http://journal.uir.ac.id/index.php/JGEET E-ISSN : 2541-5794 P-ISSN : 2503-216X Journal of Geoscience, Engineering, Environment, and Technology Vol 03 No 04 2018 RESEARCH ARTICLE Groundwater Quality Assessment for Drinking Purpose in Gulistan-e-Johar Town, Karachi, Pakistan Adnan Khan 1,*, Muhammad Akif Khan1 1 Department of Geology, University of Karachi, Pakistan * Corresponding author : [email protected] Received: August 29, 2018; Accepted: November 1, 2018. DOI: 10.24273/jgeet.2018.3.4.2086 Abstract The main objective of present study is to evaluate the groundwater quality of Gulistan-e-Johar town for drinking. For this purpose, groundwater samples (n=18) through electrically pumped wells were collected from shallow aquifers (mean depth = 36 m). Collected samples were subjected to determine the physical characters (TDS, pH, temperature), major (Na, K, Ca, Mg, Cl, SO4, HCO3, and NO3) and minor ions (Fe, Mn and F). Data reveal very high content of TDS (mean: 2862 mg/L) coupled with elevated concentration of Na (mean: 974.6 mg/L), Cl (mean: 545.3mg/L), SO4 (mean: 600mg/L), Mn (mean: 0.04 mg/L) and F (mean: 1.7 mg/L). The results indicated that groundwater of Gulistan-e-Johar is not suitable for drinking purpose and may lead to dangerous health impacts. The WQI value of groundwater is found to be 183 which is also endorsing that groundwater of Gulistan-e-Johar is unfit for drinking purpose. Keywords: Groundwater quality, physicochemical parameters, water quality index (WQI), Gulistan-e-Johar. contribute to an increase in concentration of different 1. Introduction pollutants in groundwater (Reghunath et al., 2002). Water is one of the vital constituents for all lives Gulistan-e-Johar is newly developed residential among other blessings. It can be obtained by surface area with no industrial activity. Army cantonment sources including rivers, canals, lakes, streams etc. and areas and air force base coupled with central ordinance underground sources like groundwater abstraction depot surround the area. upper-middle class with from wells and borehole (McMurry and Fay, 2004). satisfactory literacy rate live in this part of Karachi city. More than half of the population depends on This town covers an area of about 10.84 sq. km which groundwater for survival worldwide (UNESCO, 1992). serves as the largest centre of flat projects in Karachi. Water resources are decreasing as the population is There is a rapid decline in municipally supplied water increasing day by day. It is widely believed that about since last couple of decades. As a result, switch over to 80% of all the diseases are water borne (WHO, 2011). groundwater is frequent to meet the domestic needs. The attributes of water depend on its chemical Moreover, people are heavily dependent on the bottled composition which is controlled by natural and water for drinking purpose which is mined from anthropogenic activities in context of measurable groundwater of study area and processed in the quantities (Kumar, 1997). Thus, the ability to forecast Reverse Osmosis (R.O) plants. Despite of switch over to the hazards and pollution resulting from the groundwater for drinking and installation of large groundwater flow has dynamic importance for the number of RO plants no study has been carried so far to precise evaluation (Khan et al., 2017). screen the quality of groundwater in the study area. Karachi is the largest and densely populated city of Therefore, present study is pilot evaluation of Pakistan where water is mainly supplied through groundwater in study area by determining the pipelines. Besides, groundwater is the other major physicochemical parameters of collected water source for domestic use. Due to rapid population samples. growth and up-country migration the balance between 2. Geology of Study Area water demand and supply has been disturbed. As a result, people are switching over to exploit Geologically, Gulistan e Johar town rests on Gaj groundwater for their needs. The over abstraction of Formation of Miocene age which in turn is comprised groundwater depletes water table and accelerates the of four members. Gulistan-e-Johar member is the contaminant transport from the land to the aquifer youngest among all members ofGaj Formation (Fig. 2). (Shah and Roy, 2002) which ultimately pollute the This member is spread over the study area where it aquifers. Domestic sewage and industrial effluent shows lihtic character as variegated series of shallow marine clastics followed by fossiliferous limestones. 200 Khan, A & Khan, M.A./ JGEET Vol 03 No 04/2018 The bed rocks, on which study area, rests are mainly dominance of sandy silt (Pithawalla and Martin-Kaye, composed of sandstone, siltstone with interbedded 1946; Shah, 2009). Due to the occurrence of variable shale and subordinate limestone followed by soft to rock resistance and rheology the topography of study hard sandstone which is highly conductive due to the area is highly undulatory. Fig. 1. Map showing sample locations plotted on the Google Earth Image. Fig. 2. Geological map of Gulistan-e-Johar town, Karachi. Khan, A & Khan, M.A./ JGEET Vol 03 No 04/2018 201 3. Materials and Methods Table 1 WQI range, status and possible usage of the water sample 3.1 Sample Collection Water samples (n=18) were collected through boring WQI Status Possible usages Drinking, irrigation wells at a depth range of 10 to 75 metres from various 0-25 Excellent and industrial localities of Gulistan-e-Johar town. Water was Domestic, irrigation 25-50 Good electrically pumped for 2-3 minutes to get and industial Irrigation and representative samples. Location of the boreholes were 51-75 Fair industrial taken by using Global Positioning System (GPS) and 76-100 Poor Irrigation marked on the Google image (Fig. 1). Water samples Restricted use for 101-150 Very poor were taken in polyethene bottles of 1 litre capacity for irrigation Proper treatment physico-chemical analysis. Bottles were rinsed Above 150 Unfit for drinking required before use thoroughly with distilled water and subsequently with the sample water on sampling site. Samples were It is simple method aimed at interpreting the separately collected in bottles of 200 ml capacity to concentration of parameters present, to express them determine nitrate content. About 1 ml of boric acid into a single value. It provides an extensive solution was added in each water sample to stop any clarification to rate the quality and its suitability for further reaction. different purposes including; drinking, irrigation, industrial, restricted etc. WQI is calculated using 3.2 Groundwater Analysis following formula. All the samples were examined for physicochemical parameters in the laboratory of Department of Geology, iWn n (1) University of Karachi except fluoride test, which was Where ,Q is the quality rating of nth water quality analyzed in Pakistan Council of Research in Water n parameter, W is the unit weight of nth water quality Resources (PCRWR). The pH & TDS of collected samples n parameter. were determined by using pH meter (ADWA AD 111) The quality rating Qn is calculated using the equation : and TDS meter (ADWA AD 330) respectively. Sodium and Potassium concentrations were determined by Qn =100 x [(Vn Vi) / (Vs Vi)] (2) using flame photometer (Model No. JENWAY PFP7). Sulphate concentration was determined by gravimetric Where, Vn is the actual amount of nth parameter method, while chloride and bicarbonate ions were present, Vi is the ideal value of the parameter, Vi = 0, estimated by argenometric titration method. For the except for pH (Vi = 7), Vs is the standard permissible determination of calcium and total hardness, EDTA value for the nth water quality parameter. titration method (1992) was applied. Amount of Unit weight (Wn) is calculated using the formula magnesium was determined by taking the difference of Wn = k/Vn (3) hardness and calcium using standard formula. Where, k is the constant of proportionality and it is Concentration of nitrate was determined by cadmium calculated using the equation reduction method (HA CH-8171) on spectrophotometer while the iron and manganese s (4) were determined by using Atomic Absorption Spectroscopy. 4. Results and Discussion 3.3 Water Quality Index 4.1 Physicochemical characteristics One of the most operational techniques to collect Groundwater samples (n=18) were collected from information of the water quality for the policy makers various parts of Gulistan-e-Johar town through and the citizens is Water Quality Index (Yisa and Jimoh, electrically pumped wells installed at various depths 2010). It was first proposed by Horton in 1965 which was later generalized by Brown et al. in 1970. Water (range = 34-250 feet). The results of all physicochemical quality index (WQI) is a number that evaluates the parameters have been summarized in Table 2. Due to quality of water by gathering different parameters, large variation in the well depths shallow (depth < 100 lower values refers to good or excellent quality while feet) and deep (depth > 100 feet) aquifers have been higher values refers to the bad or poor quality (Bharti, addressed separately. 2011). Weighted arithmetic index method of WQI proposed by Brown et al (1970) was applied to evaluate 4.2 Shallow Aquifers the groundwater quality of Gulistan-e-Johar Town. One third of total collected samples have been Physicochemical parameters including pH, TDS, major tapped from shallow aquifers ranging in depth between cations (Ca, Mg, Na and K) and anions (SO4, Cl, HCO3, 34-75 feet (Table 2). The pH of these samples is found NO3, Fe, Mn and F) were used to calculate WQI of to be slightly acidic (mean: 6.8). low pH of these water groundwater in study area. samples seems to be controlled by the geology of study area as rocks hosting these water bodies are mainly 202 Khan, A & Khan, M.A./ JGEET Vol 03 No 04/2018 comprised of sandstone.