Environmental Monitoring and Assessment (2006) 123: 299–312 DOI: 10.1007/s10661-006-9198-5 c Springer 2006 RISK ASSESSMENT OF PHYSICO-CHEMICAL CONTAMINANTS IN GROUNDWATER OF PETTAVAITHALAI AREA, TIRUCHIRAPPALLI, TAMILNADU – INDIA A. ABDUL JAMEEL1 and J. SIRAJUDEEN2,∗ 1Post – Graduate Studies and Research Department of Chemistry, Jamal Mohamed College, Tiruchirappalli – 620 020, Tamilnadu, India; 2Department of Chemistry, School of Engineering and Technology, Bharathidasan University, Tiruchirappalli – 620 024, Tamilnadu, India (∗author for correspondence, e-mail: siraju [email protected]) (Received 16 October 2005; accepted 16 January 2006) Abstract. A study was carried out in Pettavaithalai area to evaluate the current status of physico- chemical contaminants and their sources in groundwater. Groundwater samples collected from pet- tavaithalai area in 15 different stations were analyzed every alternative months over a period of two years from August 2000 to June 2002. A sugar mill is situated at the heart of the study area. Three profiles (profile A, B and C) were selected based on the direction in which the sugar mill effluent flows. In each profile five samples were collected from five different station at a regular distance of about 1 Km. The physico-chemical parameters such as pH, EC TDS, TH, NO3,SO4, PO4, Na, K, Ca, Mg, DO, BOD and COD have been analyzed. The results showed that among the three profiles, many of the estimated physico-chemical parameters of profile C were very high when compared to profile B and A which indicates the poor quality of the groundwater around this area. Keywords: physico-chemical contaminants, groundwater, Pettavaithalai, Tamil Nadu, India 1. Introduction Water is one of the most indispensable resources and is the elixir of life. Water constitutes about 70% of the body weight of almost all living organism. Life is not possible on this planet without water. It exists in three states namely solid, liquid and gas. It acts as a media for both chemical and biochemical reactions and also as internal and external medium for several organisms. About 97.2% of water on earth is salty and only 2.8% is present as fresh water from which about 20% constitutes ground water. Ground water is highly valued because of certain properties not possessed by surface water (Goel, 2000). The rapid growth of urban areas has further affected the ground water quality due to over exploitation of resources and improper waste disposal practices. The ground water quality of Pettaivaithalai area which is located about 25 Km from Tiruchirappalli district has been altered due to many anthropogenic activities. A sugar mill is located at the heart of this area. The effluent from this industry 300 A. ABDUL JAMEEL AND J. SIRAJUDEEN which is let into the ground, percolates and may change the ground water quality. Therefore it is essential for protection and management of the ground water quality. 2. Details of Study Area The details of the study area were collected from Public Works Department, Ground Water Division, Tamil Nadu Water and Drainage Board and Statistical Department, Tiruchirappalli. The details regarding the area are given below. 2.1. LOCATION Tiruchirappalli District is situated on the banks of the River Cauvery about 320 km southwest (SW) of Chennai. This city was the capital of Chola dynasty during the Sangam age. The Pandyas and Pallavas ruled over this region for short periods. The historic Rockfort had played a vital role in the carnatic wars in the 18th cen- tury. Today, Tiruchirappalli is a blend of history and tradition, a pilgrim centre as well as a thriving commercial city. It is one of the best educational cities in In- dia housing colleges with more than one hundred and fifty years of age. Bharath Heavy Electricals Limited (BHEL), locomotive service station of Southern Rail- ways, Ordnance Factory are some of the major industries of Tiruchirappalli. The Pettavaithalai area is situated about 25 km west of Tiruchirappalli. It is located be- tween the latitude of 10◦5300 and the longitude 78◦2900. The total area coverage is 367.735 hectares. A sugar mill with large scale production is located in the heart of the area. There are a large number of cottage industries and automobile service stations. 2.2. CLIMATE The area has a high mean temperature (28 ◦C) and low relative humidity. This gets more rainfall from northeast (NE) monsoon. Even though the region is quite hot, the difference between maximum and minimum temperatures is only moderate. The atmosphere is dry with little moisture during the beginning months of the year. When the season is cool, the climate is pleasant and enjoyable. The SW monsoon period lasts till August. Rainfall occurs from October to December. The maximum and minimum temperature are dominant by April to June and November to January respectively. 2.3. RAINFALL This area gets rainfall mostly from the NE monsoon. The average rainfall is about 818.52 mm. It gets more rainfall during the period of October and November. At the RISK ASSESSMENT OF PHYSICO-CHEMICAL CONTAMINANTS IN GROUNDWATER 301 same time there is no rainfall from February to April. The average rainfall around Pettavaithalai for the last three years (1999–2002) is about 880.16 mm. 2.4. SOIL The nature of soil in the study area is alluvium followed by Granitic gneisses. Alluvium soil constitutes major portion of the deltaic regions, bordering the river Cauvery. 2.5. AGRICULTURE The economy of the area is mainly based on agriculture. Farm output provides not only the food requirements of the area but a sizable portion of it is exported to other parts of Tamil Nadu. Alluvial type of soil around this area is well supplied with potash and magnesium, which is conducive for raising of crops. 2.6. VEGETATION Nearly 75% of the total area is under cultivation. Out of the total cropped area, 65% include food crops. The major crops cultivated are paddy, banana, sugar- cane and vegetables. Groundnut and pulses are predominantly cultivated as rainfed crops. 3. Materials and Methods During the study, sampling was carried out at the three different profiles (A, B and C) in 15 wells. The physico-chemical analysis was performed every alternative month over a period of two years from August 2000 to June 2002. Three profiles were selected based on the direction in which the sugar mill effluent flows. In each profile, five samples were collected from five different stations at a regular distance of about 1 Km. The locations of the study area and sampling stations are shown in Figure 1. The 5 stations of profile A are 1. Kottayathottam 2. Thiruchappur 3. Poyya- mani 4. Koraippatti 5. Nangavaram, profile B are 1. Sirukadu 2. Mangammasalai 3. Mill gate 4.Thirumurugannagar 5.Kaverinagar and profile C are 1. Sangiliyandapu- ram 2. Pettavaithalai mainroad 3. Kavakarapalayam 4. S.Pudukottai 5. Sirugamani. Samples were collected in pre cleaned 2 L polythene bottles with necessary pre- cautions (Brown et al., 1974). All the samples were examined to determine pH, EC TDS, TH, NO3,SO4,PO4, Na, K, Ca, Mg, DO, BOD and COD using standard methods of (APHA, 1995). 302 A. ABDUL JAMEEL AND J. SIRAJUDEEN Figure 1. Location map of pettavaithalai showing sampling station. 4. Results and Discussions The result regarding the mean values of the various physico-chemical parameters of ground water collected every alternative month from August 2000 to June 2002 are given in the Table I. 4.1. pH pH is the measure of acidity or alkalinity of water. In general, the mean pH values of all the three profiles lie more or less within the permissible limits of WHO (7.0–8.5) Table I. Slight changes are seen in the values of all the three profiles. This may be attributed to different types of buffers normally present in the ground water. The same is observed by Weber and Stun (1963, p.1553). The variations in pH are relatively small. However, the values reveal the slight alkaline nature of the ground water. This observation is in good agreement with RISK ASSESSMENT OF PHYSICO TABLE I Mean Physico-chemical parameters of ground water collected every alternative months from August 2000 to June 2002 Profile Station pH EC TDS TH CO3 HCO3 Cl F NO3 SO4 PO4 Na K Ca Mg DO BOD COD A 1 8.0 1017 682 320 14 433 112 1.2 7.5 67 0.14 127 13 67 43 4.7 4.5 15 2 7.8 858 568 319 4.0 421 91 0.9 8.6 47 0.20 94 19 68 30 5.4 3.2 14 3 7.8 885 635 243 4.0 333 74 1.1 8.0 58 0.31 123 11 68 46 4.9 3.1 16 4 8.2 811 516 269 23 238 101 1.1 5.6 69 0.33 126 13 68 52 4.4 4.7 15 5 7.8 797 1005 261 ND 612 178 0.8 27 160 0.39 297 7.0 66 52 4.5 3.3 12 - CHEMICAL CONTAMINANTS IN GROUNDWATER B 1 7.8 2555 1705 454 15 986 298 1.8 79 215 0.38 505 13.0 43 61 4.0 3.5 14 2 8.0 2979 1857 369 23 821 419 1.3 74 212 0.27 460 82 62 130 4.7 3.2 14 3 7.7 2433 1802 551 4.0 498 436 2.0 23 151 0.15 279 33 98 126 4.2 3.7 12 4 7.8 740 635 798 9.0 552 82 1.4 7.6 47 0.17 73 4.0 100 79 2.8 4.8 19 5 8.1 1529 945 939 7.0 459 138 0.9 5.9 128 0.47 233 5.0 66 54 4.2 3.3 14 C 1 8.3 558 362 252 37 338 70 1.8 5.4 36 0.32 76 8.0 63 51 3.9 6.5 24 2 7.9 5151 3501 905 3 924 1098 2.1 300 572 0.19 858 44 70 227 4.9 5.4 17 3 7.8 3971 3096 1171 ND 1315 711 1.5 166 311 0.23 501 38 88 115 4.3 4.9 18 4 8.3 3106 1345 760 37 488 395 1.1 91 184 0.18 276 17 140 186 3.5 5.6 19 5 7.9 6078 3037 1285 5.0 533 1176 1.0 12.2 548 0.26 464 9.0 185 253 3.9 3.3 12 WHO values 7–8.5 600 500 500 50 500 250 1.5 50 250 0.10 200 12 100 150 6.0 5.0 10 All the values are expressed in ppm except pH and EC.