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Human and Ecological Risk Assessment: An International Journal Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/bher20

Arsenic and Heavy Metal Concentrations in Drinking Water in Pakistan and Risk Assessment; A Case Study a

a

b

Sardar Khan , Irfan Ali Shah , Said Muhammad & Riffat Naseem Malik a

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Department of Environmental Sciences, University of Peshawar, Pakistan

b

Department of Earth Sciences, COMSATS Institute of Information Technology, Abbottabad, Pakistan c

Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-I-Azam University, Islamabad, Pakistan Accepted author version posted online: 08 Aug 2014.

To cite this article: Sardar Khan, Irfan Ali Shah, Said Muhammad & Riffat Naseem Malik (2014): Arsenic and Heavy Metal Concentrations in Drinking Water in Pakistan and Risk Assessment; A Case Study, Human and Ecological Risk Assessment: An International Journal, DOI: 10.1080/10807039.2014.950925 To link to this article: http://dx.doi.org/10.1080/10807039.2014.950925

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ACCEPTED MANUSCRIPT Arsenic and Heavy Metal Concentrations in Drinking Water in Pakistan and Risk Assessment; A Case Study

Sardar Khan,1 Irfan Ali Shah,1 Said Muhammad,2 and Riffat Naseem Malik3

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1

Department of Environmental Sciences, University of Peshawar, Pakistan; 2Department of Earth

Sciences, 3

COMSATS

Institute

of

Information

Technology,

Abbottabad,

Pakistan;

Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences,

Faculty of Biological Sciences, Quaid-I-Azam University, Islamabad, Pakistan

Address correspondence to Said Muhammad, Department of Earth Sciences, COMSATS Institute

of

Information

Technology,

Abbottabad,

Pakistan;

E-mail:

[email protected]; [email protected]

Running Head: Arsenic and Heavy Health Risk Assessment via Drinking Water

Received 8 March 2014; revised manuscript accepted 28 July 2014

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ACCEPTED MANUSCRIPT ABSTRACT The present study was performed to assess drinking water quality and potential health risk in the Nowshera District, Khyber Pakhtunkhwa, Pakistan. For this purpose drinking water samples were collected from local available sources and analyzed for physico-chemical

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characteristics, As, and heavy metals. Results revealed high levels of toxic heavy metals such as Cr, Ni, Pb, Cd, and As contaminations in the drinking water. Results were evaluated for chronic risk including average daily intake (ADI) and hazard quotient (HQ). Among heavy metals the hazard quotient (HQ) values were highest for Cd (5.80) and As (2.00). Therefore, populations in the study area may be at low level of chronic toxicity and carcinogenic risk. Statistical analyses showed that contribution of different drinking water sources to the mean contaminant levels in the study area was insignificant (p = 0.53). Correlation analysis further revealed that anthropogenic activities were the main sources of contamination rather than geogenic. This study strongly recommends the treatment of urban and industrial wastewater in the vicinity of the study area and provision of safe drinking water.

Key Words: drinking water, hazard quotient, average daily intake, cancer risk, statistical analyses, Nowshera District

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ACCEPTED MANUSCRIPT INTRODUCTION Drinking water contaminations have both natural (ore deposits, rocks weathering, and erosion) and anthropogenic (industries, mining, agriculture activities, and wastewater) origins (Muhammad et al. 2010; Khan et al. 2013; Li et al. 2014). Among contaminants the heavy

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metals are of global concern, which find their ways into water and food, impairing their quality and cause toxicity (Shah et al. 2012; Spayd et al. 2012; Hu et al. 2014). Among metals, Na, Ca, Mg, Zn, Co, Fe, and copper (Cu are essential and required at certain concentrations for normal body function and growth. However, others such as As, Cd, Hg, Ni, and Pb are non-essentials or toxic metals and causing numerous human health risks after ingestion (Muhammad et al. 2010, 2011). Toxic effects of these metals include abdominal pain, headache, irritability, blood pressure, kidney damage, nerve damages, skeletal damage, cancer, and affects intellectual functions (Khan et al. 2013). Characteristically, heavy metals are mostly carcinogenic in nature but their toxicity and targeted organs vary from metal to metal and also depend on the ingested amount, body immunity of the individual, and exposure duration (Goyer et al. 2004). Heavy metals enter into the human body through several pathways. However, oral ingestion, especially through drinking water, is one of the major sources for human exposure (Spayd et al. 2012; Khan et al. 2013). Humans need drinking water for sustaining life and social prosperity. Provision of clean water supplies is a high priority issue for safe guarding a population’s health (Simeonov et al. 2002). Clean drinking water and its adequate supply is a key factor contributing to decreased mortality and morbidity and improved economic development in the developing countries (Koc 2010). Therefore, human health risk assessment through drinking water consumption has become

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ACCEPTED MANUSCRIPT the prime focus of environmental researchers globally (Spayd et al. 2012). Being a developing country, Pakistan is facing a serious crisis in the supply of clean and safe portable water in its urban and rural areas. In the past, few studies have been reported on drinking water contaminations in the northern region of Pakistan (Muhammad et al. 2010, 2011; Shah et al.

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2012; Khan et al. 2013). Although, the Nowshera District hosts a population of more than 1.2 million, no research has been carried out on drinking water quality and it potential health risk. Therefore, this study aimed to identify the sources of drinking water contaminations and their potential health risk assessment in the selected district.

METHODS AND MATERIALS Study Area The Nowshera District is located along the banks of the Kabul River and lies between 33º-41` to 34º-10` N latitudes and 71º-39` to 72º-16` E longitudes, with a total area of 1748 km2 (Figure 1). It is bounded on the east by the Attock District of Punjab Province, on the west by Peshawar and on the northwest side by Charsadda, while on the northern side by the Mardan and Swabi Districts and on the south by the Kohat District. The district is cold (4ºC) in winter and very warm (43ºC) in the summer, receiving an annual precipitation of 600 mm. Generally, depth in water tables varies from 13--50 meters. The main professions of the local residents are agriculture, business and jobs in government institute, or the Amangarh Industrial Estate (AIE). The AIE hosts a number of paper, textile, ceramics, tanneries, and ghee industries. The Kabul

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ACCEPTED MANUSCRIPT River enters this district at its western side and runs through the plain and joins the Indus River at a kund near Khairabad (DCR 1998).

Water Samplings and Analyses

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Inhabitants of the Nowshera District are using tube wells, bore wells, dug wells, and hand pumps as sources of water for drinking purposes. The district was classified into 39 sampling sites and each site into three spots (Figure 1). From each spot, water was collected in two plastic bottles. Basic parameters such as pH and electrical conductivity (EC) were measured on the spot using water quality checker U-10 Horriba-Japan. The location of each sampling site was noted using a global positional system (GPS). Water of one bottle was acidified at each sampling spot for As and heavy metal analyses, while another bottle was non-acidified and tested for anions including nitrate (NO3), sulphate (SO4), and chloride (Cl). Collected samples were transported and stored in the dark at 4ºC for further analyses (APHA 2005). Nitrate, SO4, and Cl were measured in non-acidified samples by the titration method adopted from the American Public Health Association (APHA 2005). Light metals (Na, K, Ca, and Mg) and heavy metals (Pb, Cu, Cr, Ni, Cd, and Zn) were measured using a graphite atomic absorption spectrophotometer (Perkin Elmer, AAS-PEA-700), while As concentrations were measured using a mercury hydride system (MHS).

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ACCEPTED MANUSCRIPT Analyses were performed in triplicate. Reproducibility was found to be at 95% confidence level. Therefore, mean values of samples were used for results interpretation. Reliability and reproducibility of analyses were checked by analyzing blank and known standards after every 10 samples. Chemicals (acids and reagents) used in samples’ analyses were

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of analytical grade and purchased from MERCK & Co., Inc. All analyses were performed in the geochemistry laboratory of the National Centre of Excellence in Geology (NCEG), University of Peshawar, Pakistan.

Potential Risk Assessment Exposure assessment For exposure assessment of the study area, the average daily intake (ADI) of metals through drinking consumptions is calculated according to the equation adopted from the U.S. Environmental Protection Agency (USEPA 1998) and Shah et al. (2012). ADI = CW x IR x EF x ED/BW x AT

(1)

where CW is the concentration of metals in water (mg/L), EF is the exposure frequency (365 days/year), IR is the ingestion rate of water (L/day), ED is exposure duration (30 years), BW is bodyweight (60 kg), and AT is averaging time, i.e., 365 days/year × ED for non-carcinogens and 365 days/year × 70 years for carcinogens (ASTDR 2008; WHO 2011; Shah et al. 2012).

Risk assessment Chronic risk level was calculated using the following equation adopted from USEPA (1998) and Muhammad et al. (2011).

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ACCEPTED MANUSCRIPT HQ = ADI/RfD

(2)

where HQ is the hazard quotient and RfD is the reference dose (mg/kg-day). The carcinogenic risk level was calculated using following formula: CR = ADI x CF

(3)

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where CR is the cancer risk and CSF is the cancer slope factor (mg/kg-day-1). The CSF value of As is 1.5 mg kg-1 day-1 as adopted from USEPA (2005) and Muhammad et al. (2010).

Statistical analyses Data were analyzed statistically for means, range, standard deviation, one-way Analysis of Variance (ANOVA), and Pearson’s correlation using MS Excel (2007) and SPSS 18 (SPSS Inc., Chicago, IL, USA).

RESULTS AND DISCUSSION Physico-chemical Parameters Summarized in Table S1 (see Supplemental Material1) are the concentrations of physicochemical parameters in drinking water of the Nowshera District. The minimum (5.7) value of pH was found in tube well water at Umaray, with maximum (7.3) in dug wells at the Nowshera cantonment and hand pump at Pabbi. The drinking water of the study area was slightly acidic. Among water quality parameters, pH is one of the important indicators of contamination level in an aquatic system (Jonnalagadda and Mhere 2001) and affects water quality (viz., pathogens 1

Supplemental Material is available on request from the publisher.

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ACCEPTED MANUSCRIPT survival and metal solubility). EC values were observed lowest (276.0 µS/cm) in tube well water at Manahi, while highest (2400.0 µS/cm) in tube well water at Umaray. The values of pH and EC were observed to be within the safe drinking water guidelines of Pak EPA (2008) and WHO (2011). However, 12% of sampling sites surpassed the safe limit of EC. Tube well water showed

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higher EC values as compared to other sources of drinking water. The EC qualitatively estimates the contamination level in water (viz., ionized species and inorganic dissolved solids) (Jonnalagadda and Mhere 2001). Water chemistry is subjective to bed rock and contaminant sources in the vicinity of an area (Muhammad et al. 2010; Shah et al. 2012). Dissolution of minerals in rain water is mainly responsible for the metal contents in groundwater. These metals’ concentrations are affected by the mineralogy of the aquifer and water residence time. As a result deeper groundwater can feel prominent changes in elemental composition with increasing residence time (Edmunds et al. 1987; Shah et al. 2012). Chloride concentrations were found lowermost (21.0 mg/L) in tube well water at Akora Khattak, while uppermost (200.0 mg/L) in dug well water at Risalpur. Similarly, NO3 values were found minimum (1.5 mg/L) in hand pump water at Adamzai, while maximum (55.0 mg/L) in tube well water at Hisartang village. This highest concentration of NO3 in tube well water may be attributed to extensive agriculture practices in Hisartang village and surrounding. SO4 concentrations were observed highest (68.0 mg/L) in bore well water at Ziarat KaKa Sahib, while lowest (5.0) in Kheshgi, Risalpur, Shekhan, etc. Highest SO4 concentrations in bore well water at Ziarat KaKa Sahib may be attributed to sulphide mineralization and fertilizer based agriculture practices in the vicinity. The concentrations of Cl,

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ACCEPTED MANUSCRIPT SO4 and NO3 were found to be within the drinking water guidelines suggested by domestic and international organizations such as Pak EPA (2008) and WHO (2011) (Table S1). Sodium concentrations ranged from 7.0--50.2 mg/L (Table S1). Highest (50.2 mg/L) Na concentrations were found in dug well water at Kanra Khel. Similarly, K concentrations ranged

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from 0.7--14.2 mg/L (Table S1). Maximum (14.2 mg/L) K concentrations were noted in bore well water at Badrashi. The concentrations of Ca ranged from 9.4--269.8 mg/L (Table S1). Uppermost Ca concentrations were noted in dug well water at Rashakai. Similarly, Mg concentrations ranged from 3.7--74.2 mg/L (Table S1). Highest (74.2 mg/L) Mg concentrations were observed in bore well water at the Shaidu village. Shallow water (dug wells and hand pump) sources showed highest concentrations of Na, K, Ca, and Mg as compared to deep water sources. The concentrations of Na, K, Ca, and Mg were found to be within the safe drinking water guidelines of Pak EPA (2008) and WHO (2011). However, 15% and 8% of sampling sites showed anomalies from the limits of Ca and Mg, respectively. Muhammad et al. (2010) reported that light metal such as Na, K, Ca, and Mg are essential elements required for human and their deficiency may cause health problem (e.g., low blood pressure, hypertension, depression, fatigue, dehydration, muscle weakness, bladder weakness, kidney problem, and heart problems). Copper concentrations ranged from