Appl Water Sci DOI 10.1007/s13201-015-0312-0 ORIGINAL ARTICLE Assessment of fluoride contaminations in groundwater of hard rock aquifers in Madurai district, Tamil Nadu (India) 1 1 2 1 3 C. Thivya • S. Chidambaram • M. S. Rao • R. Thilagavathi • M. V. Prasanna • S. Manikandan1 Received: 19 February 2015 / Accepted: 7 July 2015 Ó The Author(s) 2015. This article is published with open access at Springerlink.com Abstract The fluoride contamination in drinking water is fluoride bearing minerals in groundwater. The higher already gone to the alarming level and it needs the concentration of fluoride ions are observed in the lower EC immediate involvement and attention of all people to solve concentration. The isotopic study suggests that fluoride is this problem. Fluoride problem is higher in hard rock ter- geogenic in nature. In factor scores, fluoride is noted in rains in worldwide and Madurai is such type of hard rock association with pH which indicates the dissolution region. Totally 54 samples were collected from the process. Madurai district of Tamilnadu with respect to lithology. The samples collected were analysed for major cations and Keywords Groundwater Á Fluoride Á Lithology Á anions using standard procedures. The higher concentration Weathering of fluoride is noted in the Charnockite rock types of northern part of the study area. 20 % of samples are below 0.5 ppm and 6 % of samples are above 1.5 ppm exceeding Introduction the permissible limit. The affinity between the pH and fluoride ions in groundwater suggests that dissolution of The highly reactive fluorine exists in the form of fluoride in natural waters (Leung and Hrudey 1985). Fluoride is a naturally occurring element in groundwater which origi- & M. V. Prasanna nates mainly from the natural sources and causes signifi- [email protected] cant health impacts. The recommended value of fluoride in C. Thivya drinking water prescribed by the WHO (2008) standard is [email protected] 1.5 mg/l. Fluorosis is said to be a worldwide problem. It S. Chidambaram has been reported that nearly 20 developing countries [email protected] (Mameri et al. 1998) and 17 states in India (Yadav and M. S. Rao Khan 2010) are affected by fluorosis including Tamilnadu. [email protected] It is estimated that 200 million peoples in the world R. Thilagavathi of 20 countries are affected by this endemic disease and in [email protected] Indian continent 62 million peoples are affected from flu- S. Manikandan orosis from the drinking of fluoride rich water. 150,000 [email protected] villages in India are affected by the dental fluorosis prob- lem. It plays a vital role in the formation of dental enamel 1 Department of Earth Sciences, Annamalai University, Annamalai Nagar 608002, India and normal mineralization of bones when it is present in less quantity (Chouhan and Flora 2010). Fluoride health 2 National Institute of Hydrology, Roorkee 247667, Uttarakhand, India problems are common in semi-arid regions in many countries (Jacks et al. 2005; Reddy et al. 2010). The fluo- 3 Department of Applied Geology, Faculty of Engineering and Science, Curtin University, Sarawak Malaysia, CDT 250, ride concentration less than 0.5 mg/l leads to the risk of 98009 Miri, Sarawak, Malaysia tooth decay (Abu-Zeid 1998) and the concentration above 123 Appl Water Sci 1.5 mg/l causes the endemic disease called dental fluorosis amphiboles with OH, F group and they are mostly observed (Handa 1975; Ripa 1993).The primary adverse effects in the Igneous and Metamorphic rocks (Chidambaram associated with chronic, excess fluoride intake are dental 2000; Manikandan et al. 2012). Many people suffer from and skeletal fluorosis (Susheela 1993). Fluoride in the fluorosis in the world due to the intake of fluoride rich groundwater is mainly controlled by local and regional groundwater (Zhang et al. 2003) and in the study area the geology, lithology and their flow directions and also they groundwater is the main sources of drinking water. Keep- are aided by semi-arid climate of the region (Umarani and ing these factors in mind an attempt has been made to ramu 2014; Saxena and Saxena 2014). Fluoride content in identify the sources of fluoride, its distribution in ground- groundwater is mainly due to natural contamination, but water with respect to lithology to categorise the fluoride the process of dissolution is still not well understood (Ripa affected areas spatially and to delineate the interrelation- 1993; Saxena and Ahmed 2001).The higher fluoride in the ship of fluoride with other major ions in groundwater. groundwater of hard rock regions have been carried out by various researchers (Chidambaram et al. 2013; Manivan- nan et al. 2012; Singaraja et al. 2012; Manikandan et al. Study area 2012).Weathering of minerals and formation of Calcium and Magnesium carbonates serves the good sinks for the General details fluoride in groundwater (Srinivasamoorthy et al. 2008). In Bakreswar and Birbhum regions of west Bengal fluoride The study area lies in the north latitude of 9°3303.600 and contamination arise by industrial pollution from the man- 10°1908.400 and east longitude of 77°2707.200 and ufacture of steel, aluminium and fertilizers, whereas fluo- 78°28058.800 covering an 3741 km2 in southern part of rapatite is used as a source of phosphorous (Datta et al. Tamilnadu (Fig. 1). There are seven taluks in this district 2014). The usage of phosphatic fertilizer into the soil in namely Madurai-North, Madurai-South, Melur, Vadipatti, agricultural activities also causes potential fluoride in Usilampatti, Peraiyur and Thirumangalam. The major river groundwater (Loganathan et al. 2006). system that feeds the Madurai is Vaigai river basin which The fluoride concentration in groundwater of the sur- separates the district into two parts. The average rainfall of rounding districts of Madurai like Dindugal (Manivannan this district is 902 per annum. The topography of the area 2010), Tiruchirapalli (Ramesh et al. 2012), Sivaganga ranges between 160 and 1400 m above mean sea level (CGWB 2010) have also been the earlier studies shows that (Sankar 2002). More than 85 % of the soil in this district is certain location of Madurai district is also reported to have classified as red soil. The study area experiences a semi- high fluoride (CGWB 2008) [1.5 ppm. It is also under- arid climate (CGWB 2008). Madurai is one of the few stood that there is continuation of lithology from the sur- rubber growing areas in South India and there are rubber- rounding district and moreover hard rock terrains are based industries. commonly reported to have high concentration of fluoride in groundwater (Chidambaram 2000). The increase of Lithology temperature and the quantity of water consumed are also the main causes of fluorosis in the other part of the study The lithology comprises fissile hornblende biotite gneiss, area (Manivannan et al. 2012; Chidambaram et al., 2013). charnockite, granites, quartzites and floodplain alluvium The higher concentration of fluoride in India has been along the river (GSI 1995). Madurai district falls in the resulted due to the dissolution of fluorite, apatite, micas, southern granulite terrains. Massive Charnockite of Fig. 1 Study area map with lithology and sampling points 123 Appl Water Sci Fig. 2 Water level map of the study area (in meters above mean sea level) comparatively high mafic appearance are observed in this samples. Then, it was sealed and brought to the laboratory terrain (Srikantappa et al. 1985). Mafic Charnockite (two for analysis, stored properly (4 °C) and filtered with pyroxene granulite) having major mineral assemblage of 0.45 lm filter paper before analysis. The pH and TDS were clinopyroxene, orthopyroxene, hornblende and plagioclase. determined in the field using the field kit (Eutech handheld The khondalite shows a general mineralogy of K feldspars, instruments). quartz, garnet, biotite, sillimanite, cordierite, spinel and plagioclase, with graphite, apatite and zircon as major Fluoride ion analysis accessories (Baiju 2006). Fluoride (F-) concentration was determined using Orion Water level fluoride ion electrode model (94-09, 96-09). The instru- ment was checked for slope by TISAB III (concentrate The entire district is mainly covered by the hard rock with CDTA) using the metre with millivolt read only mode regions and the groundwater occurs in the weathered part (APHA, 1995; Manikandan et al. 2012). The electrode is of the hard rocks, fractures, fissures and joints (CGWB rinsed with distilled water, blot dry and placed into the 2007). The aquifers range from Archaean to Recent allu- beaker. When the stable reading is displayed, the mv values vium. The ground water level in this district varies for the corresponding standard concentration (0.05, 0.1, 1, according to the formation of rocks. The reduced water 1.5, 2.5, 5, 10, and 100 ppm) were noted. 50 ml of more level with respect to sea level is shown in figure (Fig. 2). concentrated standard and 5 ml of TISAB III was taken, The figure shows that the greater levels of depth to water stirred thoroughly and the readings were measured. The table were noted in the southern and the northern/north- electrode was rinsed with deionized water, blot dry and eastern part of the study area. It also indirectly indicates place into the second beaker—where stable reading was that the ground water moves towards the eastern part of the displayed, then mv value was recorded and corresponding study area. The deepest groundwater level is noted along standard concentration was plotted in semi logarithmic the Vaigai river. graph paper. Later calibration curve was prepared by plotting the mv values on the linear axis, and the standard concentration values on the logarithmic axis. 50 ml of Methodology sample was taken with 5 ml of TISAB III, stirred thor- oughly.