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P. MADHUSUDHANA REDDY
Dept. of Geology, Dr. B.R. Ambedkar Open University, Hyderabad, India
N. SUBBA RAO
Dept. of Geology, Andhra University, Visakhapatnam, India
ABSTRACT
Hydrogeoenvironmental studies have been carried out in Gopalapatnam and Mindi which are polluted locations in the Visakhapatnam area, India. Water samples were collected from dug wells and analyzed for water quality studies. The concentrations of TDS, TH, Ca, Mg, Cl, SO4, Fe, Mn, Cu, Pb, and Cd in the waters of both locations were above the Indian Standards Institution recommended guidelines for drinking purposes. Pollution is attributed mainly to the influence of industrial effluents. Several health problems were observed in these locations. Environmental protection programs are needed to eliminate health hazards.
INTRODUCTION
Development of industrial activity causes deterioration of groundwater quality because of disposal of industrial effluents without pre-treatment on the ground. The present study area, the Viskhapatnam region located on the East Coast of India is no exception as it is one of the rapidly growing industrial areas in the state of Andhra Pradesh. Groundwater is the dominant source for public supply in this area. The aim of the present study is to investigate the state of groundwater quality of the wells used for drinking purpose in the area.
MATERIALS AND METHODS
A total of 11 dug wells (6 from Mindi and 5 from Gopalapatnam) were sampled from the study area (Figure 1). The samples were collected in the month of May 1992 in 500 ml plastic containers for chemical analysis. Standard methods were used for the determination of the chemistry of the waters (Brown et al. 1974). The parameters analyzed were pH, TDS, TA, TH, Ca, Mg, Na, K, HCO3, Cl, SO4, NO3, Fe, Mn, Cu, Pb, Zn, Cr, and Cd. All the above chemical constituents are expressed in mg/l (milligrams/liter) except pH.
GROUNDWATER CONDITIONS
The area under study forms a part of the Eastern Ghats tectonic complex. The prominent geological formations are composed mostly of a Khondalite suite of rocks. Generally they lack primary porosity and hydraulic conductivity. Secondary porosity develops due to weathering and deformation. The soil covering the weathered, semi-weathered, and semi-fractured and fractured zones in the area ranges from 1 to 8m, 1 to 18m, 1 to 55m, and 14 to 16m, with average thicknesses of 1.90, 10.6, 20.49 and 34.68m respectively (Subba Rao, 1992).
Groundwater occurs under water table conditions in the weathered zone at shallow depths as well as under semi-confined to confined conditions in fractured zones at deeper levels. Depth of the dug wells range from 3.8 to 8.6m bgl (below ground level) with the diameter varying from 1 to 4m. The water table is between 1.2 and 6m bgl. Generally the direction of movement of groundwater follows the topography of the area. Therefore, groundwater flow is towards the marsh land from the surrounding high lands in the area (Figure 1).
RESULTS
The results of the present study are shown in Table 1; which provides a comprehensive picture of the characteristics of the well waters in the area with respect to the various chemical indicators determined.
Table 1. Chemical Quality of Wells Representing Mindi and Gopalapatnam Industrial Areas (mg/l)
| Sample Numbers | |||||||||||||
| MINDI | GOPALAPATNAM | ||||||||||||
| Parameter | 1 | 2 | 3 | 4 | 5 | 6 | Average | 7 | 8 | 9 | 10 | 11 | Average |
| pH | 6.6 | 6.5 | 6.2 | 6.1 | 6.2 | 6.1 | 6.28 | 6.4 | 6.2 | 6.5 | 7.3 | 6.2 | 6.52 |
| TDS | 2848 | 2608 | 2896 | 2560 | 2240 | 2496 | 2608 | 2944 | 3008 | 2944 | 2496 | 2688 | 2816 |
| TH | 770 | 755 | 685 | 610 | 580 | 485 | 648 | 770 | 775 | 765 | 655 | 675 | 728 |
| TA | 106 | 123 | 254 | 148 | 172 | 213 | 169 | 467 | 364 | 295 | 352 | 360 | 368 |
| Ca | 145 | 120 | 130 | 115 | 100 | 80 | 115 | 60 | 55 | 60 | 80 | 55 | 62 |
| Mg | 99.3 | 110.8 | 87.7 | 78.6 | 80.4 | 69.4 | 87.7 | 150.8 | 155.1 | 149.6 | 110.8 | 130.8 | 139.4 |
| Na | 523 | 469 | 643 | 550 | 470 | 583 | 540 | 533 | 583 | 563 | 515 | 567 | 552 |
| K | 152 | 136 | 60 | 70 | 90 | 76 | 97 | 162 | 152 | 148 | 86 | 142 | 138 |
| HCO3 | 130 | 150 | 310 | 180 | 210 | 260 | 207 | 570 | 450 | 360 | 430 | 440 | 450 |
| Cl | 900 | 800 | 660 | 605 | 570 | 655 | 698 | 925 | 1035 | 975 | 925 | 215 | 815 |
| SO4 | 621 | 668 | 865 | 817 | 637 | 673 | 714 | 367 | 383 | 423 | 317 | 401 | 378 |
| Fe | 1.818 | 1.72 | 0.938 | 1.592 | 1.668 | N.A. | 1.547 | 0.906 | 0.928 | N.A. | 0.618 | 0.596 | 0.762 |
| Mn | 0.456 | 0.318 | 0.456 | 0.396 | 0.528 | N.A. | 0.43 | 0.292 | 0.468 | N.A. | 0.412 | 0.392 | 0.391 |
| Cu | 0.148 | 0.096 | 0.128 | 0.116 | 0.112 | N.A. | 0.12 | 0.126 | 0.129 | N.A. | 0.11 | 0.104 | 0.117 |
| Pb | 0.055 | 0.055 | 0.19 | 0.18 | 0.18 | N.A. | 0.132 | N.D. | N.D. | N.A. | N.D. | N.D. | N.A. |
| Zn | 0.065 | 0.064 | 0.58 | 0.52 | 0.52 | N.A. | 0.349 | 0.024 | 0.028 | N.A. | 0.019 | 0.012 | 0.02 |
| Cr | 0.092 | 0.08 | 0.098 | 0.092 | 0.094 | N.A. | 0.912 | 0.042 | 0.038 | N.A. | 0.039 | 0.042 | 0.0402 |
| Cd | 0.07 | 0.15 | 0.72 | 0.49 | 0.3 | N.A. | 0.346 | N.D. | N.D. | N.A. | N.D. | N.D. | N.A. |
| N.D: Not detected by instrument N.A: Not analyzed | |||||||||||||
The pH values ranged from 6.1 to 7.3 with an average value of 6.4 and did not show significant variation between Mindi and Gopalapatnam. Waters showed TDS values in the range of 2240 to 3008 mg/l in both locations. But the lowest and highest average values were noticed in Mindi and Gopalapatnam respectively. Similarly TH and TA values in the water samples were recorded in Mindi and Gopalapatnam. Among alkaline earth elements the Ca values ranged from 80 to 145 mg/l with an average of 115 mg/l at Mindi and from 55 to 80 mg/l with an average of 62 mg/l at Gopalapatnam. The values if Mg in well waters varied significantly between Mindi and Gopalapatnam and was found at higher levels at Gopalapatnam. The alkalis (Na+K) values were observed at higher levels at Gopalapatnam when compared to Mindi. Similarly the levels of HCO3 and Cl in well waters were recorded. The SO4 concentration was observed to be higher at Mindi compared with the values of it at Gopalapatnam. Similarly the lowest levels of Fe, Mn, Cu, Pb, Zn, Cr and Cd were recorded at Gopalapatnam and the highest values of these elements were found at Mindi.
DISCUSSION
Hydrochemical facies are characterized by Na-Cl type at Gopalapatnam and Na-Cl-SO4 type at Mindi. Groundwater at both the locations belong to brackish water type as per the TDS classification (Twart at al 1974). According to TH classification scheme (Sawyer and McCarthy 1967) they come under very hard category. The relation of TA with TH suggests that the waters have permanent hardness (non-carbonate hardness) because of predominance of sulfide and chloride contents.
Further, there are significant differences in the values of Fe, Mn, Cu, Pb, Zn, Cr and Cd between Mindi and Gopalapatnam well waters. These elements have higher values at Mindi than that of Gopalapatnam.
The results of this study indicate considerable deterioration in the groundwater quality of well waters in the study area is possibly due to the influence of Hindustan Polymers in Gopalapatnam and the Zinc smelter-Alum factory in Mindi, as the industrial effluents move in the direction of groundwater movement and flow towards marsh land through residential areas due to topographic control. Thus the enrichment of chemical constituents follows the chemistry of industrial effluents (Table 2).
Table 2. Chemical Composition of Industrial Effluents
|
Chemical Parameters |
Hindustan Polymers |
Zinc Smelter |
Alumfactory |
| pH | 5.7 | 2.5 | 1.9 |
| TDS | 6570 | 2820 | 2950 |
| Ca | 140 | 140 | 90 |
| Mg | 253 | 210 | 110 |
| Na | 1200 | 400 | 350 |
| K | 140 | 75 | 60 |
| Cl | 2000 | 375 | 400 |
| SO4 | 980 | 720 | 850 |
| TH | 1390 | 1213 | 677 |
| Fe | N.A. | 3.63 | 2.87 |
| Mn | N.A. | 1.96 | 2.00 |
| Cu | N.A. | 1.42 | 0.47 |
| Zn | N.A. | 1.34 | 1.15 |
| Cr | N.A. | 0.18 | 2.85 |
| Cd | N.A. | 2.14 | N.D. |
| Pb | N.A. | 0.82 | N.D. |
| N.A: Not Analyzed N.D: Not Detected | |||
| Source: Subba Rao and Krishna Rao (1988 and 1990) | |||
The pH values of groundwater from the study area are at the limit of the I.S.I. (Indian Standards Institution) 1983 guidelines of 6.5 to 8.5 for drinking purpose. Compared with I.S.I. for salinity of drinking waters, the wells have salinity (TDS) values above the I.S.I. standard of 1500 mg/l as presented in Table 1. Similarly the well waters have TH, Ca, Mg, Cl, SO4, Fe, Mn, Cu, Pb and Cd values more than I.S.I. desirable limits of 300, 75, 30, 250, 150, 0.3, 0.1, 0.05, 0.1, and 0.01 mg/l respectively for drinking purposes. As these concentration levels are higher than desirable limits, their effect on the human body is inevitable.
The incidence of important health hazards at both the locations are skin, alimentary, respiratory, nervous and a spinal card disorders, coronary heart disease, miscarriage and cancer, based on the personal observation of the authors and reports of the well owners. According to the information of long-standing residents of these locations these health problems have started only after the establishment of the industries.
CONCLUSION
In the groundwater of the study area total dissolved solids (TDS), TH, TA, Ca, Mg, Cl, SO4, Fe, Mn, Cu, Pb, and Cd have been found in excess of the I.S.I. recommended guideline values due to the impact of industrial effluents. These high values can be deleterious to the health of human beings and thus corrective measures are necessary to prevent increases of chemical parameters in groundwater and to safeguard public health.
AKNOWLEDGEMENTS
The first author is thankful to Prof. B.R.G. Reddy, Dept. of Geology, Andhra University, Visakhpatnam, A.P. India.
REFERENCES
Brown, E., Skougstad, N.W. and Fishman, M.J. Methods for collection and analysis of water samples for dissolved minerals and gases, U.S. Dept of Interior, Book-5, 160p,1974.
I.S.I. (Indian Standards Institution), Indian standard specification for drinking water, 15, 10500; 1983.
Sawyer, C.N., and McCarthy, B.L. Chemistry for sanitary Engineers, 2nd Ed. McGraw Hill Book Co., New York, 518p; 1967.
Subba Rao, N. Factors affecting optimum development of groundwaters in crystalline terrain of the Eastern Ghats Visakhapatnam area, Andhra Pradesh, India. Jour. Geol. Soc. India, Vol. 40, No. 5, pp. 462-467; 1992.
Subba Rao N., and Krishna Rao G., Trace elements in drinking water of Visakhapatnam area, Andra Pradesh, Geo. Phy. Res. Bull., Vol. 26, No. 4, pp. 140-144; 1988.
Subba Rao N. and Krishna Rao G., Intensity of Pollution of groundwater in Visakhpatnam area, Andhra Pradesh, India; 1990.
Twart, A.C., Hoather,R.C. and Law, F.M., Water Supply, Edward Arnold Ltd., London; 1974.,
P. Madhusudhana Reddy
Dept. of Geology
Dr. B.R. Ambedkar Open University
Hyderabad
INDIA 500 003