in groundwater was recorded at tehsil Charbagh, while the lowest (7.32) at tehsil Barikot; whereas in surface water its highest value (7.88) was recorded at tehsil Khwazakhela and the lowest (6.98) at tehsil Matta (Fig. 2b). This variation in the pH value may be due to a consequence of low photosynthetic activity, less assimilation and incorporation of carbon dioxide and bicarbonates. Similarly the TDS (carbonates, bicarbonates, chlorides, phosphates and nitrates of calcium, magnesium, sodium, potassium and manganese, organic matter, salt and other particles) may possibly contribute in the taste impairment, gastro-intestinal irritation, corrosion or incrustation (Mahananda et al., 2010; Patil et al., 2012). The higher the TDS in water the higher the chemical and biological oxygen demand that will lead to decreasing level of dissolved oxygen in water. In the study area from upstream towards downstream of River Swat watershed, the overall groundwater TDS values were in the order of tehsil Bahrain < Matta > Khwazakhela < Charbagh < Babozi < Kabal < Barikot, while for surface water its values remained in the order of tehsil Behrain < Matta > Khwazakhela < Charbagh < Babozi < Kabal < Barikot (Fig. 2e). Its value in groundwater ranged from 61.83 mg/L in tehsil Bahrain to 913.27 mg/L in tehsil Barikot,

Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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while in surface water its value fluctuated from 53.56 mg/L in tehsil Bahrain to 730.40 mg/L at tehsil Barikot, which may cause gastrointestinal irritation and constipation effects in the local dwellers (Fig. 2c). This higher TDS values in groundwater resources may be due to the minimum distance between the water sources and urban settlements (industries, residential areas and other human infrastructure) and increased human activities such as construction, demolition and other developmental activities. Likewise the EC value in drinking water varies from point to point and from source to source in the study area, which may be due to the infiltration of sewerages near populated areas (Hassan et al., 2010; Patil et al., 2012). Its mean value in the groundwater varied from 127.42 μS/Cm in tehsil Bahrain to 791.27 μS/Cm in tehsil Barikot, whereas its value in surface water remained from 119.87 μS/Cm in tehsil Bahrain to 1225.00 μS/Cm in tehsil Barikot

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Fig. 2 – Overall fecal and physiochemical pollution in drinking water samples (n = 198) collected from upstream to downstream in seven tehsils of the study area. (a) Fecal contamination; (b) pH; (c) total dissolved solid; (d) electrical conductivity; (e) total dissolved solid.

(Fig. 2d). The reason for downstream increasing EC in the water sources may be associated with increasing population in the downstream urban areas. However, the chemical, biochemical and biological behaviors of water might be influenced by water temperature. Its mean value in ground and surface water sources ranged from 9.09°C to 15.42°C and 11.35°C to 18.07°C, respectively (Appendix A Table S2). Turbidity in water is associated with the inability of light spectrum to reach the depth of water. Its value in majority of the drinking water sources were within their permissible limits except in few surface water sources at tehsil Bahrain, Khwazakhela and Barikot, which may be due to the erosion of loose soil from the embankments, and may ultimately be associated with bacteria causing diseases (Appendix A Table S2). Consistently, the other physical parameters like color, odor and taste in all groundwater samples were recorded within the acceptable levels set by

Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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Table 2 – One-way ANOVA comparison of selected water quality parameters in the study area. Parameter

Comparison

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E. coli d

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One-way ANOVA was used for the statistical variation of selected fecal and physiochemical parameters in different sampling locations. The results revealed significant contaminant variation (p < 0.05) between the drinking water sources of tehsil Bahrain, Matta, Khwazakhela, Charbagh, Babozai, Kabal and Barikot; suggesting that each tehsil in the study area may contribute differently to the mean fecal (E. coli) and physiochemical impurity in selected drinking water sources (Table 2). In brief, the E. coli contaminations in both ground and surface drinking water samples collected from tehsil Barikot were significantly higher (p ≤ 0.01) at the rate 54 degrees of freedom than the drinking water sources of tehsil Babozai, Kabal, Charbagh, Khwazakhela, Matta and Bahrain (Table 2 and Fig. 2a). Similarly, the pH values in the surface water of selected tehsils were comparatively higher (p ≤ 0.01) at the rate of 26 degrees of freedom than the pH of ground water sources (Table 2 and Fig. 2b). The saturations of TDS in the drinking water sources of tehsil Barikot were significantly higher (p ≤ 0.01) at the rate of 185 degrees of freedom than the TDS values of tehsil Kabal followed by tehsil Babozai > Charbagh > Matta > Khwazakhela > Bahrain (Table 2 and Fig. 2c). The levels of ECs in the surface water of Barikot were significantly higher (p ≤ 0.01) at the rate of 327 degrees of freedom than the water resources of tehsil Kabal,

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Babozai, Charbagh, Khwazakhela, Matta and Behrain (Table 2 and Fig. 2d). Where the temperature of the water sources in tehsil Behrain was significantly higher (p ≤ 0.01) at the rate of 297 degrees of freedom than the water drinking water sources of tehsil Khwazakhela followed by tehsil Matta Charbagh, Babozai, Kabl and Barikot, respectively (Table 2 and Appendix A Tables S3 and S4). The probable reason for this statistical difference in selected contamination may be associated with available natural and anthropogenic sources, and each parameter may have a different variation value for an individual location in the study area (Table 2). As the physicochemical properties of the water may influence the fate and distribution of pathogenic contaminants in the aquatic environment, Pearson's correlation statistics with 2-tailed significance were implied between the detected fecal (E. coli) and physiochemical parameters to predict their accumulation and respective pathways in drinking water sources (Table 3). The results revealed that total contamination of each pathogenic and physiochemical parameter in drinking water may have a close relationship with the fraction of each corresponding parameter. In both ground and surface water sources the correlation analysis showed a significantly strong correlation between E. coli-TDs, E. coli-EC, TDS-EC, E. coli-TDS, E. coli-EC and TDS-EC (Table 3). This correlation ship between the pathogens (E. coli) and physiochemical parameters suggest that these contaminations might originate from some common pollution sources. The physiochemical parameters of aquatic environment may stimulate the pathogenic levels, which are usually influenced by multiple inputs. The detected E. coli contaminations in ground water sources were significantly correlated with the levels of TDS (r = 0.917**) and EC (r = 0.805*) in the same water source (Table 3). This result revealed that the TDS and EC may play an important role in determining the environmental

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Pak-EPA (2008) and WHO (2011), while it was exceptional for a few surface water samples collected in tehsil Bahrain, Matta, Kabal and Barikot (Appendix A Table S2). The detailed physicochemical contaminations of both ground and surface drinking water samples (n = 198) collected in the study area are given in Appendix A Tables S3 and S4.

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Sum of squares

df a

11,095 66,496 77,591 1.78 22.39 24.16 5,997,601 1.04 1.64 1.66 1.64 3.30 1 392 393

1 322 323 1 322 323 1 322 323 1 322 323 2117.51 2796.62 4914.14

Fb

Sig c

11.95 206.50

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0.00

1.78 0.07

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0.00

5,997,601 32,443

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0.00

1.66 50,839.20

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0.00

2117.51 7.13

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0.00

Mean squares

The main difference is significant at the level of 0.05. Degree of freedom b Factor c Significance d Escherichia coli e Potential of hydrogen f Total dissolved solid g Electric conductivity h Temperature a

Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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Table 3 – Correlation matrixes of pathogenic and physiochemical parameter in the drinking water (n a = 198). EC e

Temp. f

t3:5 t3:6 t3:7 t3:8 t3:9 t3:10 t3:11 t3:12 t3:13 t3:14 t3:15 t3:16 t3:17

Groundwater (n = 139) E. coli pH TDS EC Temp

t3:18 t3:19 t3:20 t3:21 t3:22 t3:24 t3:23 t3:25 t3:26 t3:27 t3:28 t3:29 t3:30 t3:31

Further, to apportion the possible sources of ground and surface drinking water contamination in the study area, multivariate statistical analysis, such as PCA (Varimax Kaiser Normalization) with three factors based on components and rotational component matrixes were applied (Table 4 and Fig.3). a Number of water samples. b Escherichia coli. c Potential of hydrogen. d Total dissolved solid. e Electric conductivity. f Temperature. ⁎⁎ Correlation is significant at the 0.01 level. ⁎ Correlation is significant at the 0.05 level.

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t4:1

1.000 0.206

1.000

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1.000 0.997 ⁎⁎ 0.188

1.000

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1.000 −0.023 0.023 −0.364

1.000 0.426

behavior of E. coli in available aquatic environment. The detected TDS levels in the ground drinking water sources were significantly correlated with levels of EC (r = 0.763*) in the same water source (Table 3), while in surface water resources the

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1.000 0.131 0.860 ⁎ 0.891 ⁎⁎ 0.524

1.000 0.763 ⁎ 0.024

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0.090

1.000 −0.577 −0.573 −0.227

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Surface water (n = 59) E. coli pH TDS EC Temp

1.000 −0.536 0.917 ⁎⁎ 0.805 ⁎

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detected E. coli contaminations were significantly correlated with levels of TDS (r = 0.860*) and EC (r = 0.891**), and the detected TDS level in surface water was significantly correlated with level of EC (r = 0.997**) in the same water source (Table 3). Moreover, the rest of physical parameters may influence the E. coli contamination in both ground and surface water sources more or less. The results revealed the total cumulative variance for three factors in groundwater as 95.625%, in which Factor-1 contributed (50.917%), Factor-2 (23.254%) and Factor-3 (21.454%) to the total variance with a high loading on E. coli (r = 0.949), TDs (r = 0. 922), EC (r = 0. 821), Temperature (r = 0. 985) and pH (r = 0. 930) (Table 4 and Fig. 3a). With regard to surface water, the total cumulative variance for three factors was 99.686%, in which Factor-1 contributed (54.918%), Factor-2 (23.742%) and Factor-3 (21.026%) to the total variance with a high loading on E. coli (r = 0.860), TDS (r = 0.996), EC (r = 0.997), Temperature (r = 0.967) and pH (r = 0.985) (Table 4 and Fig. 3b). The results of Factor-1, Factor-2 and Factor-3 suggest that both ground and surface water sources contamination may be due to natural and anthropogenic contributions. The variation in fecal contamination from upstream towards downstream in groundwater sources may be attributed to downstream urbanization trend, poor management, weak disposal systems, raw sewage deep well injection and amplified seepage/leakages of human pit latrines and domestic sewages into groundwater sources, while for surface water the variation could be influenced by downstream increasing urbanization and hoteling tendency, direct discharge of municipal sewages having humans and animals excreta, and surface runoffs from the urban localities, pastures and agricultural fields. Similarly, the variation in physiochemical parameters including pH in selected water sources may be attributed to photosynthetic activity and

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Table 4 – Factor loading for selected pathogenic and physiochemical parameters in the drinking water (n a = 198).

t4:3 t4:2

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Component matrix

t4:5

t4:23 t4:24 t4:25 t4:26 t4:27 t4:28

a

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Surface water (n = 59) E. coli pH TDS EC Temperature Variance (%) Cumulative (%)

b c d e f

Factor 3

Factor 1

Factor 2

Factor 3

0.922 −0.744 0.913 0.918 0.306 63.454 63.454

−0.242 −0.076 −0.309 0.176 0.936 21.353 84.806

0.203 0.664 0.111 0.187 0.108 10.818 95.625

0.949 c −0.344 0.922 0.821 0.043 50.917 50.917

0.016 −0.127 −0.067 0.413 0.985 23.254 74.171

−0.219 0.930 −0.293 −0.255 −0.094 21.454 95.625

0.968 −0.019 0.951 0.964 0.452 59.485 59.485

0.039 0.857 0.150 0.170 −0.726 26.295 85.780

0.232 0.513 −0.263 −0.205 0.517 13.906 99.686

0.860 0.031 0.996 0.997 0.137 54.918 54.918

0.465 −0.169 0.039 0.072 0.967 23.742 78.660

0.189 0.985 −0.050 0.003 −0.209 21.026 99.686

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Groundwater (n = 139) E. coli b pH d TDS e EC f Temperature Variance (%) Cumulative (%)

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t4:6 t4:7 t4:8 t4:9 t4:10 t4:11 t4:12 t4:13 t4:14 t4:15 t4:16 t4:17 t4:18 t4:19 t4:20 t4:21 t4:22

Factor 2

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Factor 1

Rotated component matrix

Number of samples. Escherichia coli. Bold values represent dominant parameters in each factor. Potential of hydrogen. Total dissolved solid. Electrical conductivity.

Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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Fig. 3 – Component plot in rotated space for fecal and physiochemical contaminants in ground (n = 139) and surface drinking water (n = 59).

2.4. Drinking water sources and their potential health risks

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Fig. 4 summarizes mean fecal contamination in drinking water sources collected from seven tehsils of the study area. The

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average mean fecal contamination in total well, hand pump, spring and river/stream water sources were noticed as 16.59, 11.50, 14.29 and 43.00 MPN/100 mL, respectively. The mean fecal contamination in well (dug well, bore well and tube well) water sources at tehsil Barikot, Kabal, Babozai, Charbagh, Khwazakhela, Matta and Bahrain were 56.4, 13.5, 9.88, 27.50, 13.91, 05.00 and 01.00 MPN/100 mL, respectively (Fig. 4). Similarly, in hand pump water sources the mean fecal contaminations were 22.40, 13.33, 14.00, 0.50, 6.20, 5.50 and 0.00 MPN/100 mL; in spring water sources the values were 65.00, 16.42, 20.66, 7.50, 7.25, 6.00 and 4.62 MPN/100 mL; while in river/stream drinking water sources the contamination levels were 52.00, 24.00, 28.50, 20.00, 19.00, 6.50, 5.10 at tehsil Barikot, Kabal, Babozai, Charbagh, Khwazakhela, Matta and Bahrain, respectively (Fig. 4). The maximum fecal contamination was noticed in the river/stream, well and spring

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unification of carbon dioxide and bicarbonates. The fluctuation of EC may be due to improved anthropogenic mixture of sewerage water in drinking water sources from upstream towards downstream in the study area. Likewise, the variation in TDS, temperature, color, odor and taste in groundwater sources may be associated with erosion of the loose soil and sediments from the embankments, while in surface water it might result from shortened distance between urban settlements and water sources, and upturn human activities including mining, smelting, industrial influx and agricultural activities.

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Fig. 4 – Fecal contamination (MPN/100 mL) in drinking water sources across the study area. MPN: most probable number. Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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local people infected with water borne disease were those who did not treat their drinking water before use. Generally, the adverse health impacts of drinking water contaminated with E. coli were noticed to be higher in children followed by old and young adults. The pathogenic contaminated drinking water resources significantly spread 59% of diarrhea, 15% of hepatitis, 14% of dysentery/cholera and 12% of typhoid fever in children annually (Fig. 5b); 46% of diarrhea, 20% of hepatitis, 14% of skin diseases, 11% of typhoid fever and 9% of dysentery/cholera in young adults (Fig. 5d); 52% of diarrhea, 23% of hepatitis, 12% of typhoid fever and 10% of dysentery/cholera in old age people (Fig. 5c). These waterborne diseases may be spread through pathogenic micro-organisms that are frequently transmitted to different human age groups via direct contaminated well water (86%), fetched springs water (11%) and river water (3%) intake, because these resources are noticed to be increasingly contaminated with E. coli due to intensive seepage from the nearby pit latrines and sewerage lines, and increasing discharges of toilets and municipal sewages into the river. Furthermore, these diseases may also be caused by consuming contaminated food or beverages, through contact with animals or their environment, or through person-to-person communications. Besides, poor hygiene behaviors and inadequate sanitation in public

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water resource systems at tehsil Barikot and the lowermost at tehsil Bahrain showing fecal contamination increase from upstream towards downstream of the River Swat watershed in seven tehsils of the study area (Fig. 4). Further, the questionnaire survey (including 250 questionnaires) was intended to evaluate the potential health risks in the area by using fecal contaminated water for drinking purposes. The questionnaire results revealed that there were more than 30 years old functional drinking water supply schemes. Regrettably the majority of the local communities are still using 10– 20 years old water supply systems particularly in the downstream tehsils of the study area (Appendix A Fig. S1). Based on drinking water fecal contamination, the questionnaire survey indicated high prevalence of water borne diseases including hepatitis, intestinal infections and diarrhea, dysentery, cholera, typhoid fever, jaundice, scabies and other skin diseases in local community (Appendix A Fig. S2). Moreover, the questionnaire results indicated that the overall local communities consume water from the well, hand pump, spring and river/streams for drinking purposes at the rate of 73%, 13%, 11% and 3%, respectively (Fig. 5a). In addition, the interview results showed that the local dwellers usually did not purify their drinking water with any biological, chemical or sedimentation techniques. That's why the majority of the

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Fig. 5 – Consumption rate of drinking water sources and their potential health risks in Swat Pakistan. Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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The selected fecal (E. coli) and physiochemical contaminations throughout the study area were significantly varied (p < 0.05). The physiochemical parameters including pH, temperature, turbidity, color, odor, taste, TDS and EC were within their safe limits except in a few locations, whereas the fecal (E. coli) contamination in selected drinking water sources exceeded the Pak-EPA, 2008 and WHO, 2011 permissible limits. In total 198 water samples 78.42% of the total groundwater samples were above the safe limits, while 96.70% of the total surface water samples were recorded heavily contaminated with coliform bacteria. The average mean fecal contaminations in total well, hand pump, spring and river/stream water sources were indicated as 16.59, 11.50, 14.29 and 43.00 MPN/100 mL, respectively. The maximum fecal contaminations were found in the river/stream, well and spring water sources at tehsil Barikot, and the lowermost at tehsil Bahrain showed that fecal contamination increased from upstream towards downstream in the study area. Multivariate and univariate statistical analyses revealed that downstream urbanization trend, short distance between water sources and sewerage systems/pit latrines, seepage from raw sewage deep well, domestic toilets and wastewater disposal systems, direct municipal and hotels sewage discharge, and surrounding surface runoffs were responsible for fecal and physiochemical contamination of the drinking water in the study area. The questionnaire survey evaluated the potential health risks of fecal contaminated drinking water sources consumption. The results exposed that majority of the local people using 10–20 years old water supply systems at the rate of 73% of well supply, 13% hand pump supply, 11% spring supply and 3% river/streams, respectively, which ultimately spreads high prevalence of water borne diseases including hepatitis, intestinal infections and diarrhea, dysentery, typhoid fever, jaundice, scabies and other skin diseases in children followed by old age people and young adults. Therefore, it is suggested that water from the contaminated sources should not be used for drinking purposes without proper treatment and the contaminated drinking waters sources may be replaced with raw water intake to minimize the potential health risks in the area. Moreover, the Environmental Protection Authority and other relevant institutions should routinely monitor the drinking water quality, and increase awareness among the population regarding potential health risks for various exposures to fecal and other pathogenic contamination. Moreover, the study also suggests provision of adequate and suitable sanitation and continuous health and hygiene education to the local community.

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Acknowledgments

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This study is supported by the National Key R & D Program of China (No. 2017YFC0505704), the National Natural Science

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Please cite this article as: Khan, K., et al., Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan, J. Environ. Sci. (2017), https://doi.org/10.1016/j.jes.2017.12.008

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