Geochemical Evaluation of Groundwater Quality in Selected Areas of Hyderabad, A.P., India G
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546 Indian Journal of Science and Technology Vol. 3 No. 5 (May 2010) ISSN: 0974- 6846 Geochemical evaluation of groundwater quality in selected areas of Hyderabad, A.P., India G. Udayalaxmi, D. Himabindu and G. Ramadass Centre of Exploration Geophysics, Osmania University, Hyderabad–500 007, India [email protected] Abstract This paper examines the quality of groundwater in a 40 sq km region comprising Osmania University and surrounding areas in the north eastern part of Hyderabad city in India. 171 groundwater samples from bore wells in the region have + + 2+ 2+ - - 2- - 2- been analyzed for ionic concentrations of K , Na , Ca , Mg , F , Cl , SO4 , HCO3 and NO3 . Parameters such as pH, total hardness (TH), total dissolved solids (TDS), sodium absorption ratio (SAR), permeability index (PI), residual carbonate (RC), electrical conductance (EC) and groundwater quality index (GWQI) have been evaluated, contoured and analyzed to determine the areas of contaminated groundwater. It is inferred from Wilcox plot and Piper trilinear diagram, the samples in the study area falls under C3S1 class and characterized by alkaline. It was found the groundwater in the entire region is too hard for drinking. Groundwater contamination in the study area is attributable to different sources; in the southern part of the study area, it is due to proximity to the river Musi that acts as a carrier of domestic and industrial effluents. In and around Nacharam and Mallapur, the effluents discharged from the several industries are responsible for polluting the groundwater in the region. Regions such as Jamai Osmania, Lallaguda and Lalapet are very densely populated and it is the domestic sewage in this area that is the primary cause of groundwater contamination. Keywords: Geochemical analysis, groundwater quality index (GWQI), Hyderabad. Introduction terms of population, area and land use, and with its As the distribution of surface sources of water is so heterogeneous demographic profile, is cosmopolitan in its uneven as to be inadequate, in many parts of the country truest sense. The study area has an approximate extent the dependence on groundwater is almost total. This is of 40 sq kms and lies in Ranga Reddy district between especially true in regions of arid to semi-arid type of latitudes 17.3750 (17o22’30”N) and 17.50 (17o30’N) and climate where average annual rainfall is less than 100 cm longitudes 78.50 (78o30’E) to 78.60 (78o 37’E) in degrees and the scope of aquifer recharge is limited. Thus, (Survey of India toposheet number 56K/11/NW). Fig.1 is groundwater continues to be exploited at ever increasing a location map of the study area. Physiographically, the rates, especially in the rapidly expanding urban areas of area represents flat topography with gentle slope. The the country. But rapid urban sprawl and industrialization drainage pattern; it varies from dentritic to sub- have the unfortunate fallout of environmental pollution. In parallel/rectangular trellis. the absence of appropriate waste management Geochemical analyses strategies, many human activities and their by-products In the present study 171 ground water samples were have the potential to pollute surface and subsurface collected from bore wells located in parts of the city in water. Industrial effluents, and wastes from urban Dec 2007. The geographic coordinates of the locations of infrastructure, agriculture, horticulture, transport and these samples were determined using a GPS and are discharges from abandoned mines and deliberate or shown in Fig.1. These samples were analyzed for + + 2+ - - 2- accidental pollution, all eventually affect the water quality. constituents like pH, TDS, K , Na , Mg , F , Cl , SO4 , 2- 2+ - The pollutants from the stream may move slowly in to the NO3 , Ca , TH, HCO3 and E.C by standard methods in ground, thus affecting the quality of groundwater. the geochemical laboratory of the National Geophysical Depending on various natural and cultural factors, the Research Institute (NGRI), as per the standard procedure quality of groundwater in terms of its physical, chemical for American Public Health Association (Browen et al., and organic characteristics is variable, determining its 1974; APHA, 1985; 1998). Apart from the above, the suitability for different purposes– domestic, agricultural or sodium absorption ratio (SAR), permeability index (PI), industrial. This paper studies the extent and degree of residual carbonate (RC), alkalinity and the groundwater groundwater contamination in a part of the city of quality index (GWQI), were also determined. Table 1 Hyderabad from geochemical analysis of groundwater summarized the evaluated statistical parameters namely samples. minimum (min), maximum (max), mean and standard Study area deviation (S.D) values for each of the measured Hyderabad, the capital of Andhra Pradesh, is located constituents of the groundwater samples from study area. between latitude 17o 15’N to 17o35’N and longitude pH: The pH an aqueous solution is measure of the 78o20’E to 78o37’E. It is the sixth largest city of India number of hydrogen ions or protons present and (2001). It is one of the fastest growing metropolises in measured with a pH meter (Hem, 1985). It is expressed Research article “Groundwater quality in Hyderabad” Udayalaxmi et al. ©Indian Society for Education and Environment (iSee) http://www.indjst.org Indian J.Sci.Technol. 547 Indian Journal of Science and Technology Vol. 3 No. 5 (May 2010) ISSN: 0974- 6846 as the negative logarithm the Table 1. Statistics of groundwater quality analysis in µS/cm) are observed over hydrogen-ion concentration in OU and surrounding areas of Hyderabad, Dec 2007 Jamai Osmania, north of water. The pH of the analyzed (all values in mg/l except pH & E.C). Nacharam and around samples in the study area (Fig. Parameter Min Max Mean S D Mallapur. Such anomalous 2a) varies from 6.2 to 8.65 pH 6.2 8.65 7.54 0.440 values arise from various against permissible limits of 6.5 EC (µS/cm) 222.9 5086.9 1898.4 868.02 anthropogenic activities and to 8.5 (BIS, 1983). The TDS (mg/l) 29.9 2330 1044.53 421.55 geochemical processes Na+ (mg/l) 2.5 455 122.8 80.3 measure of pH is on a scale of + prevailing in the region (Sujatha 0-14 wherein pH less than 7 is K (mg/l) 0.2 28.4 6.8 4.39 & Reddy, 2004). Mg++ (mg/l) 10 525 93.5 98.8 acidic and greater than 7 is ++ Total dissolved solids (TDS): alkaline (basic) and exact 7 is Ca (mg/l) 16 860 192.9 149.78 The weight of the residue Cl- (mg/l) 30 1020.0 287.8 192.5 neutral. Thus the groundwater -- consisting of pollutants SO4 (mg/l) 14 361.2 111.6 68.97 samples are, at places slightly - (dissolved ions) left behind after HCO3 (mg/l) 30 622.2 275.5 144.6 more basic than acceptable - all the water from a water NO3 (mg/l) 0.1 326.0 77.5 69.86 limits. Values of over 8 are F-(mg/l) 0.0 7.0 1.7 1.11 sample is evaporated is a noticed near Uppal, Tarnaka, TH 117.9 3712.3 862.5 723.7 measure of the TDS and gives Pedda cheruvu and Nadimi SAR 0.0 8.5 2.2 1.55 the general nature of cheruvu. Similarly, values less RC (me/l) -71.0 1.8 -12.6 14.3 groundwater quality and extent than 7 occur near Jamai of contamination (Annon, 1946; Osmania, northeast of Safilguda and around Mallapur. Robinnove, 1958; Davis & de Wiest, 1966; AWWA, E.C: Electrical Conductivity (EC) depends upon 1971). The permissible limit (BIS, 1983) for TDS is about temperature, ionic concentration and types of ions 500 mg/l. In general, TDS values of <1000 mg/l are present in the water (Hem, 1985). Thus the EC gives a considered as fresh water and values >1000 mg/l are qualitative picture of the quality of groundwater. The considered brackish. The TDS values vary between 29.9 maximum permissible limit of EC in groundwater (BIS, to 2330 mg/l with mean value of 1044 mg/l. The 1983) is 1500 µS/cm. It varies from about 222 to 5086 measured TDS values in the study area contoured with µS/cm with the mean value of 1898 µS/cm in the study an interval of 100 mg/l are shown in Fig. 2c. Except for area (Fig. 2b). Except for the region between Pedda the region to the northwest of Moulali where TDS values cheruvu and Uppal, and small regions off Moulali and of <500 are observed, in the industrial zones (Nacharam Mallapur, the entire study area has values of EC that & Mallapur) and several residential zones high exceed permissible limits. Anomalous peaks (>3000 concentrations ranging between 1500-2300 mg/l are Fig. 1. Location map of groundwater samples for observed. The higher concentrations were due to geochemical analysis in OU & Surrounding areas, Hyderabad leaching of solid wastes from ground surface as well as enhanced seepage from lakes during monsoon. In Kapra cheruvu 0 2 km general, the TDS concentration were found to 68 66 17.48 67 125 6465 134 increase downstream, possibly due to topography 126 Sample location 69 71 70 7475 gradient, deposition of silt due to erosion and floods RK Puram Lake 72 77 along drainage channels and tanks, as also due to 170128 78 127 88 Safilguda 80 industrial and municipal waste disposal (Freeze & Nadimi81 cheruvu8579 129 17.46 82 91 Moula Ali 95 130 Miryalguda159 87 cheruvu89 84 86 Cherry, 1979). 132 - 83 53 Chloride (Cl ): Chloride concentration of the 92 93 90 54 2850151 42 27 groundwater samples in the study area is varying 225246 4148 29 21Mallapur47353949 44454336513740 3823 26 from 30 to 1020 mg/l, with average value of 287mg/l.