Statistical Analysis of Drinking Water Quality and its Impact on Human Health in Chandragiri, near Tirupati, India
By Narasimha Rao C.¹, Dorairaju S. V.², Bujagendra Raju M¹ and Chalapathi P. V.² *
December 2011
- Department of Chemical Engineering, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
- Department of Chemistry, S. V. Arts Degree and P. G. College, Tirupati, Andhra Pradesh, India * Corresponding Author
Abstract
Drinking water samples were collected from different locations of Chandragiri, near Tirupati, Andhra Pradesh, India and analyzed to assess physicochemical parameters and suitability of water for drinking purpose. Physicochemical parameters such as pH, hardness, alkalinity, calcium, magnesium, iron, nitrates, chlorides, sulphates, electrical conductivity, total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), dissolved oxygen (DO), chemical oxygen demand (COD) and bio chemical oxygen demand (BOD) were determined. The found values were compared with the World Health Organisation water quality standards. Interpretation of data through correlation studies shows that drinking water of some of the areas was polluted and not suitable for drinking purpose. Thus the ground water of these areas needs purification before drinking.
Keywords: Ground Water, Physicochemical Parameters, Alkalinity, Electrical Conductivity, Dissolved Oxygen, Bio Chemical Oxygen Demand
Introduction
Drinking water is one of the most important constituents for healthy living of human society. In India most of the people living in rural areas, depend on ground water for drinking purpose. Ground water is ultimate and most suitable fresh water resource. The quality of water may be described according to its physico-chemical and micro-biological characteristics
1. The particulate problem in case of water quality monitoring is the complexity associated with analysis of the large number of measured variables
2. In recent years an easier and simpler approach based on statistical correlation, has been developed using mathematical relationship for comparison of physicochemical parameters
3-6. The physico-chemical analysis of water samples was carried by many researchers using by standard methods
7-14.
Tirupati is located in the Chittoor district, Andhra Pradesh state, India. Chittoor district lies extreme south of Andhra Pradesh approximately between 12° 37’ – 14° 8’ north latitudes and 78° 3’ – 79° 55’ east longitudes. Most of the people in rural areas of Tirupati depend upon ground water for drinking and other domestic needs. Many pharma, plastic, cement, battery, beverage etc., industries were established in this area. The objective of the present work is to assess the drinking water quality parameters in this area and to study their effect on human health.
Experimental
The study was carried out during the period from June 2010 to June 2011 at Chandragiri area near Tirupati. The drinking water samples were collected in clean and dry polythene bottles. Each sample was filtered using whatmann no.42 filter paper and stored. The water samples collected were analyzed within 5 hours after collection. The temperature of the samples was measured in the field itself at the time of collection. The collected samples were kept in the refrigerator maintained at 4°C and analyzed for a few important parameters in order to have an idea on the quality of drinking water. The average results were presented in table 1 and 2.
Electrical conductivity values were measured using Elico CM 180 conductivity ridge. Total alkalinity was evaluated by titration with standard 0.1M HCl using methyl orange and phenolphthalein as indicators
15. Standard procedures
16 involving spectrophotometry, flame photometry and volumetry were used for the determination of hardness, total dissolved solids (TDS), sulphate, chloride, nitrate, calcium, magnesium iron etc., All the chemicals used were of AR grade.
Results and discussion
pH
The limit of pH value for drinking water is specified
17 as 6.5 to 8.5. PH value in the studied area varied between 6.4-8.4. All the sampling points showed pH values within the prescribed limit by WHO. Abnormal values of pH causes bitter taste to water, affects mucous membrane, causes corrosion and also affests aquatic life.
Hardness
The total hardness is relatively high in all samples due to the presence of calcium, magnesium, chloride and sulphate ions. High amount of hardness in drinking water leads to heart diseases and kidney stone formation
18. Hardness value in the studied area varied between 412-534 mg/L. 6 sampling points showed higher hardness values than the prescribed limit by WHO. Exceeding the permissible limit of hardness causes poor lathering with soap, deterioration of the quality of clothes, scale formation and skin irritation.
Alkalinity
Water with high amount of alkalinity results in unpleasant taste to water and it turns boiled rice to yellowish colour. Various ionic species that contribute to the alkalinity include hydroxide, carbonates, bicarbonates and organic acids. These factors are characteristic sources of water and many natural processes take place at any place
19. Alkalinity value in the studied domestic area varied between 195-561 mg/L. 30 sampling points showed higher alkalinity values than the prescribed limit by WHO.
Calcium
Calcium value in the studied area varied between 56-3014 mg/L. 30 sampling points showed higher calcium values than the limit prescribed by WHO If calcium is present beyond the maximum acceptable limit, it causes incrustation of pipes, poor lathering and deterioration of the quality of clothes.
Magnesium
Magnesium value in the studied area varied between 50-83 mg/L. 39 sampling points showed higher magnesium values than the limit prescribed by WHO. Too high magnesium will adversely affect crop yields as the soils become more alkaline.
Iron
Iron value in the studied area varied between 0.18-0.73 mg/L. 35 sampling points showed higher iron values than the prescribed limit by WHO. The excess amount of iron causes slight toxicity, gives stringent taste to water and can cause staining laundry and porcelain.
Nitrates
Groundwater contains nitrate due to leaching of nitrate with the percolating water and by sewage and other wastes rich in nitrates. Nitrate value in the studied area varied between 3.2-28.4 mg/L. All sampling points showed nitrate values within the prescribed limit by WHO. In the present study, the sampling points in which nitrate has been found to be high, can result in formation of nitroso-amines which are carcinogenic.
Chlorides
Soil porosity and permeability also has a key role in building up the chlorides concentration
20. Excessive chloride concentration increase rates of corrosion of metals in the distribution system. This can lead to increased concentration of metals in the supply
21. Chloride value in the studied area varied between 215-330 mg/L. 27 sampling points showed higher chloride values than the prescribed limit by WHO. The higher values of chloride can cause corrosion and pitting of iron pipes and lates.
Sulphates
Sulphate occurs naturally in water as a result of leaching from gypsum and other common minerals. Sulphate content in drinking water exceeding the 400 mg/L impart bitter taste and may cause gastro-intestine irritation and cantharsis
22. Sulphate value in the studied area varied between 145-233 mg/L. 15 sampling points showed higher sulphate values than the prescribed limit by WHO. Ingestion of water with high sulphates cause laxative effect and gastro-intestinal irritation.
Dissolved Oxygen (DO)
DO value in the studied area varied between 2.3-5.9 mg/L. 11 sampling points showed higher DO values higher than the prescribed limit by WHO. High amount of DO imparts good taste to water.
COD
COD in the studied area varied between 8.2-45 mg/L. Water with high COD indicates that there is inadequate oxygen available in the water samples.
BOD
BOD value in the studied area varied between 1.6-3.5 mg/L. All sampling points showed BOD values within the prescribed limit by WHO. Ground water with high value of BOD is due to microbial activities related to the dumpsites.
Conductivity
Electrical conductivity (EC) of water is a direct function of its total dissolved salts
23. Hence it is an index to represent the total concentration of soluble salts in water
24. Conductivity value in the studied area varied between 992-2492 µS/cm. 14 sampling points showed higher conductivity than the prescribed limit by WHO. If drinking water has high conductivity, it indicates the presence of high amount of dissolved inorganic substances in ionized form.
Solids
High values of TDS in ground water are generally not harmful to human beings but high concentration of these may affect persons who are suffering from kidney and heart diseases
25,26. A high content of dissolved solids elevates the density of water, influences osmoregulation of fresh water organism, reduces solubility of gases (like oxygen) and reduces utility of water for drinking, irrigation and industrial purposes
27. TS, TDS and TSS values in the studied area varied between 331-1192 mg/L, 308-1138 mg/L and 22-152 mg/L respectively. 31 sampling points showed higher TDS values than the prescribed limit by WHO. Continuous comsuption of water with high TDS content can cause gastro-intestinal irritation. It also causes undesirable taste and corrosion or incrustation.
Correlation Studies
Interrelationship studies between different water quality parameters are very helpful in understanding geochemistry of the studied area. The regression equations for the parameters having significant correlation coefficients are useful to estimate the concentration of other constituents. Correlation co efficient values samples are presented in table 3. Alkalinity shows significant correlation with calcium indicating that the alkaline nature of ground water is mainly due to calcium salts. Calcium shows good correlation with chlorides indicating that calcium is associated with chlorides in water of the studied area. Conductivity shows significant correlation with calcium, chlorides and DO which reveals that conductance of water samples is mainly due to calcium and chlorides in the ground water of the studied area.
Conclusions
Over exploitation of resources and improper waste disposal practices affected the drinking water quality. According to WHO, nearly 80% of all the diseases in human beings are caused by water
28,29. Based on the results obtained for physicochemical analysis of ground water samples collected from different locations in the studied Chandragiri area, near Tirupati, it can be concluded that in some samples water quality parameters were beyond the permissible limit prescribed by WHO. Hence, drinking water in the studied area requires precautionary measures before drinking so as to protect human beings from adverse health effects.
Table 1 · Average Results of Chemical Parameters of Ground Water of Athuru, an industrial area near TirupatiSampling Point | pH | Hardness (mg/L) | Alkalinity (mg/L) | Ca2+ (mg/L) | Mg2+ (mg/L) | Fe2+ (mg/L) | NO3- (mg/L) | Cl- (mg/L) | SO42- (mg/L) |
S 1 | 6.6 | 420 | 214 | 73 | 53 | 0.44 | 8.2 | 247 | 177 |
S 2 | 6.8 | 428 | 285 | 107 | 57 | 0.64 | 13.5 | 252 | 170 |
S 3 | 7.8 | 436 | 403 | 155 | 58 | 0.41 | 13.1 | 263 | 152 |
S 4 | 7.6 | 472 | 499 | 145 | 59 | 0.53 | 11.6 | 260 | 233 |
S 5 | 6.8 | 534 | 368 | 118 | 62 | 0.59 | 16.4 | 254 | 151 |
S 6 | 8.3 | 490 | 500 | 300 | 65 | 0.25 | 15.6 | 291 | 191 |
S 7 | 8.1 | 412 | 387 | 178 | 76 | 0.44 | 4.6 | 271 | 163 |
S 8 | 7.7 | 516 | 505 | 150 | 80 | 0.45 | 25.9 | 262 | 183 |
S 9 | 8 | 505 | 524 | 173 | 59 | 0.39 | 14.2 | 269 | 146 |
S 10 | 6.4 | 430 | 226 | 61 | 51 | 0.5 | 7.1 | 231 | 180 |
S 11 | 6.5 | 429 | 215 | 68 | 50 | 0.5 | 19.4 | 240 | 171 |
S 12 | 6.4 | 428 | 216 | 59 | 57 | 0.63 | 16.3 | 230 | 219 |
S 13 | 6.6 | 442 | 397 | 99 | 60 | 0.73 | 18 | 251 | 155 |
S 14 | 6.7 | 443 | 348 | 105 | 66 | 0.54 | 5.4 | 252 | 166 |
S 15 | 6.4 | 431 | 195 | 64 | 50 | 0.47 | 14 | 235 | 199 |
S 16 | 6.5 | 419 | 212 | 65 | 57 | 0.52 | 17.3 | 238 | 217 |
S 17 | 8.1 | 461 | 418 | 185 | 64 | 0.33 | 3.9 | 279 | 196 |
S 18 | 7.8 | 513 | 471 | 158 | 66 | 0.29 | 19.5 | 263 | 187 |
S 19 | 7.9 | 527 | 512 | 160 | 69 | 0.47 | 4.6 | 266 | 163 |
S 20 | 8.2 | 506 | 491 | 254 | 67 | 0.38 | 15.5 | 285 | 189 |
S 21 | 8.3 | 456 | 298 | 275 | 73 | 0.46 | 28.4 | 289 | 184 |
S 22 | 8.3 | 483 | 501 | 287 | 68 | 0.34 | 3.4 | 289 | 184 |
S 23 | 8.1 | 488 | 561 | 189 | 71 | 0.31 | 27.2 | 282 | 171 |
S 24 | 8.2 | 451 | 359 | 200 | 77 | 0.27 | 15.6 | 283 | 145 |
S 25 | 6.9 | 442 | 352 | 118 | 63 | 0.53 | 15.1 | 257 | 168 |
S 26 | 6.5 | 434 | 225 | 70 | 54 | 0.43 | 16.3 | 241 | 172 |
S 27 | 6.8 | 446 | 310 | 108 | 68 | 0.51 | 15.4 | 252 | 180 |
S 28 | 6.5 | 437 | 219 | 72 | 57 | 0.36 | 4.6 | 243 | 198 |
S 29 | 7.3 | 460 | 279 | 143 | 60 | 0.45 | 3.4 | 260 | 191 |
S 30 | 6.9 | 451 | 482 | 125 | 65 | 0.34 | 3.8 | 259 | 172 |
S 31 | 7 | 434 | 410 | 125 | 70 | 0.59 | 16 | 259 | 180 |
S 32 | 7.1 | 453 | 413 | 140 | 70 | 0.23 | 7.5 | 260 | 181 |
S 33 | 8.4 | 472 | 541 | 301 | 79 | 0.33 | 11.4 | 330 | 223 |
S 34 | 8 | 431 | 373 | 170 | 68 | 0.4 | 27.5 | 266 | 178 |
S 35 | 6.6 | 430 | 444 | 87 | 64 | 0.18 | 9.5 | 247 | 180 |
S 36 | 6.4 | 412 | 277 | 56 | 56 | 0.4 | 3.2 | 215 | 192 |
S 37 | 6.6 | 434 | 210 | 88 | 58 | 0.5 | 7.7 | 250 | 171 |
S 38 | 8.1 | 416 | 378 | 178 | 83 | 0.42 | 13.4 | 273 | 178 |
S 39 | 6.4 | 434 | 199 | 62 | 58 | 0.52 | 25.4 | 234 | 218 |
S 40 | 6.5 | 469 | 296 | 185 | 63 | 0.37 | 16.8 | 221 | 194 |
WHO | 6.5-8.5 | 500 | 250 | 75 | 50 | 0.3 | 45 | 250 | 200 |
Table 2 · Average Results of Physical and Biological Parameters of Ground Water of Athuru, an industrial area near TirupatiSampling Point | Physical Parameters | Biological Parameters |
Temp (°C) | Conductivity (µS/cm) | Total Solids (TS) (mg/L) | Total Dissolved Solids (TDS) (mg/L) | Total Suspended Solids (TSS) (mg/L) | Dissolved Oxygen (DO) (mg/L) | Chemical Oxygen Demand (COD) (mg/L) | Biochemical Oxygen Demand(BOD) (mg/L) |
S 1 | 31 | 1333 | 422 | 394 | 28 | 5.3 | 14.1 | 2 |
S 2 | 31.2 | 1418 | 431 | 393 | 38 | 4.5 | 8.2 | 2.1 |
S 3 | 30.6 | 1624 | 884 | 830 | 54 | 4 | 28 | 2.9 |
S 4 | 32 | 1520 | 888 | 847 | 41 | 4.1 | 27.9 | 2.4 |
S 5 | 31.8 | 1434 | 924 | 891 | 33 | 4.5 | 25.2 | 2.2 |
S 6 | 31.5 | 2292 | 1051 | 984 | 67 | 2.5 | 10.2 | 3.4 |
S 7 | 31.6 | 1924 | 489 | 443 | 46 | 3.4 | 9.9 | 3 |
S 8 | 31 | 1616 | 528 | 452 | 76 | 4 | 17.7 | 2.9 |
S 9 | 31.5 | 1896 | 582 | 524 | 58 | 3.4 | 12.3 | 3 |
S 10 | 31.4 | 1254 | 1148 | 1107 | 41 | 5.7 | 34 | 1.7 |
S 11 | 31.8 | 1288 | 1045 | 1002 | 43 | 5.5 | 33.5 | 2 |
S 12 | 32 | 1186 | 971 | 931 | 40 | 5.8 | 34.7 | 1.6 |
S 13 | 31.9 | 1356 | 880 | 832 | 48 | 4.8 | 12.9 | 2.1 |
S 14 | 30.7 | 1408 | 1063 | 1013 | 50 | 4.6 | 19.5 | 2.1 |
S 15 | 30.7 | 1259 | 891 | 846 | 45 | 5.6 | 42.1 | 1.8 |
S 16 | 31.5 | 1281 | 1073 | 1002 | 71 | 5.5 | 24.5 | 1.9 |
S 17 | 31.8 | 1984 | 1060 | 1003 | 57 | 3.3 | 27.8 | 3.1 |
S 18 | 31.6 | 1816 | 507 | 414 | 93 | 3.6 | 18 | 2.9 |
S 19 | 31.8 | 1836 | 426 | 377 | 49 | 3.5 | 10.3 | 3 |
S 20 | 31.5 | 2038 | 923 | 857 | 66 | 3 | 15.3 | 3.3 |
S 21 | 31 | 2075 | 959 | 893 | 66 | 3 | 12.9 | 3.3 |
S 22 | 30.9 | 2137 | 1190 | 1104 | 86 | 2.8 | 11.8 | 3.3 |
S 23 | 30.9 | 2012 | 775 | 697 | 78 | 3.3 | 16 | 3.2 |
S 24 | 31.2 | 2034 | 875 | 816 | 59 | 3.3 | 13.2 | 3.2 |
S 25 | 30.7 | 1440 | 852 | 806 | 46 | 4.4 | 14.8 | 2.3 |
S 26 | 32.3 | 1310 | 1192 | 1138 | 54 | 5.5 | 44.4 | 2 |
S 27 | 32.3 | 1429 | 774 | 731 | 43 | 4.5 | 22 | 2.2 |
S 28 | 30.8 | 1326 | 820 | 767 | 53 | 5.4 | 43 | 2 |
S 29 | 31.7 | 1515 | 412 | 341 | 71 | 4.1 | 14.4 | 2.4 |
S 30 | 30.9 | 1444 | 877 | 839 | 38 | 4.4 | 28 | 2.3 |
S 31 | 32.1 | 1454 | 331 | 308 | 23 | 4.3 | 20.8 | 2.4 |
S 32 | 31.3 | 1460 | 999 | 944 | 55 | 4.2 | 13.9 | 2.4 |
S 33 | 31.2 | 2492 | 744 | 710 | 34 | 2.3 | 12.9 | 3.5 |
S 34 | 31.4 | 1876 | 869 | 794 | 75 | 3.5 | 14.1 | 3 |
S 35 | 32 | 1340 | 978 | 902 | 76 | 5.3 | 45 | 2 |
S 36 | 32.7 | 992 | 504 | 482 | 22 | 5.9 | 44 | 1.6 |
S 37 | 32 | 1356 | 748 | 717 | 31 | 5 | 23.2 | 2.1 |
S 38 | 31.4 | 1970 | 955 | 902 | 53 | 3.4 | 18 | 3 |
S 39 | 32.8 | 1255 | 644 | 597 | 47 | 5.6 | 36.8 | 1.8 |
S 40 | 32.1 | 1528 | 849 | 697 | 152 | 4 | 17.2 | 2.8 |
WHO | 30.0 | 1800 | | 500 | | 5.0 | | 6.0 |
Table 3 · Correlation Coefficient Values of various Physico-Chemical Parameters of Ground Water of Athuru, an industrial area near Tirupati | pH | TH | TA | Ca2+ | Mg2+ | Fe2+ | NO3- | Cl- | SO42- | DO | COD | BOD | Temp | Cond | TS | TDS | TSS |
pH | 1 | | | | | | | | | | | | | | | | |
TH | 0.4835 | 1 | | | | | | | | | | | | | | | |
TA | 0.73317 | 0.66123 | 1 | | | | | | | | | | | | | | |
Ca2+ | 0.8884 | 0.50873 | 0.67989 | 1 | | | | | | | | | | | | | |
Mg2+ | 0.70262 | 0.30377 | 0.61372 | 0.65857 | 1 | | | | | | | | | | | | |
Fe2+ | -0.4485 | -0.208 | -0.4151 | -0.4558 | -0.3306 | 1 | | | | | | | | | | | |
NO3- | 0.124 | 0.15951 | 0.0126 | 0.11112 | 0.1595 | 0.1555 | 1 | | | | | | | | | | |
Cl- | 0.88574 | 0.43211 | 0.69877 | 0.87233 | 0.68541 | -0.3847 | 0.06996 | 1 | | | | | | | | | |
SO42- | -0.1172 | -0.1217 | -0.1525 | -0.0087 | -0.1154 | -0.0152 | 0.03311 | -0.07 | 1 | | | | | | | | |
DO | -0.9396 | -0.5517 | -0.7625 | -0.9541 | -0.7325 | 0.41862 | -0.101 | -0.8944 | 0.13603 | 1 | | | | | | | |
COD | -0.6204 | -0.3817 | -0.483 | -0.6465 | -0.5579 | 0.00179 | -0.1167 | -0.6138 | 0.30655 | 0.74159 | 1 | | | | | | |
BOD | 0.95116 | 0.54133 | 0.72896 | 0.93933 | 0.72054 | -0.4905 | 0.17637 | 0.86212 | -0.1561 | -0.9728 | -0.6678 | 1 | | | | | |
Temp | -0.3171 | -0.0883 | -0.2162 | -0.2902 | -0.1907 | 0.192 | 0.04497 | -0.3923 | 0.24676 | 0.30919 | 0.3186 | -0.3193 | 1 | | | | |
Cond | 0.94454 | 0.48011 | 0.68622 | 0.94543 | 0.69288 | -0.4762 | 0.13432 | 0.92656 | -0.066 | -0.9576 | -0.6381 | 0.96102 | -0.3178 | 1 | | | |
TS | -0.0423 | -0.102 | -0.0893 | 0.08909 | -0.127 | -0.1583 | 0.03496 | 0.02706 | 0.09417 | 0.04565 | 0.28822 | -0.0191 | -0.1529 | 0.04924 | 1 | | |
TDS | -0.0665 | -0.1357 | -0.1112 | 0.05288 | -0.1495 | -0.1185 | 0.00781 | 0.02247 | 0.08892 | 0.07986 | 0.31367 | -0.0607 | -0.1473 | 0.01995 | 0.99529 | 1 | |
TSS | 0.23966 | 0.32822 | 0.21044 | 0.37931 | 0.21082 | -0.4254 | 0.28 | 0.05029 | 0.06602 | -0.3406 | -0.2187 | 0.41857 | -0.0777 | 0.30372 | 0.18442 | 0.08827 | -0.0777 |
TH= Total Hardness, TA= Total Alkalinity, DO=Dissolved Oxyen, COD=Chemical Oxyen Demand, BOD=Biochemical Oxyen Demand, Temp=Temperature, Cond=Conductivity, TS=Total Solids, TDS=Total Dissolved Solids, TSS=Total Suspended Solids
All the parameters measured as mg/L except Temperature (°C) and Conductivity (µS/cm)
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