Assessment and Spatial Distribution of Quality of Groundwater in Zone II and III, Greater Visakhapatnam, India Using Water Quality Index (WQI) and GIS

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1 Assessment and Spatial Distribution of Quality of Groundwater in Zone II and III, Greater Visakhapatnam, India Using Water Quality Index (WQI) and GIS Swarna Latha.P 1, Nageswara Rao.K 2 1 Department of Geography, Andhra University, Visakhapatnam Department of Civil Engineering, GIT, GITAM University, Visakhapatnam dr.swarnapisupati@gmail.com ABSTRACT Assessment and mapping of quality of groundwater is an important quantity, because the physical and chemical characteristics of groundwater determine its suitability for agricultural, industrial and domestic usages. The present study appraises the groundwater quality of Greater Visakhapatnam, Zone II and III areas with the estimation of water quality index and coupled with GIS technology. Inverse distance weighted (IDW) raster interpolation technique of spatial analyst module in ArcGIS software has been used to generate the spatial distribution of water pollutants of constituents. Based on the analysis, most of the area under study falls in moderately polluted to severely polluted zone. The results revealed that the groundwater was not suitable for drinking purpose in most of the areas due to the influence of sewage, saltwater intrusion, industrial and high urban concentration. Keywords: Spatial distribution, Groundwater quality, Greater Visakhapatnam, Geographical Information System (GIS) 1. Introduction In 2005, the Andhra Pradesh (A.P) state government has upgraded the Visakhapatnam Municipal Corporation (VMC) to Greater Visakhapatnam Municipal Corporation (GVMC), called as Greater Visakhapatnam, merged along with Gajuwaka municipality and 32 gram panchayats. Its area of jurisdiction has expanded merely from 111 sq. km to 535 sq. km encompassing sprawling suburbs. The total population was increased from one million to about 1.5 million (VUDA, 2003). The Greater Visakhapatnam, situated on the east coast of India (17º 32' N to 17º 51' N latitudes and 83º 05' E to 83º 24' E longitudes), is one of the prime urban corridor and major sprawling industrial city in A.P and one of the fastest growing cities in Asia (Figure 1). Due to the rapid growth of urbanization and industrialization, there is an increasing pressure on land, water and environment, particularly like these metropolitan cities. Concentration of human population in urban areas has resulted in increase of buildings, roads, vehicles, factories, urban sewage and storm drains, smoke and dust, and garbage hazards which leads to severe water and air pollution (Subba Rao et al., 1997; Swarna Latha and Nageswara Rao, 2007). Assessment of quality of groundwater through water quality index (WQI) studies, spatial distribution mapping for various pollutants utilizing GIS technology and the resulted information on quality of water could be useful for policy makers to take remedial measures (Nageswara Rao et al., 2007; Pradhan et al., 2001; Swarna Latha et al., 2007). GIS can be a powerful tool for developing solutions for water resources problems to assess in water quality, determining water availability, understanding the natural environment on a local and/or regional scale. The Zone II & III of Greater Visakhapatnam located between 17º 41' 30'' N to 17º 45' N latitudes and 83º 17' 30'' E to 83º 21' E longitudes is chosen for the present study due to the higher degree of concentration of urban activities occurred in this region. Keeping this in view for the area under study we have carried out the physico chemical analysis for various parameters of groundwater 198

2 for domestic use and development of WQI, and mapping of their spatial distribution using GIS techniques. 2. Methodology The overall methodology adopted for the present study is presented in the form of flow chart in Figure Geo database Sampling was carried out during pre and post monsoon seasons for the year 2006 using GPS survey. A total of twenty four water samples were collected from the selected locations throughout the study area (Figure 1). The graticules and altitude values of the selected sampling locations are given in Table 1. The collected samples were preserved by adding appropriate reagents in laboratory to determine the water quality analysis. These samples were analyzed for different parameters (Table 2) following standard methods (APHA, 1998). All the parameters were compared with the guidelines Figure 1: Map showing location and sampling points collected in the study area 199

3 suggested by Bureau of Indian Standards (BIS, 2003). The obtained water quality data form the attribute database which is used to generate the spatial distribution maps for the present study area Interpolation GIS model Inverse distance weighted (IDW) raster interpolation technique of spatial analyst module in ArcGIS (version 9.0) software has been used for the present study to delineate the locational distribution of various water pollutants. The different locations of the sampling stations were imported into GIS software through point layer. Each sample point was assigned by a unique code and stored in the point attribute table. The data base file contains values of all chemical parameters in separate columns along with a sample code for each sampling station. The geo database was used to generate the spatial distribution maps of selected water quality parameters namely alkalinity, total dissolved solids (TDS), total hardness (TH), chlorides (Cl), fluorides (F) and water quality index (WQI) Water Quality Index (WQI) Estimation WQI is computed to reduce the large amount of water quality data to a single numerical value. WQI reflects the composite influence of different water quality parameters on the overall quality of water. Water quality index was computed by adopting the method of Tiwari and Mishra (1985), Sinha and Saxena (2006) to determine the suitability of the groundwater for drinking purposes as follows, Where w i = weightage factor of i th parameter q i = quality rating of i th parameter w i is calculated from the following equation, w i = k/s n s n = standard value of i th parameter q i is calculated from the following equation, Where v a = actual value obtained from laboratory analysis of i th parameter v s = standard value of i th parameter v i = ideal value (ph=7 and 0 for all parameters) Figure 2: Flow chart showing the process flow 200

4 Based on the water quality index, the analyzed samples were grouped into three categories namely suitable for drinking (below 50), moderately polluted (51 to 80) and severely polluted (above 80). Table 1: Details of sampling locations of the study area Sl. no Sampling station Lat. dms Long. dms Alt. mts Sl. no Sampling station Lat. dms Long. dms Alt. mts 1. Muvalavanipalem Sitampeta Venkojipalem Dwarakanagar HB colony RTC complex Maddilapalem Ramnagar Peda Waltair R K beach Lawsons bay Jalaripeta Eastpoint colony I town China Waltair Soldierpet Balajinagar Poornamarket Resapuvanipalem Maharanipeta Sitammadhara Dabagardens Akkayyapalem Allipuram Lat.: Latitude, Long.: Longitude, Alt.: Altitude Table 2: Analytical methods adopted for physico chemical analysis Analysis Method/instrument ph Digital ph meter Alkalinity Titrimetry Electrical conductivity (EC) Digital conductivity meter Total dissolved solids (TDS) Indirect method (Raghunath, 2003) Total hardness (TH) & calcium hardness (CaH) EDTA Titrimetry Magnesium hardness (MgH) Indirect method (Todd, 2001) Sodium (Na) & Potassium (K) Flame photometer Iron (Fe) 1,10 phenanthroline Spectrophotometry Bicarbonates (HCO 3 ) + carbonates (CO 3 ) Indirect method (Hem, 1985) 1.31 Alkalinity Chlorides (Cl) Mohr s Titrimetry Sulphates (SO 4 ) Spectrophotometry Phosphates (PO 4 ) Ammonium molybdate method Spectrophotometry Fluorides (F) Selective ion meter 201

5 3. Results and Discussion 3.1. Groundwater quality variation The results obtained from the physico chemical analysis are presented in Tables 3 to ph The ph of a solution is the negative logarithm of hydrogen ion concentration in moles per litre. In premonsoon water samples, the ph varies from 7.0 to 8.31 while in the post monsoon water samples, it ranges from 7.0 to 8.1 indicating well permissible limits Alkalinity and Bicarbonates The alkalinity varies from 172 to 372 mg/l during the pre monsoon and ranges from 170 to 368 mg/l during post monsoon season. Dissolved carbondioxide, bicarbonate and carbonates produce alkalinity in water. Carbonates and bicarbonates are being estimated from the alkalinity values (Hem, 1985). Bicarbonates vary in the study area from to mg/l during pre monsoon season while in post monsoon water samples it ranges between and mg/l. More than 91% of the water samples in the study area contains alkalinity values higher than the desirable limit during pre monsoon, while in post monsoon it was observed that 83% of samples indicating above the limits. A perusal of alkalinity maps during pre and post monsoon seasons (Figures 3A1 and 3B1) showing the occurrence of low alkalinity at isolated pockets of the study area. The high alkalinity in the study area is increased due to the action of carbonates on the basic materials in the soil which gives an unpleasant taste to water Electrical Conductivity (EC) and Total Dissolved Solids (TDS) Electrical conductivity indicates the capacity of electrical current that passed through the water, which in turn is related to concentration of ionized substances present in it. Most dissolved inorganic substances present in the water are in ionized form and contribute to electrical conductivity. In the study area, electrical conductivity varies from 686 to 3552 µs/cm for pre monsoon water samples, while it ranges between 680 and 3600 µs/cm for post monsoon samples. Electrical conductivity of water is considered to be an indication of the total dissolved salt content (Hem, 1985). A rapid estimation of total dissolved solids content in water is obtained by EC. In the pre monsoon season, the mean values of TDS are varied from 439 to 2273 mg/l whereas during the post monsoon which ranges between 435 and 2304 mg/l. Except one sample (Sl.no 12), remaining all the water samples during both the seasons in the study shows above the limits of Indian standards (Figures 3A2 and 3B2). The almost of the area is not found suitable for drinking purpose owing to high TDS concentration, which is mainly due to seepage of surface water from open drains and their proximity to the industrial area and seacoast. TDS in groundwater can also be due to natural sources such as sewage, urban runoff and industrial wastes (Kurian, 2001; Swarna Latha, 2008). 202

6 Table 3: The analytical results showing quality of groundwater during pre monsoon season (2006) in the study area S.no ph Alkalinity EC TDS TH CaH MgH Na K Fe All parameters expressed in mg/l except ph and EC; where EC in µs/cm, ph has no units 203

7 Table 4: The analytical results showing quality of groundwater during pre monsoon season (2006) in the study area S.no HCO 3 Cl SO 4 PO 4 F WQI All parameters expressed in mg/l except ph and EC; where EC in µs/cm, ph has no units Total Hardness (TH) Total hardness is a measure of the capacity of water to the concentration of calcium and magnesium in water and is usually expressed as the equivalent of CaCO 3 concentration. In the present study, the total hardness of the pre monsoon waters ranges between 266 and 1152 mg/l, while it varies from 256 to 1134 mg/l in post monsoon waters. Ninety six percent of the area samples have more than 300 mg/l during both seasons falling under hard water category (Figures 3A3 and 3B3). In the absence of alternative source of water, the maximum permissible limit is 600 mg/l (BIS, 2003). In all 16% of total samples have hardness more than 600 mg/l are recorded at east and south, may be due to the natural accumulation of salts from contact with soil or it may enter from direct pollution by human activities. 204

8 Table 5: The analytical results showing quality of groundwater during post monsoon season (2006) in the study area S.no ph Alkalinity EC TDS TH CaH MgH Na K Fe All parameters expressed in mg/l except ph and EC; where EC in µs/cm, ph has no units 205

9 Table 6: The analytical results showing quality of groundwater during post monsoon season (2006) in the study area S.no. HCO 3 Cl SO 4 PO 4 F WQI All parameters expressed in mg/l except ph and EC; where EC in µs/cm, ph has no units Calcium Hardness (CaH) and Magnesium Hardness (MgH) Most of the geological material aquifers are composed of calcium. It was presented in groundwater as a material of suspension where calcium bicarbonate is the prime cause for the hardness in water. In groundwater the calcium content generally exceeds the magnesium content (CGWB, 2005). The values of both seasons showed that the calcium hardness was high in concentration for all the samples. The maximum CaH value has observed at Mindi (Sl.no: 21) and minimum value was at Narava (Sl.no: 12) same for both the seasons. Excessive calcium in drinking water is linked to the formations of concretions in the body and may cause gastro intestinal diseases and stone formations. The magnesium hardness of the pre monsoon waters ranges between 3.3 and 85.2 mg/l while it varies from 3.3 to 84.7 mg/l in post monsoon waters. 206

10 Figure 3: A1 to A6, spatial distribution of groundwater quality status showing for pre monsoon season in the study area 207

11 Figure 3: B1 to B6, spatial distribution of groundwater quality status showing for post monsoon season in the study area 208

12 3.1.6 Sodium (Na) Higher values of sodium are found in the groundwater in the areas of saline water intrusion. Discharge of effluents such as domestic and industrial etc. onto the ground is another source of sodium in water. In general sodium salts are not actually toxic substances to humans because of the efficiency with which mature kidneys excrete sodium. In the pre monsoon season, the mean values of sodium are varied from 34.3 to mg/l whereas during the post monsoon season which was ranges between 30.3 and mg/l Potassium (K) Potassium is slightly less common than sodium in igneous rocks, but more abundant in all the sedimentary rocks. Potassium is an essential element for plants and animals. The elements present in plant material and are lost from agricultural soil by crop harvesting and removal as well as leaching and runoff on organic residues. Potassium varies in the study area from 8.1 to 32.4 mg/l during premonsoon season while in post monsoon water samples it ranges between 7.9 and 30.4 mg/l Iron (Fe) Iron is biologically an important element which is essential to all organisms and present in hemoglobin system. Iron high concentration causes slight toxicity. The results showed that the concentrations of iron during both monsoons fall within the permissible limits of the study area Chlorides (Cl) Chloride concentrations vary widely in natural water and it directly related to mineral content of the water. It is known that the sea water intrusion is showing abnormal concentration of chloride. In potable water, the salt taste is produced by chloride concentrations. At concentrations above 250 mg/l, water acquires salty taste which is objectionable to many people. Bureau of Indian Standards prescribes 250 mg/l as permissible limit and 1000 mg/l as desirable limit in the absence of alternate source. The chloride concentration in the study area is less than 250 mg/l in 66% water samples and the remaining samples have less than 1000 mg/l which are recorded in pre monsoon season. Spatial distribution of chloride concentrations during pre and post monsoon seasons are shown Figures 3A4 and 3B4 respectively. The higher chloride content in groundwater may be attributed to the presence of soluble chloride from rocks and saline intrusion Sulphates (SO 4 ) The sulphate concentrations are varied from 44.6 to mg/l during pre monsoon season where as in the post monsoon season it ranges between 40.6 and mg/l. From the tables it can be observed that all the samples having sulphates value below 200 mg/l fall within the limits for both the seasons Phosphates (PO 4 ) Phosphorous, an essential nutrient for living organisms occurs in water as both dissolved and particulate species. It controls primary productivity. In the pre monsoon season the phosphates are varied from 0.01 to 1.4 mg/l whereas during the post monsoon which was ranges between 0.01 and 1.02 mg/l. 209

13 Fluorides (F) Fluoride is essential for human beings as a trace element and higher concentration of this element causes toxic effects. Concentration of fluoride between 0.6 to 1.0 mg/l in potable water protects tooth decay and enhances bone development (Kundu et al., 2001). Bureau of Indian Standards has suggested permissible limit of fluoride in drinking water at 1.0 mg/l and tolerance range is upto 1.5 mg/l. Ingestion of water with fluoride concentration above 1.5 mg/l results in fluorosis, dental mottling and bone diseases. In the study area, fluoride ranges between 0.6 and 1.2 mg/l of pre monsoon samples and in post monsoon water samples it was varied from 0.5 to 1.0 mg/l falls in desirable limits (Figures 3A5 and 3B5) WQI Analysis The values of selected parameters of groundwater quality data during pre and post monsoon seasons and BIS water quality standards were used for calculating water quality indices. The water quality standard values corresponding weightage factor and ideal values are presented in Table 7. Quality status is assigned on the basis of calculated values of water quality indices to include the collective role of various physico chemical parameters on the overall quality of drinking water. WQI computations were made from the equations and obtained results are given in Tables 3 to 6. The spatial distribution of the WQI map generated for the study area during pre and post monsoon seasons are presented in Figures 3A6 and 3B6. The results revealed that the groundwater two locations during pre monsoon and six locations during post monsoon season of the study area was in good quality of water where WQI ranges from 0 to 50 suitable for drinking purpose. The remaining area of samples are ranging between moderately polluted to severely polluted condition that may be due to the domestic sewage from open drains, sea water intrusion and industrial effluents from various industries. Table 7: The water quality standards, ideal value and weightage factors are considered to calculate the water quality index Parameter Standard S n and V s Ideal value V i ph Alkalinity TDS TH CaH MgH Cl SO F Weightage factor W i 210

14 4. Conclusions The study has demonstrated the utility of GIS technology combined with laboratory analysis in evaluation and mapping of groundwater quality in urban region. About 83% of the area under study comes under moderately polluted to severely polluted category revealed by the WQI studies. The two number of sampling locations in pre monsoon season and six locations in post monsoon season are only suitable for drinking purpose in the study. The spatial distribution maps generated for various physico chemical parameters using GIS techniques could be useful for planners and decision makers for initiating groundwater quality development in the area. 5. References 1. APHA, Standard methods for the examination of water and wastewater, American Public Health Association, Washington D.C., ArcGIS, GIS software, version 9.0, Environmental Systems Research Institute (ESRI), New York, BIS., Indian standards specifications for drinking water IS:10500, Bureau of Indian Standards, New Delhi, CGWB.,2005, Groundwater year book of Andhra Pradesh, Central Ground Water Board, Ministry of Water Resources, Govt. of India. 5. Hem,J.D.,1985, Study and interpretation of the chemical characteristics of natural water U.S. Geol. Surv. Water Supply Paper,2254,pp Kundu,N., Panigrahi,M., Tripathy,S., Munshi,S., Powell,M.A. and Hart,B.R.,2001,: Geochemical appraisal of fluoride contamination of groundwater in the Nayagarh district, Orissa, Environ. Geol.,41,pp Kurian,J.,2001, An integrated approach for management of total dissolved solids in reactive dyeing effluents, Proceedings Int. Conf. on Industrial Pollution and Control Technologies, Hyderabad. 8. Nageswara Rao,K., Narendra,K. and Venkateswarlu,P.,2007,; Assessment of groundwater quality in Mehadrigedda watershed, Visakhapatnam district, Andhra Pradesh, India: GIS approach, Pollution Research,26(3),pp Pradhan,S.K., Dipika,P. and Rout,S.P.,2001,: Water quality index for the groundwater in and around a phosphatic fertilizer plant, Indian Jour. Environ. Prot,21,pp Raghunath,H.M., Groundwater, New Age International (P) Ltd., New Delhi,2003, pp Sinha,D.K. and Saxena,R.,2006,: Statistical assessment of underground drinking water contamination and effect of monsoon at Hasanpur, J.P.Nagar (Uttar Pradesh, India), Jour. Environ. Sci. Engg,48(3),pp Subba Rao,C., Subba Rao,N.V., Priyadarsini,J.P. and Anila,V.N.,1997,:. Assessment of groundwater quality in the urban aquifers of Visakhapatnam, Jour. Applied Hydrology,X(3&4),pp Swarna Latha,P.,2008,: Studies on spatial and temporal changes of land use and land cover, groundwater quality and shoreline of Greater Visakhapatnam municipal corporation, Andhra Pradesh, India using remote sensing and GIS techniques. Unpublished Ph.D. Thesis Andhra University, Visakhatapatnam. 14. Swarna Latha,P. and Nageswara Rao,K.,2007,: Hydrochemical studies in an industrial area of Visakhapatnam city, India a spatial technology approach, Asian Jour. Microbiol. Biotech. Environ. Sci, 9(3),pp

15 15. Swarna Latha,P. Nageswara Rao,K. Ramesh Kumar,P.V. and Hari Krishna,M.,2007,: Water quality assessment at village level a case study, Indian Jour. Environ. Prot,27(11),pp Todd,D.K., Groundwater Hydrology, John Willey & Sons, New York,2001,pp Tiwari,T.N. and Mishra,M.A.,1985,: A preliminary assignment of water quality index on major Indian rivers,indian Jour. Environ. Prot,5,pp VUDA., Master plan for Visakhapatnam metropolitan region perspective 2021, Draft Plan, Visakhapatnam Urban Development Authority,2003, pp