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Gondwana Geological Magazine Special Volume No.14, 2014, pp. 155-160 GGM www.ggsnagpur.org Hydrogeochemistry of Groundwater in Koradi-Khaparkheda area, Nagpur District, Maharashtra 1 2 1 R.A. Rathod, R.K. Bopche, P. Kundal * 1 PG Department of Geology, RTM Nagpur University, Law College Square, Nagpur-440 001, India 2 Department of Civil Engineering, Kavikulguru Institute of Technology and Science, Ramtek-441 106, India *E-mail: pradeepkundal@gmail.com Abstract Groundwater being the largest available source of fresh water lying beneath the ground, its role in domestic, agricultural and industrial development has increasingly been recognized. The present study deals with the seasonal variations in hydrogeochemistry of groundwater in Koradi-Khaparkheda area, based on the selected dugwell samples. Fifteen groundwater samples were collected and analyzed for physicochemical parameters. Chemically, the groundwater of the pre-monsoon and post-monsoon samples are dominated by alkaline earths and weak acids and indicates fresh water type as revealed from Piper trilinear diagram. The higher value of NO is reported in few dugwells in the study area. 3 Keywords: Hydrogeochemistry, Iso contour map, Koradi-Khaparkheda, Thermal Power Station, Nagpur District, Maharashtra. Introduction Groundwater resources are dynamic in nature as they grow with the expansion of urbanization, irrigation and industrialization etc. The Koradi-Khaparkheda area is located about 15 km north of the Nagpur city (Fig.1). Koradi- Khaparkheda is well known for the Thermal Power Station (TPS). The Koradi-Khaparkheda thermal power station supplies power to the eight districts of Vidarbha region. The 0 0 0 0 study area lies between 21 12' to 21 17'N and 79 5' to 79 10'E and it covers an area of about 59 sq km. The sampling of groundwater was done in pre-monsoon and post-monsoon in selected fifteen dug wells, based on different lithology. The present study deals with the hydrogeochemistry of groundwater from the Koradi-Khaparkheda area. Geology of Study Area Precambrian (Archaeans) crystalline rocks which are exposed in the area are belonging to the Sausar Group comprising meta-sedimentary and meta-basic rocks closely associated with large number of intrusive bodies (Gwalani et al., 1999). The rocks are mainly quartz mica schist, quartzite, marble, amphibolite, granite gneiss and pegmatites rocks (Fig.2). These rocks of Sausar Group were subjected to intense tectonic activities during the Proterozoic period (Bopche, 1997) which is followed by folding, faulting and intrusive bodies which comes along weak zones. Lower Gondwana Group comprises Talchir, Barakar and Kamthi Formations. The sandstone with shale bands of the Talchir Formation are exposed north-east part of the study area, which is having 0 0 strike NE-SW with dips of 15 to 20 due SW to SSW. Geomorphology The area is undulating to flat region into which a few broad valleys like Khanhan and Kolar rivers and small streams and ponds are present. The highest elevation is at Suradevi hills 384m (MSL) whereas the lowest elevation is found river bed 260m (MSL). The streams flow from northeast to southwest direction. The groundwater flow direction follows the topographical gradient. Hydrogeology Groundwater at shallower depth occurs under unconfined and deep groundwater occurs under phreatic condition in the study area. The Precambrian crystalline rocks are hard and compact and they have secondary porosity like jointing and fracturing. The ability of these crystalline rocks to store, transmit and yield groundwater depends on the degree of weathering and intensity of joints and fracturing of the

156 R.A. Rathod et al. Nagpur Fig.1. Location map of study area Fig.2. Geological map of the Koradi-Khaparkheda area with dugwell sample location (modified after Gwalani et al., 1999) formation (Subramanian et al., 1996). An examination of the sections exposed in the dug wells and road cuttings at places indicate that the zone of weathering extends down to the depth of about 10-15m below ground level in the study area. The pegmatite rock is characterized by presence of essential minerals like plagioclase and oligoclase feldspar and accessory minerals like muscovite and biotite, hornblende and augite. The feldspars contain sodium, potassium and calcium, aluminium, silicon and oxygen. The accessory minerals contain fluoride (Pujari et al., 2005). Fluoride is reported from several pegmatitic minerals like biotite, muscovite and apatite, which is stable during weathering (Duraiswami et al., 2011). The Kamthi Sandstones are most potential aquifers as they are highly porous and permeable due to presence of primary porosity and permeability of rock. The sandstone has covered the northeastern part of the study area. The site for dug wells for the study is selected on the basis of lithology (Fig 2). Methodology From the selected dug wells representing district

Hydrogeochemistry of Groundwater in Koradi-Khaparkheda area 157 lithology of the study area, fifteen samples of groundwater were collected in one litre polyethylene bottles during premonsoon and post-monsoon seasons in the month of May and December 2010. The samples were analyzed for different elemental concentrations viz. TDS, total alkalinity, Cl, SO, F, 4 Ca, Mg, Total Hardness, K, Na, NO, CO, HCO etc. The 3 3 3 groundwater analysis was done from the Hydrology Project Division, Level-II in Nagpur. The parameters like ph and EC were measured in the field itself with the help of field instruments like ph meter and electrical conductivity meter. The various physico-chemical parameters of water samples were analysed and the results are plotted in the form of graphs, Iso- contours map and piper's trilinear diagrams. Physical Characteristics of Groundwater Electrical conductivity (EC) It is a measure of water capacity to conduct electric current. As most of the salts in the water are present in the ionic form, so they are responsible to conduct electric current. Generally, groundwater tends to have high electrical conductivity due to the presence of high amount of dissolved salts. The conductivity of electricity through the solution is related to the concentration of ions, their electric charges and their mobilities. Specific conductance is expressed in mhos/cm. It is such a large unit that, most natural waters have a o value much less than 1 unit at 25 C. Here values range from 512 to 2380 micromhos/cm in pre-monsoon and in post-monsoon values range from 570 to 1604 micromhos/cm (Table 1). Total Dissolved Solid (TDS) It is numerical sum of all dissolved solids determined accurately by chemical analyses. In general, acceptance level is 500mg/l but, World Health Organization (WHO, 1997) has set allowable limit of 1500 mg/l. In the study area, TDS content varies from 316 to 1404 mg/l (pre monsoon) and 360 to 1018 mg/l (post-monsoon). The results indicate the seasonal variation of TDS values with respect to different depth. Iso-pH It is a measure of hydrogen ion concentration. The ph value of water is indication of acidic or basic nature the water countable on the scale of 0 to 14. The groundwater is usually near alkaline here with ph varying from 7.3 to 8.5. The Isocontour map showing lines of equal concentration of ph value. pre-monsoon and post-monsoon maps as shown in Fig.3, indicates that as water increases during post-monsoon the water tends to get neutralized, that is for ph>7 values fall to near 7 and for ph<7 the values rise to 7. The ph value in pre monsoon varies from 7.4 to 8.5 and post monsoon varies from 7.3 to 8.4 in the study area. Iso-Hardness Hardness in water is caused by certain salts held in solution. The most common are the carbonates, fluorides and sulphates of calcium and magnesium. The general acceptance level of hardness is 300 mg/l. But WHO (1997) has set allowable limit of 600 mg/l. In the study area, hardness varies from 204 mg/l to 1150 mg/l. It is within limit everywhere except in the Suradevi village, sample no. KK 3 having more than 1000 mg/l and 5 and 11 above 600 mg/l in pre-monsoon indicating very hard water. The Iso-contours map showing lines of equal concentration of hardness value, pre- and postmonsoon maps as shown in Fig 4. The pre-monsoon value Table 1: Comparison of groundwater quality parameters with drinking water standards Sr.no. Parameter BIS (1991) Analysed Samples No. of samples beyond desirable limit Pre monsoon Post monsoon Pre-monsoon Post-monsoon 1 EC >1500 512-2380 570-1604 4 1 2 ph 6.5-8.5 6.6-8.5 7.3-8.4 0 0 3 TDS 500 316-1404 360-1018 10 9 4 Alkalinity 200 208-532 212-642 15 15 5 Chloride 250 10-315 24-260 1 1 6 Sulphate 200 2-222 27.9-205.4 2 1 7 Fluoride 0.6-1.0 0.4-0.7 0.39-0.91 0 0 8 Total Hardness 500 236-1150 204-880 5 5 9 Calcium 500 46.5-328.7 22-123.1 0 0 10 Magnesium 30 12.6-92.3 23.3-120.4 8 14 11 Sodium 100 6.2-268 20-192 5 1 12 Potassium 10 0.7-3.2 0.6-7.8 0 0 13 Nitrate 45 1.24-10.72 0.45-46.69 0 1 14 Carbonate - 0.9-3.3 0.3-3.5 - - 15 Bicarbonate 300 204.6-532 208.5-642 6 8 All ions in mg/l; EC in micromhos/cm

158 R.A. Rathod et al. Fig.3. Iso-pH contour map A) Pre-monsoon B) Post-monsoon varies from 236 to 1150 mg/l and post-monsoon value varies from 204 to 880 mg/l in the study area. Iso-Alkalinity contour map It is a measure of acid-neutralizing capacity of water. The alkalinity of groundwater is mainly due to carbonate and bicarbonate in the water. The Alkalinity value in pre monsoon varies from 208 to 396 mg/l and post monsoon values varies from 212 to 642 mg/l in the study area. The BIS acceptable limit is 200 mg/l and permissible limit up to 600 mg/l (Table1). The Iso-contours map showing lines of equal concentration of alkalinity values. The higher values of alkalinity in north western part of the study area in pre and post monsoon season (Fig.5). Chemical Characteristics of Groundwater Nitrate content ranges from 1.24 to 10.72 mg/l in pre monsoon and 0.45 to 46.69 mg/l in post monsoon (Table 1). The Post monsoon value of Nitrate is high as compared to pre monsoon values. The high content of NO 3 indicates the excessive use of chemical fertilizer in the agricultural fields as well as discharge of domestic sewage combined with industrial wastewater (Marghade, 2009). Fluoride content varies from 0.4 to 0.7 mg/l in pre monsoon and 0.39 to 0.99 mg/l in post monsoon. The post monsoon value of fluoride is high as compared to pre monsoon values (Table 1). It is observed that high fluoride concentration in post monsoon groundwater sample is associated with high sodium-bicarbonate-iron affinity with elevated ph values (i.e. Fig.4. Iso-Hardness contour map A) Pre-monsoon B) Post-monsoon

Hydrogeochemistry of Groundwater in Koradi-Khaparkheda area 150 Fig.5. Iso-Alkalinity contour map A) Pre-monsoon and B) Post-monsoon > 7.0) and relatively low magnesium (Routroy et al., 2013). High concentration of fluoride is due to ph, solubility of fluoride bearing minerals, ion exchange capacity of aquifer - materials (OH and halogens) and geological formations drained by water and accordingly the contact time of groundwater with a particular formation. Piper's trilinear diagram The Piper's (1944) diagram consists of two lower triangular fields and a central diamond shaped field, where all the three fields have scale reading in 100 parts. The percentage reacting values of the cations and anions are plotted as a single point (according to trilinear coordinates) at the lower left and right triangles, respectively. The water quality types can be easily identified by the location of points in the different zones of the diamond-shaped field as shown in Fig.6. The pre monsoon and post monsoon groundwater sample points fall under fresh groundwater in piper diagram (Todd, 1980; Karanth, 2010). The chemical composition of the groundwater is dominated by the alkaline earths and weak acids. The most of the groundwater samples fall in the field of CaMgHCO 3 types. Conclusions Groundwater quality deterioration is the main concern of the study area, as it is caused due to increased power generation industries, rapid urbanization and improper water management. The concentration of the ions in the studied groundwater samples exceeds the BIS 1991 limits. The ph of the groundwater samples during both the Pre-monsoon Fig.6. Piper's trilinear diagram a) pre-monsoon b) post-monsoon Post-monsoon

160 R.A. Rathod et al. seasons are within the permissible limit. The Post monsoon value of Nitrate is high as compared to pre monsoon values. The high content of NO 3 indicates the excessive use of chemical fertilizer in the agricultural fields as well as discharge of domestic sewage and industrial wastewater. The results reveals that dug wells are polluted and should be protected by constructing raised concrete rings around the dug wells. The groundwater of the pre-monsoon and postmonsoon samples dominated by alkaline earths and weak acids and indicate fresh water type as revealed from Piper's trilinear diagram. Acknowledgements Authors are grateful to Hydrology Project Division, Level-II analysis lab for the analyses and Mrs. Yogita Badge for constant help during entire study. The author (RAR) is a bonafied Ph.D student of R.T.M Nagpur University, Nagpur and the present paper is an outcome of his ongoing research work. We are also thankful to Head, P.G. Department of Geology, R.T.M Nagpur University for providing lab facility. Authors are deeply indebted to the anonymous reviewers for critical reviewing. References Bopche, R. K. (1997). Geohydrology around Ramtek, Nagpur district, Maharashtra, Indian Water Works Association, pp.275-295. BIS (1991) Drinking water specification, Bureau of Indian Standards New Delhi, 8p. Duraiswami, R. A. and Patankar, U.R. (2011). Occurrence of fluoride in the drinking water sources from Gad River basin, Maharashtra. Jour. Geol. Soc. India, v..77,pp.167-174. Gwalani, L.G., Dalal, V.P., Soledad Fernandezs, Mulai, B.P., Shireen Praveen and Shastry, B.V. (1999). Granitic Pegmatites of Koradi- Kolar sector, Nagpur district, Central India: Field, Petrographic and Minerological Features. Revista Brasileira de Geociencias, v.29(1),pp.99-104. Karanth, K.R. (2010). Groundwater assessment development and management. Tata McGraw Hill Education Pvt. Ltd., New Delhi. Marghade, D. (2009). Assessment of Nitrate pollution and vulnerability of groundwater of Pili nadi area of Nagpur City, Central India, Workshop on Groundwater resource management in Maharashtra, Proceeding, CGWB, Central Region, Nagpur, pp.174-178. Piper, A.M. (1944). A graphic procedure in the geochemical interpretation of water analyses, Trans. Amer. Geophys. Union, v.25,pp.49-56. Pujari, P. R. and Deshpande, V. (2005). Source apportionment of groundwater pollution around landfill site in Nagpur, India. Jour. Environ. Monit. Assess., v.111,pp.43-54. Routroy, S., Harichandan, R., Mohanty, J.K., and Panda, C.R. (2013). A statistical appraisal to hydrogeochemistry of fluoride contaminated groundwater in Nayagarh District, Odisha. Jour. Geol. Soc. India, v.81,pp.350-360. Subramanian, P. R., Shireen Praveen, Shastry, B.V. and Gwalani, L.G. (1996). Hydrogeologic features of Nagpur city in the Vidarha Region of Maharashtra. Mineral and Groundwater Resources of Vidarbha. Golden Jubilee Symp.Volume, pp. 235-242. Todd, D.K. (1980). Ground Water Hydrogeology, John Wiley and Sons. nd WHO (1997). Guidelines for Drinking water quality, 2 edition, v.1., recommendation, WHO, Geneva.