I Research Journal of Environment Sciences__________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 19 Hydrochemical Characteristics of Groundwater for Domestic and Irrigation Purposes in Periyakulam Taluk of Theni District, Tamil Nadu Ramesh K. and Bhuvana Jagadeeswari. P Centre for Water Resources, Dept of Civil Engineering, Anna University, Chennai, TN, INDIA. Available online at: www.isca.in Received 3rd July 2012, revised 26th July 2012, accepted 30th July 2012Abstract Study was carried out in Periyakulam taluk of Theni district in Tamil Nadu, India with an objective of understanding the suitability of local groundwater quality for domestic and irrigation purposes. Thirty groundwater samples were collected in premonsoon (August 2011) and postmonsoon (February 2012) and analysed for physical and chemical parameters. Groundwater in this area was found to be within desirable Bureau of Indian Standards for drinking water except certain location hardness and Fluoride exceeds the permissible limit (more than 1.5 mg/l). The presence of fluoride above the permissible level have created a serious threat to rural population dental fluorosis have appeared alarming rate in certain regions. Hydrochemical groundwater evaluations revealed that most of the groundwater belongs to the Ca-HCO type and mixed Ca-Mg-Cl type. Base-exchange indices classified 83% of the groundwater sources as the Na-SO2- and 73% belong to Na-HCO type pre and postmonsoon. The meteoric genesis indices demonstrated that 73% of groundwater sources belong to a deep meteoric water percolation type before monsoon and 76% belong to a shallow meteoric water type in after monsoon season. Groundwater in this area was assessed for irrigation purposes on the basis of salinity indices, chloronity indices, sodicity indices, sodium percentage, and residual sodium carbonate classification. Most of the groundwater samples were suitable for irrigation except in a few locations. Keywords: Physicochemical characteristics, domestic and irrigation suitability periyakulam taluk. Introduction The quality of water is vital concern for mankind since it is directly linked with human health. Groundwater is highly valued because it constitutes the major drinking and irrigation water source in most of the parts of India. In recent decades, exploitation of groundwater has increased greatly, particularly for agricultural purpose, because large parts of the country have little access to rainfall due to frequent failures of monsoon. Presently, 85% of the water requirement for domestic use in rural areas, 55% for irrigation and over 50% for industrial and urban uses is met from groundwater.Groundwater irrigation started with only 6.5 Mha in 1950-51, which was increased to 46.5 Mha in 2000-200117 meeting about 70% of the irrigation water requirements of the country. This clearly indicates the growing pressure on groundwater resources. There is growing concern on the deterioration of groundwater quality due to geogenic and anthropogenic activities . The quality of groundwater in a region is a function of physical, chemical and biological parameters. Groundwater quality is as important as the quantity. Poor quality of water adversely affects the plant growth and human health 9,19,20,21. It decreases agricultural production; reduce agrarian economy, retards improvement in the living conditions of rural people. Potable water is the water that is free from disease producing chemical substances and microorganisms that are dangerous to health, majority of the rural people do not have accesses to potable water for domestic use. Several regions in India have encountered degradation in groundwater quality too, due to increase of population growth and rapid urbanization 3,14. The present study carried out with the aim of understanding the groundwater quality and its suitability for domestic and irrigation purpose. Groundwater is usually as direct use in rural water supply without proper treatment and for agricultural practice most of the year. Groundwater may also contaminated due weathering of rock and agrochemicals used for irrigation in this area. However, no studies have been carried out in the with respect to drinking and irrigation purpose so far in the rural area of Periyakulam taluk. The present study, which was carried out in premonsoon (August 2011) and Postmonsoon (Febrary 2012), from the area are selected for the present study. Study Area: The study has been carried out in Periyakulam Taluk is situated in Theni district southwest of Tamil Nadu. It is located 482 Km south of Chennai city and covers an area of 390.03 km. The taluk is situated between the latitudes 9°53’N to 10°14’N and longitudes 77°17’E and 78°45’E. It is bound by Bodinayakkanur and Theni taluk on the western side, south by Andipatti taluk and in the north and eastern side by Dindigul and Madural districts. Vaigai dam is located in this taluk and flowing during monsoon season and it normally is dry during summer season. The average temperature of the taluk is about 13ΊC to 40ΊC and average annual rainfall is about 868 mm. Agriculture is principle occupation of the people and is backbone of the rural economy. The crops cultivated are paddy, millets, cereals, I Research Journal of Environment Sciences________________________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 20 sugarcane, groundnut etc. Geologically this area is characterized by granitie gnesiss, charnockite and pegmatite of hard crystalline rocks. Deep red soil, laterite soil and red sandy soil overlay the rock formation. Farmers are using huge amount of chemical fertilizers and pesticides. The villages are well connected by roads to the nearest towns are Periyakkulam. The map of the study is shown in fig 1.Material and MethodsGroundwater samples were collected after well inventory survey from 30 representative wells during August 2011 and February 2012. The parameters like EC, pH were measured on the spot at the time of sample collection using potable kit. The collected groundwater samples were transferred into plastic container for analysis of chemical characters. Chemical analyses were carried out for the major ions, and trace ions concentrations using the standard procedures recommended by American Public Health Association. Generally groundwater is used as for drinking and irrigation purpose in this taluk. Results and Discussion The physical observations of the samples are colourless and odorless in natures which are given in the table 1. From these data, the following observations were made for different parameters: pH and Electrical conductivity (EC): pH is a measure of the intensity of acidity or alkalinity conditions of a solution. Most of the water samples are slightly alkaline due to presence of carbonates and bicarbonates 11. The pH values of water samples varied between 6.9 to 7.9 in pre and 6.8 to 7.9 in post monsoon and were found within the limit (6.5 - 8.5) prescribed by BIS. EC is the most important parameter to demarcate salinity hazard and suitability of water for irrigation purpose. It signifies the amount of total dissolved solid. EC values were in the range of 100 to 2620 S/cm and 80 to 5300 S/cm during pre and postmonsoon, respectively. The high conductivity in some of the samples is likely due to prolonged and intensive agricultural practices and geological conditions acquiring high concentrations of the dissolved minerals. Calcium (Ca2+) and Magnesium (Mg2+): Calcium content is very common in groundwater, because they are available in most of the rocks, abundantly and directly related to hardness. Calcium concentration varies between 10 to 140 mg/l and 40 to 150 mg/l during both the seasons and found exceed permissible limit (75 mg/l) in many locations as per BIS. Magnesium (Mg2+) usually occurs in lesser concentration than calcium due to the fact that the dissolution of magnesium rich minerals is slow process. Magnesium concentration varies between 6 to 84 mg/l and 14 to 100 mg/l during both the seasons which were found most of samples exceed the prescribed limit (30 mg/l) as per BIS. If the concentration of calcium and magnesium in drinking water is more than the permissible limit, it causes unpleasant taste to the water. Sodium (Na) and Potassium (K): Sodium concentration more than 50 mg/l makes the water salt taste and cause health problems. Sodium concentrations were found in between 45 to 114 mg/l and 49 to 141 mg/l during both the seasons. In general sodium salts are not actually toxic substances to humans because of the efficiency with which mature kidneys excrete sodium. Sodium concentrations values were found within the permissible limit (250 mg/l) as per BIS. Potassium is slightly less common than sodium in igneous rocks, but more abundant in all the sedimentary rocks. The main source of potassium in groundwater is weathering of potash silicate minerals, potash fertilizers and also due to surface water for irrigation. Potassium varies from 0.5 to 19.20 mg/l and 0.18 and 26.3 mg/l during both the seasons. Bicarbonate (HCO) and Carbonate (CO): The primary source of CO and HCO ions in groundwater is the dissolved CO in rainwater that on entering in the soil dissolves more CO. Bicarbonate concentration varied from 136 to 480 mg/l in pre monsoon and 125 to 460 mg/l in post monsoon. HCOconcentration few groundwater samples exceed the permissible (.71;ᜰ250 mg/l) limit as per BIS. Carbonate concentration varied from 0 to 20 mg/l in pre monsoon and 0 to 35 mg/l in post monsoon. Both CO and HCOcontribute to the alkalinity of the water and are associated with the hardness of water which gives an unpleasant taste to water. Normally in natural water as the pH value ranges from 7.0-8.0 would contain much more bicarbonates than carbonates (Chow 1964).Alkalinity of the circulating water is mainly responsible for the increase concentration of fluoride.Chloride and Sulphate (SO2-): The chloride concentration due to domestic sewage, fertilizers applications and/or leaching from upper soil layers in semi arid climates. Small amounts of chlorides are required for normal cell functions in plant and animal life. Chloride concentration varies between 7.5 to 542 mg/l and 9 to 1490 mg/l during both the seasons and found few samples exceed the prescribed limit (250 mg/l) as per BIS. Sulphate occurs naturally in water due to leaching from gypsum, other common minerals and discharge of domestic sewage tends to increase its concentration. Sulphate concentration varied between 8 to 200 mg/l and 10 and 180 mg/l during both the seasons and found within the prescribed limit (400 mg/l) as per BIS. Sulphate are related to the types of minerals in the soil and bedrock. Sulfur in the form of sulphate is an essential plant nutrient and is considered toxic to plants or animals at lower concentration, but at higher concentrations, it imparts a bitter taste and may cause laxative effects. Nitrate and Fluoride: Groundwater contain nitrate due to leaching of nitrate with the percolating water. Nitrate concentration in the sample ranges from 1 to 12 mg/l and 4 to 21 mg/l during both the seasons and found within the permissible limit (45 mg/l) as per BIS. The permissible limit of fluoride in drinking water is 1.0 mg/l, which can extend to 1.5 mg/l in case of non availability of other sources. Higher fluoride level in drinking water gives rise to dental decay and physical deformation. The fluoride content in the study area varied in the range 0.2 to 2.8 mg/l and 0.2 to 2.6 mg/l during both the season as shown in fig 2. It has been observed that groundwater in A.Vadipatti Gullapuram I Research Journal of Environment Sciences________________________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 21 Bomminayanpatti Marugalpatti locations contained higher fluoride concentration than prescribed limit and the habitant in this area affected by dental fluorosis diseases, The concentration of fluoride in groundwater is not uniform in the area. This may be due to the difference in the presence and accessibility of fluorine-bearing minerals to the circulating water and also due to the weathering and leaching activities. Total Hardness: Total hardness is an important parameter of water for its use in domestic purpose. Calcium and magnesium are important parameter for total hardness in groundwater. The acceptable limits for domestic use 75 mg/l. Total hardness of groundwater ranged from 50 to 700 mg/l and 53 to 800 mg/l during both the seasons. Excess hardness is undesirable mostly for economic or aesthetic reasons 13. Most of the samples are hard to very hard water. Hydrochemical Facies: Major cations and anions such as Ca2+, Mg2+, Na, K, CO, HCO, SO2- and Cl in mg/l were plotted in Piper diagram 12 to evaluate the hydrogeochemistry of groundwater of Periyakulam taluk with th help of Aquachem Software (Fig 3). The plot shows that most of groundwater samples fall in the field of mixed CaHCO type and mixed CaMgCl type facies type of water in both the seasons.Classification of groundwater samples: Groundwater samples were classified based on Cl, SO2 , and HCO concentrations 1, 18. Based on the Soltan’s classification, majority of the groundwater samples are of normal sulfate type followed by normal chloride and normal bicarbonate type.Base-exchange indices (r1): The base-exchange indices were estimated using equation18 to further classify groundwater. r1 = (Na - Cl) / SO2- Where r1 is the Base Exchange index and Na, Cl- and SO2-concentrations are expressed in meq/l. If r 1, the groundwater sources are of Na+ - SO2- type, while r1 .71;γˆ€ 1 indicates the sources are of Na - HCO type. Based on the Base Exchange indices (r) about 80% groundwater samples are classified as Na+ - SO2- type (r 1) and rest are Na - HCO type (r 1). Base-exchange indices classified 83% of the groundwater sources as the NaSO2- and 73% belong to Na-HCO type pre and postmonsoon which are given in the table 2. Meteoric genesis indices (r2): The groundwater sources can also be classified based on meteoric genesis index and can be computed using equation 18 r = ((Na + K) – Cl) / SO2- Where r is the Meteoric genesis index and the concentrations of , Na, Cl and SO2- are expressed in meq/l. If r2 1the groundwater source is of deep meteoric water percolation type while r2 .71;ᜰ 1 indicates that is of shallow meteoric genesis indices (r). Based on r2 values groundwater sources are of deep meteoric water percolation type and the rest are shallow meteoric water percolation type. Furthermore all Na+ - SO2- (except sample) type groundwater samples are of deep meteoric water and percolation type in nature. Similar findings were reported earlier16. The meteoric genesis indices demonstrated that 73% of groundwater sources belong to a deep meteoric water percolation type before monsoon and 76% belong to a shallow meteroric water type in after monsoon season which are given in the table 2. Mechanisms of controlling groundwater chemistry (Gibbs ratio): Gibbs diagram represents the ratio of Na+K+/Na+K+Ca and Cl/(Cl+HCO3) as a function of TDS which is widely used to assess the functional sources of dissolved chemical constituents such as, precipitation dominance, rock dominance and evaporation dominance. The chemical data of the groundwater samples from periyakulam taluk are plotted in Gibb’s diagram (Fig 4) which shows that most of the samples of the study area fall in the category of rock dominance and the evaporation, indicating that this process is also responsible for the groundwater chemistry. So the chemical weathering of the rock minerals could be the main processes which also contribute ions to the groundwater of the study area.Suitability for irrigational purposes: Groundwater in the study area is extensively used for irrigation. Good quality irrigation water is essential for achieving maximum crop productivity. Groundwater suitability for irrigation purpose in this study was assessed using salinity, chlorinity and sodicity indices (Mills 2003). Groundwater in most of the study area was found to be suitable for irrigation.Salinity index: Salinity index of the water samples was computed using the measured EC values. Salinity is related to TDS and EC. The total salt content of water gives the salinity. High concentrations of TDS and EC in irrigation water may increase the soil salinity, which affects the plant salt intake. Furthermore, salts types responsible for make up this salinity determine the water suitability for its intended use according to the following classification10, 16. The salinity index was estimated using the measured EC values. Majority of groundwater samples (97%) in the study area are categorized as class I–III, and thus, may be considered safe for irrigation. However, 3% water samples exhibit high to very high salinity (classes IV– V) and may not be suitable for irrigation (Fig. 5).Chlorinity index: The chloride ion can be toxic to plants having high salt tolerance when taken up by their roots and absorbed through their leaves. The chlorinity index of the groundwater sources was computed using measured chloride ion concentrations. Water samples in the study area were classified 10, 16 based on the following chlorinity index diagram. Based on the chlorinity index diagram, all the groundwater samples can be considered suitable (classes I and II) for irrigation (Fig. 6).Sodium Adsorption Ratio: Sodium Adsorption Ratio (SAR) is most commonly used to assess suitability of irrigation water. The SAR measures sodicity in terms of the relative concentration of sodium ions to the sum of calcium and magnesium ions in a water sample. Sodium concentration in water effects deterioration of the I Research Journal of Environment Sciences________________________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 22 soil properties reducing permeability 15. SAR is calculated using the following formula:SAR = Na+ (Ca2+ + Mg2+/2) Where the ionic concentrations are expressed in meq/l. The SAR is used to predict the sodium hazard of high carbonate waters especially if they contain no residual alkali 10. Based on the sodicity diagram the groundwater samples are classified and shown in fig 7. It is clear from fig 7 that all samples can be considered suitable for irrigation purposes. Percentage Sodium: Sodium is an important parameter for irrigation water and is denoted as Na% which was calculated from the formula given in equation 21 and all concentrations were expressed in meq/l.Na+ %= (Na + K) X 100 / (Ca2+ + Mg2+ + Na + KBased on the above Na% groundwater samples are classified as shown in Wilcox diagram (Fig 7). EC and Na% are plotted in Figure 8 which showed that most of the samples good to permissible and few samples fall under doubtful to unsuitable category, indicating the dominance of ion exchange and weathering from litho units of the study area. Residual sodium carbonate: The concentration of carbonate and bicarbonate higher than the alkaline earth mainly calcium and magnesium concentration, the water quality may be diminished and affects agriculture unfavorably 6,15. RSC can be computed using the following formula, where ions wee expressed in meq/l. RSC = (CO2- + HCO) – (Ca2++Mg2+) If RSC 1.25 meq/l, the water is considered safe. If RSC lies between 1.25 -2.5 meq/l, the water is of marginal quality. If RSC .71;β‘°2.5meq/l, the water is unsuitable for irrigation. Figure 7 clearly shows that all the samples were 1.25meq/l and fall within the safe category for irrigation purpose (Fig 9). Conclusion Groundwater quality of an area must be studied to understand its suitability for domestic and irrigation purposes. Generally, the groundwater quality of the area is hard to very hard, fresh to brackish and slightly alkaline in nature. The dominant groundwater type was Ca-HCO type and mixed Ca-Mg-Cl type. The major ions in most of the locations were found to be within in BIS permissible limit for drinking water. The groundwater is hard to very hard on the basis of TH. The fluoride concentration in the groundwater is also within BIS limit of 1.5mg.l. However some locations in A.Vadipatti, Gullapuram, Bomminayanpatti, Erumalainickenpatti and Marugalpatti the fluoride concentration exceed the limit (.71;γˆ€1.5 mg/l) and also observed the dental fluorosis is common among the people. People have to be advised to avoid the groundwater sources and advised to use surface water especially river water supply schemes as far as possible. The suitability of groundwater for irrigation was assessed from salinity indices, chloronity indices, sodicity indices, sodium percentage, and residual sodium carbonate classification. The groundwater in this area was seen to be good and suitable for irrigation purposes. References 1.APHA., Standard methods for examination of water and waste water 15th Ed. American pub. Health Asso., Washington D.C(1995)2.BIS., Bureau of Indian Standards, IS:10500-91,Manak Bhavan, New Delhi, India (1998) 3.Brindha K. and Elango L., Study on bromide in groundwater parts of Nalgonda district, Andhra Pradesh, Earth Sci India., 73-80 (2010)4.CGWB., Groundwater quality in shallow aquifers of India, Faridabad, Central Groundwater Board, Ministry of Water Resources, Govt of India (2010) 5.CGWB., Groundwater In: Proceddings of 3rd National Water Commission, Nagpur, India, Central Ground Water Board, Govt of India (1992) 6.Eaton F.M., Significance of carbonates in irrigation water., Soil Sci,69 123-133 (1950)7.Gibbs R.J., Mechanisms Controlling World’s Water Chemistry, Science, 170 1088-1090 (1970)8.Ghosh N.C. and Sharma K.D., Groundwater modeling and management, New Delhi (2006)9.Hem J.D., Study and interpretation of the chemical characteristics of natural water, Scientific publishers, Jodhour, India (1991)10.Mills B., Interpreting water analysis for crop and pasture. File No. FS0334, DPI’s Agency for Food and Fibre Sciences, Toowoomba (2003)11.Murhekar Gopalkrishna H., Assessment of physico Chemical status of Groundwater samples in Alkot city, Res. J. Chem.Sci., 4 117-124 (2011)12.Piper A.M., A graphical procedure in the geochemical interpretation of water analyses, Trans Amer. Geophy. Unio., 25 914-928 (1944)13.Raghunath H.M., Groundwater, New Delhi, Wiley (1987)14.Ramesh K. and Elango L. Groundwater quality assessment in Tondiar basin, Ind. J. Environ. Prot., 26 (6) 497-504 (2005)15.Richards L.A., Diagnosis and improvement of saline and alkaline soils, U.S. Dept. of Agriculture (1954)16.Singh K.P., Malik D., Singh V.K. and Sinha S., Evaluation of groundwater quality in Northern Indo-Gangetic alluvium region, Env. Monit. Assess.,112 211-230 (2006)17.Sivanappan R.K., Expansion of storage capacity, critical.In;Ravi.N (ed), Survey of Indian Agriculture, The Hindu, India., (2002) I Research Journal of Environment Sciences________________________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 23 18.Soltan M.E., Characterization, classification and evaluation of some groundwater samples in upper Egypt, J.Chemosphere., 37 735-745 (1998)19.Todd D.K., Groundwater hydrology, Wiley, New York (1980)20.WHO., Guidelines for drinking water quality, World Health Organization, Geneva (1984)21.Wilcox L.V., Classification and use of irrigation water, U.S. Dept. of Agriculture (1955) Table-1 Groundwater samples of study area exceeding the permissible limits prescribed by BIS for domestic purposes Parameters Pre monsoon (August 2011) Post monsoon (February 2012) BIS standards (1998) Permissible limit Maximum limit pH 6.9 – 7.9 6.8 – 7.9 6.5-8.5 6.5-9.2 EC 100 – 2620 80 – 5300 - - TDS 70 – 1834 53 – 3392 500 1000 Ca 2+ 10 – 140 40 – 150 75 200 Mg 2+ 6 – 84 14 – 100 30 70 Na + 45 – 114 49 – 141 50 200 K + 0.5 – 19.2 0.18 – 26.3 - - HCO 3 - 136 – 480 125 – 460 30 Cl - 7.5 – 542 9 – 1490 250 1000 SO 4 2 - 8 – 200 10 – 180 200 400 NO 3 - 1 – 12 4 – 21 45 No relaxation F - 0.2 – 2.8 0.2 – 2.6 1.0 1.5 TH 50 – 700 53 – 800 300 600 Units of all parameters are in mg/l except EC(S/cm ) and pH Table-2 Groundwater classification according to base-exchange index () and Meteoric genesis index () criteria for premonsoon and postmonsoon seasons Premonsoon- Water Types Postmonsoon- Water Types Sample no Base-exchange index (r 1 ) Meteoric genesis index (r 2 ) Base-exchange index (r 1 ) Meteoric genesis index (r 2 ) 1 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 2 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 3 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 4 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 5 Na + - HCO 3 - Shallow meteoric Na + - HCO 3 - Shallow meteoric 6 Na + - HCO 3 - Shallow meteoric Na + - HCO 3 - Shallow meteoric 7 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 8 Na + - HCO 3 - Shallow meteoric Na + - HCO 3 - Shallow meteoric 9 Na + - SO 4 2 - Deep meteoric Na + - SO 4 2 - Deep meteoric 10 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 11 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 12 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 13 Na + - SO 4 2 - Deep meteoric Na + - SO 4 2 - Deep meteoric 14 Na + - SO 4 2 - Deep meteoric Na + - SO 4 2 - Deep meteoric 15 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 16 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 17 Na + - HCO 3 - Shallow meteoric Na + - HCO 3 - Shallow meteoric 18 Na + - SO 4 2 - Deep meteoric Na + - SO 4 2 - Deep meteoric 19 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 20 Na + - SO 4 2 - Shallow meteoric Na + - HCO 3 - Shallow meteoric 21 Na + - SO 4 2 - Deep meteoric Na + - SO 4 2 - Deep meteoric 22 Na + - SO 4 2 - Shallow meteoric Na + - HCO 3 - Shallow meteoric 23 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 24 Na + - SO 4 2 - Deep meteoric Na + - SO 4 2 - Deep meteoric 25 Na + - SO 4 2 - Deep meteoric Na + - SO 4 2 - Deep meteoric 26 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 27 Na + - HCO 3 - Shallow meteoric Na + - HCO 3 - Shallow meteoric 28 Na + - HCO 3 - Shallow meteoric Na + - HCO 3 - Shallow meteoric 29 Na + - SO 4 2 - Deep meteoric Na + - HCO 3 - Shallow meteoric 30 Na + - SO 4 2 - Deep meteoric Na + - SO 4 2 - Deep meteoric I Research Journal of Environment Sciences________________________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 24 INDIA TAMIL NADU THENI DISTRICT 0.51.52.5VadapudhupattiLakshmipuramSarathu pattiThamaraikulamThenkaraiKeelavadakaraiE.PuthukottaiMurugamalaiEndapuliKamatchipuramThevathanapatti 1Thevathanapatti 2GenguvarpattiG.KallupattiEluvanampattiT.VadipattiSilvarpattiErumalainaickenpattiBomminayanpatti 1Bomminayanpatti 2A.Vadipatti 1A.Vadipatti 2Marugalpatti 1Marugalpatti 2Gullapuram 1Gullapuram 2MuthalakampattiJeyamangalamMelamangalamVadugapattiFluoride (mg/l) Premonsoon Postmonsoon Figure-1Location of the Study Area with Sampling Wells Figure -2: Concentration of Fluoride groundwater samples I Research Journal of Environment Sciences________________________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 25 Figure -3: Piper trilinear diagram for groundwater samples Figure-4 Gibbs diagram for groundwater samples Figure-5 Salinity index for groundwater samples I Research Journal of Environment Sciences________________________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 26 Figure-6 Chlorinity index for groundwater samples Figure-7 Sodicity index for groundwater samples Figure-8 Wilcox diagram for groundwater samples I Research Journal of Environment Sciences________________________________________________ I Res. J. Environment Sci. Vol. 1(1), 19-27, August (2012) International Science Congress Association 27 Figure -9 RSC values for groundwater samples