Science, Volume 1, Number 1, November 2012 RESEARCH
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RESEARCH Indian Journal of Science, Volume 1, Number 1, November 2012 RESEARCH 49 77 – Indian Journal of EISSN 2319 30 77 – S cience ISSN 2319 Groundwater Quality Assessment in Part of Chennai City, Tamil Nadu, India – Case Study Annapoorani A1, Murugesan A2,*, Ramu A3, Renganathan NG4 1. Department of Chemistry, Vel Tech Multi Tech Dr RR, Dr SR Engineering College, Avadi, Chennai-600 062 (Tamil Nadu) India 2. Department of Chemistry, Sriram Engineering College, Perumalpattu, Veppampattu RS, Chennai-602 024 (Tamil Nadu) India. 3. School of Chemistry, Madurai Kamaraj University, Madurai – 625 021(Tamil Nadu) India. 4. Department of Chemistry, Vel Tech Dr RR, Dr SR Technical University, Avadi, Chennai – 600 062 (Tamil Nadu) India *Correspondence to: Department of Chemistry, Sriram Engineering College, Perumalpattu, Veppampattu RS, Chennai-602 024 (Tamil Nadu) India. Received 27 September; accepted 15 October; published online 01 November; printed 16 November 2012 ABSTRACT An assessment of contaminants in groundwater quality in Chennai City, Tamil Nadu, and India has been made in this paper. The pH, EC, TDS, Ca2+, 2+ + + - - 2- 2- - - Mg , Na , K , Cl , HCO3 , CO3 , SO4 , OH , F , hardness, DO, and BOD were analysed and compared with the WHO (World Health Organisation) and ICMR(Indian Council of Medical Research) standards. Relationship between ions can be derived from the application of statistical analysis of the data. Correlation analysis is used to identify geochemical processes controlling groundwater geochemistry. The chemical analysis indicates that in all water samples analysed, sodium ion was found to be the dominant cation species, except in the case of G31. WQI (Water Quality Index) was less than 20% in the study area indicating that quality of water was reduced due to intrusion of sea water or anthropogenic agents. Keywords: Ground Water Quality, Chennai City, WQI 1. INTRODUCTION Groundwater usage increases day by day for the domestic & industrial sectors. Several factors such as climate, characteristics of soil, circulation of groundwater through the rock types, topography of the area, intrusion of saline water in coastal areas, human activities on the ground, etc posses severe effects on the quality of water. Now a day, ground water level has gone down and tap water bore wells has to be made atleast 200-500m deep for good quality water (Giridharan et al 2009, Raj Mohan et al 2006, Senthil Kumar et al 2008, Elango et al 1992, Rengaraj et al 1996). This is due to the fact large quantity of water needed in all the sectors and as a result of this, water level decreases. This forces the diffusion and percolation of water from coasts as an act of recharging and thereby, the fresh water becomes saline due to sea water intrusion (Adepelumi et al 2009, Terzic et al 2008, Nasab et al 2010, Mondal et al 2010, Elango 2009J). To identify the contamination of ground water, various water samples were collected from different parts of Chennai city and were analyzed. For this purpose, spatial distribution has been performed using GIS and the study areas have been chosen and analyzed to get various parameters like The pH, EC,TDS, Ca2+, 2+ + + - - 2- 2- - - Mg , Na , K , Cl , HCO3 , CO3 , SO4 , OH , F , hardness, DO, and BOD. The values obtained were compared with standard values (WHO and ICMR). 2. STUDY AREAS CHOSEN Chennai is situated in south eastern coast of Indian peninsular and it is the fourth largest metropolitan cities of India. It is bordered by Bay of Bengal in the east, while the state of Andhra Pradesh is on its northwest, Kanchipuram districts on its south and Thiruvallur on its western side. The latitude and longitude of the study area is 12.99093 to 13.11994 and 80.0488 to 80.19874 (Fig 1). Major water supply to the Chennai city is ground water Figure 1 which is recharged by north east monsoon but virtually gets Study area map of part of Chennai city, Tamilnadu, India exhausted before the next annual rainfall in Chennai city. 47 Coovum river flows through the center and the Adyar river flows Annapoorani et al. Groundwater Quality Assessment in Part of Chennai City, Tamil Nadu, India – Case Study, Indian Journal of Science, 2012, 1(1), 47-50, www.discovery.org.in http://www.discovery.org.in/ijs.htm © 2012 discovery publication. All rights reserved RESEARCH towards south, apart from this Buckingham canal is running parallel to the coast and linking the two rivers. 3. METHODOLOGY The important parameters measured insitu are EC, pH, TDS. All the experiments were carried out using AR chemicals and double distilled water. Chloride, alkalinity and hardness were determined by the volumetric titration. Sodium and Potassium were determined using Flame Photometer. Sulphate, Nitrate, Phosphate, Fluoride were determined by using UV Visible Spectrophotometer. Calcium and Magnesium are determined by complexometric titrations involving EDTA. DO and BOD were analyzed by Iodometric titration. SPSS Software was used to identify the important ions present in the water samples. Map of the study area and spatial variation was done using GIS Software. Heavy Metals were analyzed using AAS. Table I Physico-Chemical Parameters of Ground Water Samples in Chennai City 4. RESULTS AND - - - - Code Na K TDS Cl TH HCO3 CR Cl /HCO3 Sulphate DISCUSSION G4 422.8 82.4 870 226.88 220 260 6.47 0.87 18.7 All the major elements were studied for 11 G6 480.5 376.2 920 228.65 300 540 6.48 0.42 20.3 samples out of 35 samples part of the Chennai G7 608.9 13.2 910 292.46 262.5 400 8.27 0.73 11.5 city, Tamil Nadu and the results are provided G11 435.5 16.8 1210 620.38 362.5 560 17.5 1.11 13.1 in Table I. The pH value for all the water G14 352.3 66.6 1060 324.37 457.5 360 9.17 0.9 12.6 samples vary from 5.5 to 7 indicating that G17 564.9 7.4 1320 496.3 425 520 14.03 0.95 26.6 water samples contain bicarbonate as well as G22 351.5 2.4 1120 496.3 550 440 14.03 1.13 19.4 carbonic acid but not carbonate anions. For G25 426.7 113.7 1170 264.1 385 580 7.47 0.46 19.1 G28 692.7 43.5 920 313.73 350 500 8.87 0.63 17.3 these samples Electrical conductivity varies G31 1146 4.5 1830 735.59 700 520 20.75 1.41 16.3 from 1269.8 to 2904.8. According to Sexana G38 693.3 17.5 800 216.25 252.5 440 6.12 0.49 11.3 et al 2003 groundwater in this area has been G40 691.1 52.4 1430 716.09 932.5 420 20.21 1.7 16.9 classified as 42% of the water is fresh water. The remaining 58% of the water has started to convert as brackish water. Again it is observed from the Table I that Total dissolved solids varied from 800-1830ppm shown in Fig 2B. Higher value of EC and TDS were recorded in the bore well of (G11, G14, G17, G22, G25, G31, G40). Based on TDS values, Carroll et al 1962, has reported that only 42% of the sample was found to be freshwater and the remaining area has started to become brackish water. Figure 2A Figure 2B Figure 2C Total hardness Total dissolved solids Nitrate Total Hardness depends upon the calcium and magnesium present in the water samples and it varied from 200 to 932 ppm. 50% samples were found to be hard in nature and it is shown in Fig 2A. Chemical analysis of water samples indicates that the most dominating cation to be sodium and anion to chloride, except sample G31 (1146 ppm). But for all the other samples sodium content was within the permissible limits. As usually, the potassium content of waters was found to be lesser than sodium, calcium, magnesium except in G6 (371 ppm). The concentration of carbonate ions were in traces, and the bicarbonates concentrations were found high in all water samples that were analysed. From Fig 4, it is clear that among the anions, chloride was the most dominating anion and varied from 216.25-735.59ppm. Another important major anion was sulphate which may be due to geological sources by Gupta et al 1975. Nitrate and phospahate concentrations present in the samples were ≤50ppm and ≤ 2ppm respectively, indicating that agricultural land has been converted into residential land (Fig 2C). It can be envisaged from Fig 10 that the concentration of Zn2+, Fe3+, Cu2+ were found to be ≤ 0.5 ppm, ≤ 5 ppm and ≤ - - 0.2ppm respectively, in all the samples. The Cl /HCO3 ratio was <2 for all the samples, indicating there was no intrusion of sea water as shown in Fig 3. In addition, Mg2+/Ca2+ ratio was found to be >1, which confirms that there is no intrusion of sea water taken place. Corrosivity Ratio was > 1 indicates the presence of Figure 3 3+ mineral Fe ions naturally in all the water samples, and was not Plot between Ionic Ratio and Samples 48 due to the salt content in water (Rengarajan et al 1990). Water Annapoorani et al. Groundwater Quality Assessment in Part of Chennai City, Tamil Nadu, India – Case Study, Indian Journal of Science, 2012, 1(1), 47-50, www.discovery.org.in http://www.discovery.org.in/ijs.htm © 2012 discovery publication. All rights reserved RESEARCH Table II Correlation between ions present in groundwater in Chennai city Quality Index is less than 20% in all the water samples.