Safety Evaluation, Health Risk Assessment and its Source Appointment in Drinking Water Procured from Water Purification Plants of Faisalabad, Punjab, Pakistan
Saud Khalid, Muhammad Atif Randhawa, Aamir Shehzad, Shahid Masood, Muhammad Shamoon, Nida Kanwal and Rana Muhammad Adil
Faculty of Food Nutrition and Home Sciences, National Institute of Food Science & Technology, University of Agriculture, Faisalabad, Pakistan
Corresponding Author: Saud Khalid, Faculty of Food Nutrition and Home Sciences, National Institute of Food Science & Technology, University of Agriculture, Faisalabad, Pakistan
ABSTRACT
United Nations Development Program (UNDP) and Pakistan Safe Drinking Water Act (PSDWA) acknowledge adequate access to potable water as a basic necessity of human beings. To provide ample assess of adequate water to its inhabitants, Government of Pakistan (GOP) designed a project titled “Clean Drinking Water for All (CDWA)” in which it was decided to install water purification plants in each Union Council of Pakistan. Current study was designed to assess the safety status of drinking water of water purification plants of Faisalabad, Punjab, Pakistan. The study was further planned to identify potential sources of contamination and to direct policy makers for direct future investments. It concluded that factors like defective/leaked taps, presence of garbage and standing water beside sampling sites were among the common sources of microbial contamination across the study sites. On the other hand, 73% of sampling sites were classified as ‘high risk’ for microbial contamination.Among heavy metals, drinking water was found to be heavily contaminated with Pb and Fe.However, Cd wasn’t detected across the study site. Based on heavy metals concentration, chronic daily intake (CDI) and hazard quotient (HQ) was calculated. The values of CDI were in the order of Fe>Cu>Zn>Mn>Pb>Cr>Ni>Zn>Cd.The values of HQ were <1for all heavy metals in all samples indicating no health risk. Furthermore, multivariate statistical analysis like one-way ANOVA, inter-metal correlation, cluster analysis and principal component analysis results revealed that anthropogenic pollution and geochemical background were the major sources of heavy metals contamination in drinking water.
Key words: Drinking water, heavy metals, microbial contamination, risk assessment, Pakistan
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INTRODUCTION
Water is vital requisite but it has to be potable to allow secure consumption. Ground water and surface water are the two main sources of drinking water. Raw water obtained through these two sources is prone to wide variety of pollutants. These pollutants threaten all forms of life, in general. Such pollutants can be countered in two ways; either by enhancing the efficiency of water treatment plants or by improving the quality status of existing water purification plants. The first path is more technical and is opted by research institutes and universities, for instance. The second path is strategic one as it requires input of policy makers and allocation of capital by the state. Regardless of the approach undertaken, the status of water quality should be monitored periodically in order to protect public health.
Majority of population in Pakistan is exposed to polluted water which may cause a multitude of water borne diseases. WWF (2007) reported that drinking water supplied by municipalities to the public in Pakistan is mostly contaminated with pathogens or toxic chemicals. Adding to this, Bhutta et al.(2002) reported that drinking water in densely populated areas of Pakistan like Karachi, Lahore, Rawalpindi, Peshawar, Faisalabad, Qasur, Sialkot and Gujrat cannot be recommended for human consumption due to contamination caused by various anthropogenic activities. Main cause of prevalence of water borne diseases in Pakistan includes contamination of drinking water with industrial wastes as well as municipal sewage and lack of water disinfection practices cum quality monitoring of treatment plants (Hashmi et al., 2009). A study conducted in 23 major cities of Pakistan concluded that water quality of 84-89% of water sources throughout the country is below the recommended standard for drinking purpose (PCRWR, 2008). Due to lack of documentation practices and maintenance of records in hospitals, it is very difficult to quantify exactly the water borne diseases in Pakistan (Aziz, 2005). The diseases related to consumption of unsafe drinking water includes hepatitis, cholera, dysentery, cryptosporidiosis, giardiasis, and typhoid. Adding to this, all of these diseases accounts for one third of all deaths in Pakistan (WB-SCEA, 2006). The situation gets worse with water-borne diseases like hepatitis, typhoid fever, gastroenteritis, dysentery, cholera, E. coli diarrhea, rotavirus diarrhea, malaria, giardiasis and intestinal worms every year with the onset of monsoon rains in summer (July to August) due to lack of control measures and effective prevention (Qasim, 2008).
Access to safe and clean drinking water is one of the basic necessities of human beings. According to millennium development goals of United Nations Industrial Development Organization (UNIDO), half of world population should have sustainable access to safe drinking water by 2015 (UNDP, 2000). Government of Pakistan has showed its commitment to provide adequate and sustainable access of safe drinking water to people of Pakistan and to meet millennium development goals of UNDP (GOP, 2005). As per national drinking water policy, adequate access to safe and clean drinking water is a basic right of every citizen of Pakistan (GOP, 2009). To meet these targets, a program entitled “Clean Drinking Water for All (CDWA)” was designed by Ministry of Environment, Government of Pakistan under its Medium Term Development Framework. The aim of program was to notably improve water and sanitation coverage and quality. Under this project, it was decided to install water purification plants of different capacities (500/1000/2000 gallons/hour) in each Union Council of Pakistan. It was estimated that one purification plant would serve 2-20% of each Union Council’s population, which on average have 20,000 inhabitants. The program generated criticism later-on. It was argued that due to lack of communication and ill planning, the program has failed to achieve its objectives of improving water quality status of the country by installing water treatment facilities, country-wide. Under CDWA project, it was decided to install 6,584 water treatment plants all across Pakistan. However, only 1,139 water purification plants are installed so far all across Pakistan (Anonymous, 2011). Keeping in view the generated criticism, current study is designed to assess the status of existing water purification plants of Faisalabad, Punjab, Pakistan. It is feared that level of heavy metals in drinking water might reach alarming level owing to industrial significance of the study area. Therefore, the study aims at determining concentration of heavy metals in drinking water and its potential health risk assessment. Multivariate statistical analysis and risk priority matrix is used to identify sources of heavy metals and microbial contamination respectively, as well as to identify priorities for policy makers for direct future investments in water purification plants of Faisalabad, Punjab, Pakistan.
MATERIALS AND METHODS
Study area description
Safety assessment of water purification plants covers the inspection of those plants that are installed by Government of Pakistan for the well being of inhabitants of Faisalabad. Formerly known as Layellpur, it is the third largest city of Pakistan and is the second largest city of province Punjab (Fig. 1). Owing to its industrial importance, it is also known as Manchester of Pakistan. Faisalabad was acknowledged as City District in 2005 and was divided into 8 autonomous twons; including Lyallpur Town, Madina Town, Iqbal Town, Jinnah Town, Chak Jhumrah Town, Jaranwala Town, Samundri Town and Tandlianwala Town. The total number of water purification plants installed by government in Faisalabad are 37 out of which, only 21 are functional. The number of functional water purification plants in Jinnah Town, Madina Town, Iqbal Town and Layellpur Town are 11, 6, 2 and 1 respectively. There are two water purification plants installed in Chak Jhumra Town, both of which are non-functional. Moreover, no water purification plant is installed in Samundri Town, Jaranwala Town and Tandlianwala Town.
Survey design
Safety assessment of water purification plants covers the inspection of those plants that are installed by Government of Pakistan for the well being of inhabitants of Faisalabad. While procuring samples, care is taken to analyze no less than 50% of functional water purification plants from each Town of Faisalabad. For this purpose, 6 samples were procured from Jinnah Town, 3 from Madina Town and 1 each from Layellpur-Town as-well-as from Iqbal- Town. Each sample was encoded using two English letters (WS- stands for Water Sample) and a third numeric letter. The numeric letter is specific for each water purification plant. Number of water samples that were procured from each town are mentioned in Table 1.
Sampling plan
Water samples for physicochemical analysis were collected in PET bottles of 750 mL capacities. Un-rusted taps were selected for collection of water samples. These taps were properly cleaned and allowed to flow for a few minutes before collecting the samples. Before collecting the samples, the bottles were washed properly and rinsed thoroughly several times first with water and then with distilled water.
Sanitary inspection risk survey (SIRS)
A questionnaire was adopted, by following WHO guidelines (WHO, 2012), to carry-out sanitary inspection risk survey of selected water purification plants. The questionnaire examines physical well being of each water purification plant. It asks 10 questions; the answer to each question may either be “yes” or “no”. Answering the question with ‘yes’ shows the presence of risk and vice versa. Higher number of positive answers shows higher risk. This qualitative data was then converted into quantitative one, based on the findings of risk score. It also enlightens how to summarize the risk score from the findings of sanitary inspection risk survey. The findings of SIRS are beneficial in pointing out the sources of microbial contamination in procured drinking water samples.
Physico-chemical and microbial analysis
Total coliform count
Totalcoliform in the drinking water samples were counted by using Galaxy, 230 colony counter usingMost Probable Number method (MPN) as proposed by AOAC (2005).
Water characteristics
By using digital pH meter (Inolab WTW Series 720), benchtop meter (CON-700, EUTECH) and portable turbidimeter (TN-100/T-100, EUTECH); the pH, electrical conductivity (EC), total dissolved solids (TDS) and turbidity were determined following APHA guidelines (APHA, 1992).
Toxic metals
Procured water samples were digested initially (Prapaisiri et al., 1988). The digested samples were then passed through Atomic Absorption Spectrophotometer (Hitachi Polarized Zeeman AAS, Z-8200, Japan) following the conditions as described by Horwitz, 2000. Following heavy metals were analyzed; Cadmium (Cd), Copper (Cu), Chromium (Cr), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb) and Zinc (Zn).Calibrated standards were prepared from the commercially available stock solution (Applichem®) in the form of an aqueous solution (1000 ppm). Highly purified de-ionized water was used for the preparation of working standards. All the glass apparatus used throughout the process of analytical work were immersed in 8N HNO3 overnight and washed with several changes of de-ionized water prior to use.
Human health risk assessment
Chronic daily intake (CDI) indices
The CDI through water ingestion was calculated according to the modified equation from (USEPA, 2005).
CDI = (C x DI) / BW
where, C, DI and BW represent the concentration of heavy metals in water (mg/L), average daily intake rate (2 L/day) and body weight (72 kg), respectively (Muhammad et al., 2010).
Hazard quotient (HQ) indices
The hazard quotient for non-carcinogenic risk can be calculated by the following equation (USEPA, 2005):
HQ = CDI / RfD
where, according to USEPA database the oral toxicity reference dose value (RfD) is 5.0E−04, 1.5, 3.7E−02, 1.4E−01, 2.0E−02, 3.6E−02, 3.0E−01 mg/kg-day for Cd, Cr, Cu, Mn, Ni, Pb and Zn, respectively (USEPA, 2005). The exposed population is assumed to be safe when HQ<1 (Khan et al., 2008).
Source appointment and statistical analysis
Descriptive statistics is calculated by using Excel 2007 (Microsoft Office). The univariate and multivariate statistical analysis such as one-way ANOVA procedure, inter-metal correlation, cluster analysis (CA) and principle component analysis (PCA) are performed by using the SPSS software ver. 17.
RESULTS AND DISCUSSION
Sanitary inspection risk survey (SIRS)
SIRS is a component of water safety plan for community management as it provides an overview of likely threats to water quality and is an effective tool for rapid assessment of drinking water quality (WHO, 2012). The findings of sanitary inspection risk survey (Table 2) highlights that almost all the taps installed in government owned water purification plants of Faisalabad are defective. Moreover, roads and/or garbage accompanies all of the water purification plants of Faisalabad. Both of these factors are regarded as a highest source of contamination in these purification plants. It is further noted that in 90% of water purification plants of Faisalabad, there is faulty drainage channel. Such faulty drainage channels allow water to collect around the sampling sites. When water collects in the surroundings areas, garbage accumulates while flies gather across the sampling sites. The presence of garbage and flies are the potential sources of contamination in drinking water across the sampling sites. Remaining factors including leaked pipes across sampling sites, defective concrete floor, inadequately sealed walls, access of animals to sampling sites due to defective construction and the presence of latrines beside water purification plants; holds negligible importance. Faulty tap as well as garbage and/or roads beside water purification plants are regarded as serious risk in each town of Faisalabad. However, leaked pipes, accumulation of water and the presence of flies around the sampling site are town specific problems. Leaking pipeis regarded as risk factor in Layellpur Town only where it appeared as risk factor in all of the assessed water purification plants. Collection of water around the sampling sites is emerged as a risk factor in Jinnah Town as well as Iqbal Town. The presence of flies around the sampling sites is problem specific to the locality of Madina Town and Jinnah Town. Accumulation of water around the sampling sites is the most serious problem and it leads to presence of other risk factors in the sampling sites. For example, accumulation of water is always accompanied with garbage accumulation as well as presence of flies around the sampling sites as it is evident from the sanitary inspection of Jinnah Town.
Physico-chemical and microbial analysis
Summary of physico-chemical and microbial parameters is summarized in Table 3a. The compliance for these parameters with WHO standards on drinking water quality is given in Table 3b.The detailed interpretation of these parameters is given below:
Total coliform count
The results of present study indicate that coliform is present in more than 80% of procured water samples. The order of coliform count per 100mL is as following; Iqbal-town(13)>Jinnah-town(11)>Madin-town(10.7)>Layellpur-town(0).Coliform isn’t detected only in 2 samples, one sample each from Jinnah town as-well-as from Layellpur town. Coliform was detected in all the remaining samples.
Water characteristics
pH
The pH of Jinnah town ranged from 6.7-7.9 with a mean value of 7.4. Range of pH values in Layellpur town, Iqbal town and Madina town is 6.8-7.0, 7.3-7.5 and 6.6-7.3, respectively. Mean value for pH in these towns is 6.9, 7.4 and 7, respectively. Highest pH is observed in Jinnah town and Iqbal town (7.4), while the lowest pH is observed in Layellpur town (6.9). However, pH in all towns of Faisalabad is in compliance with recommended value of pH as proposed by WHO (1998).
Total dissolved solids (TDS)
Range of total dissolved solids in water samples procured from Jinnah town, Layellpur town, Madina town and Iqbal town is 7.1-131, 150-160, 5.6-15.6 and 7.3-159 ppm, with the mean value of 60.5, 155, 10.6 and 62.1 ppm, respectively. Observed value of TDS observed in water sample is in following order; Layellpur-town>Madina-town>Jinnah-town>Iqbal-town. However, all the procured water samples showed cent percent compliance with recommended value of TDS as proposed by WHO(1998).
Electrical conductance (EC)
Highest electrical conductance is observed in Layellpur town (316 µS/cm) while the lowest is observed in Madina town (1.52 µS/cm). The order of electrical conductance in terms of its mean values is as following; Layellpur-town(314µS/cm)>Jinnah-town(116.97µS/cm)>Madina-town(105.7µS/cm)>Iqbal-town(20.3µS/cm). Out of total procured samples, 73% samples are in compliance with recommended value of EC as set by WHO(1998).
Turbidity
Observed range of turbidity is 0.08-0.45, 0.0-0.1, 0.37-0.47 and 0.21-0.77 NTU for Jinnah town, Layellpur town, Iqbal town and Madina town, respectively. The order of turbidity in terms of its mean value is as following; Madina-town(0.43NTU)>Iqbal-town(0.42NTU)>Jinnah-town(0.25NTU)>Layellpur-town(0.05NTU). Turbidity value of all the samples lie within the recommended values of WHO & Pak-EPA standard on drinking water quality.
Toxic metals
Cadmium (Cd)
Toxicity of Cadmium is of great concern to humans. However, Cadmium wasn’t detected in any of the procured sample in current investigation. Mahmood & Maqbool in 2006 procured ground water samples from Chakera, Faisalabad and found none of the sample to be contaminated with Cadmium. Similarly, Ullah et al., (2009) procured ground water from different spots of Sialkot, Punjab and found none of the sample to be contaminated with Cadmium.
Chromium (Cr)
In current investigation, Chromium is detected in all of the procured water samples. Only, 45% of the samples showed concentration of Chromium within permissible limits as set by WHO and Pak-EPA. Highest Cr is observed in Madina town i.e. 0.08 ppm. The order of Chromium detection is in following order; Layellpur-town(0.053ppm)>Jinnah-town(0.05ppm)>Iqbal-town(0.04ppm)>Madina-town(0.038ppm).
Copper (Cu)
In current investigation, both highest and lowest concentration of Cu is observed in Iqbal town i.e. 0.58 and 0.1 ppm, respectively. The order of Copper detection in study area is Jinnah-town(0.37ppm)>Madina-town(0.30ppm)>Layellpur-town(0.27ppm)>Iqbal-town(0.26ppm). However, all the samples are in compliance with recommended value of Copper as set by WHO and Pak-EPA.
Iron (Fe)
Highest concentration of Iron is observed in Jinnah town (1.64 ppm) while the lowest is observed in Madina town (0.80 ppm). The order of iron concentration in study area is as follow; Layellpur-town(1.23ppm)>Jinnah-town(1.20ppm)>Madina-town(1.12ppm)>Iqbal-town(1.05ppm).