Drinking water quality of various sources in Peshawar, Mardan, Kohat and Swat districts of Khyber Pakhtunkhwa province, Pakistan

The present study involves the chemical and bacteriological analysis of water from different sources i.e., bore, wells, bottle, and tap, from Peshawar, Mardan, Swat and Kohat districts of Khyber Pakhtunkhwa (KP) province, Pakistan. From each district, 50 water samples (10 samples from each source), regardless of urban and rural status, were collected from these sources and analysed for sulphates, nitrates, nitrites, chlorides, total soluble solids and coliforms ( E. coli ). Results indicated that majority of the water sources had unacceptable E. coli count i.e.> 34 CFU/100mL. E. coli positive samples were high in Mardan District, followed by Kohat, Swat and Peshawar district. Besides this, the some water sources were also chemically contaminated by different inorganic fertilizers (nitrates/nitrites of sodium, potassium) but under safe levels whereas agricultural and industrial wastes (chloride and sulphate compounds) were in unsafe range. Among all districts, the water quality was found comparatively more deteriorated in Kohat and Mardan districts than Peshawar and Swat districts. Such chemically and bacteriologically unfit water sources for drinking and can cause human health problems.

comparable less security risks, and considerable place for migrating war stricken populations.

Sampling
For both bacteriological and chemical analysis, water samples (n=200) were collected in 50 mL sterile polyethylene bottles from 5 different sources i.e. bottles, wells, bore (115-380 feet), taps, and hand-pumps in a sterile manner (Ahmad et al., 2012b;Gwimbi, 2011). 50 samples were collected from each district. The purposive sampling was done to collect all the samples from each district. These samples were immediately stored at a temperature between 0 to 4 °C before processing (Anwar et al., 2010).

Microbiological analysis
For microbiological analyses, previously mentioned methods were followed after little modification (Akeju and Awojobi, 2015). Lauryl Triptose broth was used as a medium in presumptive coliform test (Ali et al., 2011;Anwar et al., 2010). Three sets of tubes were inoculated with 10 mL, 1 mL and 0.1 mL of each water sample. The tubes were incubated at 37 °C to 44 °C for 24-48 hours and examined for acid and gas production. Following this presumptive coliform test, total coliform confirmatory test was performed using Brilliant Green Lactose Bile broth. For total coliform, these inoculated tubes were incubated at 37 °C for 24-48 hours. For faecal coliform, these tubes were incubated at 44 °C and kept under observation for gas production. After faecal coliform confirmation, Eosin Methylene Blue (EMB) agar plates were used for detection of E. coli. These EMB plates were streaked by a loop dipped in the broth from each positive tube and checked for bacterial presence (Ali et al., 2011;Anwar et al., 2010).

Statistical analysis
Basic descriptive statistical analysis was performed to interpret the maximum and minimum values in categories of ions and bacteria found in different districts and different sources by utilizing GraphPad Prism v6.0 for windows (GraphPad Software, Inc., San Diego, CA). AICcmodavg package of R-language was utilized in order to compare different groups using two way ANOVA test and Tukey HSD post -hoc test (p-value <0.05).

Introduction
Contaminated water is known as one of the major health risks in Pakistan (Ahmad et al., 2012a). Both chemical ions and microbial contamination are considered as the culprit. Common bacterial contaminants include E. coli, Salmonella, Shigella, and Campylobacter jejuni. On the other hand, viral contaminants like norovirus, rotavirus, enteroviruses, hepatitis causing viruses and parasitic agents e.g. Giardia, Cryptosporidium and Microsporidia etc. are mostly involved in water contamination (Leclerc et al., 2002). Among all these infectious contaminants, Coliform i.e. E. coli is considered as most prevalent infectious agent that is highly associated with the human and animal intestinal infections (Nkere et al., 2011).
In addition to microbial contamination, anions and cations in high quantity such as nitrates, nitrites, sulphates, and chlorides also cause serious threats to human and animal health. Nitrate and nitrite affect non-breastfed infants and cause 'blue baby syndrome' in them. In addition to this, it has no taste, colour and smell and can only be detected through chemical tests. According to World Health Organization (WHO) and Pakistan Research Council in Water Resources (PCRWR), nitrite and nitrate levels greater than 1-3 mg/L and 10-50 mg/L, respectively, can pose a risk to humans. It is gains entry through ingestion onlydrinking, cooking, teeth brushing (Rashid et al., 2018). On the other hand, chloride ions are potential cause of bad taste and hypertension because of its presence along with sodium ions. Addition to these studied ions, presence of sulphate ions in drinking water causes a laxative effect and dehydration. Its presence in drinking water also changes in the taste. For chlorides and sulphates, WHO and PCRWR have set standard limits to 250 mg/L. In short, these ions, more than their standard limits, can cause major impact on human health (Feldman et al., 2007).
Pakistan is considered among those countries that have low sanitary conditions and lack of knowledge (Anwar et al., 2010). Among all the provinces, Khyber Pakhtunkhwa is considered as one of the most war stricken, flood affected, distant and highly impoverished area. It is reported that water-borne diseases are a huge menace for the population comprising only 47% of households with tap water and 61% with safe sanitations in Pakistan, several studies to monitor the drinking water quality have been carried out, but the remote, rugged and poverty stricken mountainous areas remained least monitored or almost neglected. After observing this situation, the present study has been conducted to investigate the bacteriological and chemical analysis of drinking water in most important districts i.e., Peshawar, Mardan, Kohat and Swat districts of Khyber Pakhtunkhwa (KP) Pakistan.

Materials and Methods
As mentioned earlier, Khyber Pakhtunkhwa is considered as one of the most war stricken area. Additionally, districts included in this study, such as Peshawar, Kohat, Swat and Mardan, were selected on the basis of high population,

Microbiological analysis
The results of bacteriological analysis for all districts are shown in Figure 1. This study analysed water from different sources present in each district and were found contaminated with bacteria, both total coliforms and E. coli (Table 1). The water samples from all the districts resulted in the varying trends of bacterial contamination. In Peshawar district, of 50 samples, 22 (44%) samples were positive for total coliform and 14were positive for E. coli. The highest value of bacterial contamination was recorded in bore water/hand-pumps water 6 (60%), tap water and hotel water followed by well water 4 (40%) and bottle water 0%. In Mardan district, among total 50 samples, 24 (48%) and 22 (44%) samples were positive for faecal coliform and E. coli respectively. The bacterial contamination was recorded as highest 8 (80%) in well water and hotel water. In Kohat district, 34 (68%) positive samples for faecal coliform and 22 (44%) positive samples for E. coli were identified in 50 samples. The highest bacterial contamination was observed in tap water 8 (80%) followed by hotel water 6 (60%), bore water 6 (60%), well water 4 (40%) and bottle water 2 (20%). In Swat district, 18 (36%) faecal coliform positive samples and 14 (28%) E. coli positive samples were identified. The bore water was revealed to be highly contaminated with 6 (60%) contaminated samples whereas well water, tap water and hotel water were comparatively less contaminated i.e. 4 (40%).
In present study, faecal coliform count (> 34 cfu/100mL) was far above the accepted WHO standard i.e., 0 cfu/100 mL in drinking water (WHO, 2004). These results indicate the presence of contact between human and animal wastes or possible mixing of drinking water with sewerage water. From bottle water, in all the districts, least bacterial counts were observed. These results were in fully agreement with the reports of Pakistan Research Council in Water Resources (PCRWR) (PCRWR, 2012). On the other hand,  samples from hotels, taps and bore water were observed as highly contaminated that is similar to the previous studies (Ahad et al., 2000;Ali et al., 2011;Anwar et al., 2010). Pipelines are potential source of bacterial contamination as the distribution network of water supply comes in contact with waste-water and faeces (Moe and Rheingans, 2006;Younas et al., 2016;Rashid et al., 2021).
to drink according to PSQCA and WHO standards i.e., 250 mg/L (Figure 2a). When comparing with other water sources across the districts, higher concentrations were observed in well water and hotel water whereas bore water had least sulphate contents. For water of the Khyber Pakhtunkhwa, the high values of sulphates were reported from hotel water and well water sources (Hussain et al., 2012;Khan et al., 2005). In all the cases, water of Khyber

Chemical analysis
The highest concentration of sulphate was recorded in well water from district Peshawar with 233.2 ± 62.88 mg/L (150-305 mg/L) ions whereas least concentration of 36.2 ± 22.01 mg/L (8-65 mg/L) ions was recorded in Bore water of district Mardan (Figure 2). The sulphate content of all water samples from these districts was permissible has been reported to produce hypertension (WHO, 2004). Possible source may be due to leaching of soil minerals, increasing salinity, washing of utensils containing pesticides and nearby restaurants (Rashid et al., 2018).
TSS level was significantly high i.e. 9 ± 2.70 mg/L in well water of Kohat district and the least value i.e. 2.2 ± 0.58 mg/L was recorded in bottled water of Peshawar district. The trend of TSS level was higher (> 7 mg/L) in well water of all districts followed by hotel water (5-7 mg/L). Bore water, bottle water and tap water were present in acceptable TSS level limits (< 5mg/L) (Figure 2e). On the other hand, allowable standard values of Total Soluble Solid (TSS) range below 5 mg/L (WHO, 2004). Well water sources across the districts were found with high TSS level (5.75-9 mg/L) indicating that well water is being exposed to certain contaminated sources. These results are in accordance with Khan et al. (2012a).
Among the districts, Well water from Kohat had the highest value which is completely in agreement with previous study (Azizullah et al., 2011;Khan et al., 2013). TSS content of water causes salinity or cloudy appearance and mainly occurs due to carbonates and bi-carbonates. These suspended soluble compounds are possibly released from the sedimentary rocks, industrial wastes and sewerage pipelines (Azizullah et al., 2011).Among the sources, hotel and wells near to sewage areas, canals, common drinking places of animals, and factory areaswere found more contaminated as compare to others.

Conclusion
This study concludes that water of KPK province is not chemically and microbiologically fit for drinking especially from unprotected sources that possess microbial contamination i.e., wells and hotels. When drinking water, people must ensure the purity of water otherwise results could be drastic. The microbial contamination can be prevented by taking certain precautionary measures. For family and children in home, Filtered and Boiled water should be used as there is risk of contamination of tap water. When in journey, bottle water is a good option. We recommend that water surveys must be continued to detect baseline data and different levels of other ions and heavy metals. This will be helpful in determining the future needs and tailoring of future policies.