Multivariate analysis of Cauvery River water quality around KRS Dam, Karnataka, India

Transcription

1 Symposium of Lake 28 Multivariate analysis of Cauvery River water quality around KRS Dam, Karnataka, India S.SRIKANTASWAMY*, SIAMAK GHOLAMI DEPARTMENT OF ENVIRONMENTAL SCIENCE, UNIVERSITY OF MYSORE, MANASAGANGOTRI, MYSORE 57 6, KARNATAKA, INDIA *Corresponding Author- E amil: srikantas@hotmail.com

2 Introduction Rivers are essential for thesurvival of any forms of life. Some loads of waste from industries, domestic sewage and agricultural practices find their way into rivers, resulting in large scale deterioration of the water quality Increasing urbanization and industrialization has been deteriorating the water quality of the reservoir resources as discharge of sewage and municipal wastes into water bodies have negative impacts In the present study water quality analysis of Cauvery River around Krishna Raja Sagar (KRS) Dam has been carried out in order to determine the sources responsible for deterioration of water quality for various uses. More than 7 percent of the drinking water supply to Mysore city is from the Cauvery River, hence it is important to monitor the water quality of Cauvery River This river is also under environmental stress due to siltation, human encroachment, high macrophytic population and sewage in put from various sources There are number of discharging loads of sewage, domestic waste water and industrial effluents directly into the river

3 The River basin of Cauvery is one of the major rivers of India. Cauvery River originates at Talakavery in the Western Gates in the state of Karnataka, flows generally south and east through Karnataka, and there are many tributaries. Studies were carried out around the KRS dam and downstream. There are activities like irrigation, agricultural and industrial basin around the dam and river Location - Across River Cauvery near Kannambadi Village a)latitude 12 25' 3" N b)longitude 76 34' 3" E c)taluk Srirangapatna d)district Mandya Level of Storages. i) Full reservoir level (FRL) Feet ii) Minimum drawdown level (MDDL) 74. Feet iii) Dead storage level 6. Feet

4 This river flows through Karnataka and Tamil Nadu and across the south of Deccan plateau through the southeastern lowlands, emptying into the Bay of Bengal throughtwoprincipal p mouths. Figure2: Locations map of water quality monitoring Station around K.R.S. Dam

5 Sampling collection Stations BD 1 =Upstream of dam below the high way bridge of Hemavathi River BD 2 =Upstream of dam below the high way bridge of Cauvery River BD 3 =Upstream of dam below the high way bridge of Laxmanatheertha River. D 1 = Upstream of dam below the railway bridge (Sagarakatte rail Station). D 2 =Upstream of dam at a distance of 5 Kms from the gate of the dam. R 1 =At the gate of the dam. R 2 =At KRS garden (Brindavan). R 3 =Downstream of dam near bridge. R 4 =Downstream of River at Balamurikshetra. R 5 =Downstream of River at Ranganathittu Bird Sanctuary. R 6 =Downstream of River near first bridge at Srirangapathana Station. R 7 =Downstream of River under the second bridge at Srirangapathana Station. R 8 =Downstream of River at Sangam, at confluence of two tributaries of Cauvery river.

6 Materials and methods Water samples collection and analysis were carried out as per standard method of sampling techniques, APHA, (1992). Various physico-chemical parameters like temperature, ph, EC, alkalinity, total hardness, total dissolved solids (TDS), Ca +2, Mg +2, Na +, K +, chloride (Cl - ), sulfate (SO -2 4 ), nitrate (NO - 3 ), phosphate (PO -3 4 ), dissolved oxygen (DO) and COD were determined using standard methods. The temperature of the water was recorded using a thermoprobe on the spot. Electrical conductivity and ph were also recorded in the lab, DO was determined using Winkler s method on the site itself. Calcium and magnesium were estimated using EDTA Titrimetry, Sodium and potassium by flame photometry, chlorides by Argentometry, sulfate by Nephalometry, and phosphates by molybdenum-blue complex formation using a spectrophotometer. Nitrate was estimated by acid treatment followed by Spectrophotometry and estimation of COD was done by reflux Titrimetry. The quality assurance and quality procedure were also used as described in APHA. The data were statistically analyzed for t-test and inter correlations matrix using the SPSS 15 software package

7 Results and Discussion Ca +2, which is a major component of natural waters comes mainly from the rocks, seepage, wastewater etc. Ca +2 is varied from 8.8 to 38.5 mg/l in upstream, and in down stream remained low (26.47 mg /l) during winter, But Mg +2 varied from 2.5 to 36.1 mg/l in the study area. Fig 3(a-d) Ca +2, Mg +2 levels in the summer were more than in the winter, belongs to same sources. This indicated of precipitation of Mg +2 in downstream zones is due to vegetation, which is also shown by greater hardness of the downstream at R8 This can be correlated to SO 4-2, HCO 3 -, Cl -, which depends on mining sources. The concentration of Mg +2 was more in upstream but the concentration was lower (1 to 2 mg /L) in the downstream. II-Winter/27-8 III-Summer/28 II-Winter/27-8 III-Summer/ /l) Ca +2 (mg/ Mg +2 (mg g/l) Figure 3a, variations of Ca +2 Figure 3b, variations of Mg +2

8 At the Station of BD 3 the Na + concentration increased sharply to 2 mg/l in upstream and then decrease after mixing with Water in reservoir to 5 mg/l and then increasing in Cauvery downstream, after the influence of agricultural wastes p to 25 mg/l in station Sangam (R 8 ). The levels of Na + were elevated in the range of mg /L. Such high levels of Na + would be a potential pollution for the crops if the water were used for irrigation. The presence of K + in the natural waters is very important since it is an essential nutrient element for plant. The concentration ti of K +, was quite low in summer (2 to 14 mg /L) in the downstream due to influence of agricultural waste water, which increased up to 14mg/l in the lower segment, the concentrations were higher during winter (Fig.3d). Na + (mg/l) ll-winter/27-8 lll-summer/28 ) K + (mg/l II-Winter/27-8 III-Summer/28 Figure 3c, variations of Na + Figure 3d, variations of K +

9 HCO 3 - and excess of Cl - in river water is usually taken as an index of pollution Desirable recommended limit for chloride is 25 mg/l by ISI - The HCO 3 is compared with chloride ion, it is having less tolerance value due to mineral sources as shown in correlation matrix (table 4). Upstream p at Station BD is having HCO maximum up to mg/l (Fig.3e and table 2), but tended to remain within permissible limits. During the summer, the Cl - ion of Cauvery River was between ( mg /l). The concentration of Cl - in the river water was slightly higher in the summer sampling than in winter (Fig.3f),. II-Winter/27-8 III-Summer/28 II-Winter/27-8 III-Summer/28 HCO - 3 (mg/l) Cl - (mg/l) Figure 3e, variations of HCO - 3 figure 3f, variations of Cl - (28)

10 The SO 4-2 concentration in the river varied from.12 to 3.16 mg/l in Cauvery upstream and increased from.41 to 3.16 mg/l in Cauvery downstream. The concentration of SO 4-2 was much lower during Winter (Fig.3g). Winter-27-8 Summer-8 SO 4-2 (mg/l) Figure 3g, variations of SO 4

11 PO 4-3 may enter into surface water from human-generated wastes and natural run-off. The concentration of PO 4-3 was low in the river water, ranging from (.48 to.5mg/l) in Cauvery upstream. PO 4-3 is correlated to K + and is depended on pollutants in river water. This is due to agricultural runoff containing fertilizers as well as waste water containing detergents etc. which to increase PO 4-3 pollution in the downstream of water. ti -3 The concentration of PO 4 was much hlower during Summer( (Figure 3h) Due to high activity of alga in summer NO 3 - is more than PO 4-3 Common sources of nitrate contamination include fertilizers, animal wastes, septic tanks, municipal sewage treatment systems, and decaying plant debris. NO 3 - levels were quite low; varying from (.35 to.1 mg/l) during summer (Fig.3i) The Correlation matrix indicates that there are only EC and TDS correlated with nitrogen in the Cauvery River main stream and some tolerance II-Winter/27-8 III-Summer/28 II-Winter/27-8 III-Summer/28 PO 4-3 (mg/l) NO 3 - (mg/l) Figure 3h, variations of PO 4-3 (28) Figure 3i, variations of NO 3 - (28)

12 TDS is a measure of the solid materials dissolved in the river water. This includes salts, some organic materials, and a wide range of other material from nutrients to toxic materials. In the present study TDS ranged from minimum of 5 at station BD 1 and maximum of 32 in BD 3 in Laxmanatheertha River during summer( Figure 3j) EC is used as a basic index to select the suitability of water for agricultural purposes. In the present study EC was minimum of 137 μmhos/cm at BD 1 (Hemavathy) and maximum of 67.2 μs/cm of in BD 3 (Laxmantheerth). In Figure 3k, The variations of EC are indicated that values are under all standard water quality permissible EC, TDS II-Winter/27-8 and all in behind III-Summer/28 Dam duo to runoff II-Winter/27-8 is more than the 7 downstream TDS 9m g/l) BD1 BD2 BD3 D1 D2 R1 R2 R3 R4 R5 R6 R7 R8 Figure 3j, variations of TDS EC BD1 BD2 BD3 D1 D2 R1 R2 R3 R4 R5 R6 R7 R8 III-Summer/28 Figure 3k, variations of EC

13 Turbidity is a measure of the dispersion of light in a column of water. It is caused due to presence of suspended matter, clay silt, colloidal organic particles, plankton and other microscopic organisms. In the present study turbidity was minimum of 1(NTU) at BD 1, R 1, R 8 and maximum of 22 in Winter at the same station (R 8 ) (Figure 3l ) 8 25 II-Winter/27-8 III-Summer/28 ty (NTU) Turbidi Figure 3l, variations of Turbidity (28)

14 DO is one of the water quality index and like DO in Summer is less than in Winter Duo to Alga activity and high turbidity In this study, it varied from mg/l during summer and Winter The highest DO was 8.3 mg/l in the reservoir (D 1 ) in winter Variations of DO in summer is compare with Correlation matrix (Pearson) is + 3 dependent to Temperature and Turbidity, ph, TSS, TH, K +, Po 4-3 II-Winter/27-8 III-Summer/28 9 DO (mg/l) ( Figure 3p, variations of DO

15 Total Alkalinity in this study ranged from mg/l. Alkalinity was approximately constant in down stream and it is not more than15 mg/l (Figure 3n ) In the Summer AL< TH. Hence, Ca +2, Mg +2 are Also present in forms other than carbonate hardness In Winter AL>TH So, it means that all the hardness is presented as carbonate hardness In the present study, minimum of 32 mg/l and maximum of 24 mg/l of Total hardness is recorded at upstream BD 1 and BD 3 Stations respectively Average of Hardness was ( mg/l) in summer (Figure 3o) II-Winter/27-8 III-Summer/28 II-Winter/27-8 III-Summer/ kalinity (mg/l) /l) TH (mg/ Al Figure 3n, variations of Alkalinity (28) Figure 3o, variations of TH (28)

16 The BOD test provides an estimate of how much biodegradable waste is present in the water Here BOD varied from mg/l during winter and summer. Average of BOD in summer was highest, 2.52 mg/l during Summer than winter (Figure 3q). The COD is a measure of oxygen equivalent to the organic matter content of the water susceptible to oxidation by a strong chemical oxidant and thus is an index of organic pollution in the river The Highest COD level at station BD 3 was 45 mg /l in winter. Also it was more during summer in other. The Correlation matrix indicates that there are only Turbidity and K +,PO -3 4 and nitrogen correlated to COD in the Cauvery River (Figure 3r), which indicate that, there are discharges of non-point detergents influents in river. BOD (mg/l) ll-winter/27-8 lll-summer/28 COD (m mg/l) ll-winter/27-8 lll-summer/28 Figure 3q, variations of BOD Figure 3r, variations of COD

17 Inter-relationships Table 4, presents the correlation matrix between various parameters. Most of the parameters were found to bear statistically significant correlation with each other indicating close association of these parameters with each other. The ph and DO of the water, however, showed a highly positive correlation (r ~.92, df ~ 3, p <.1). Both the parameters are indicators of good quality water indicating the various favorable conditions for high h primary and secondary production. TDS and EC also had a strong correlation with a number of parameters + like Cl 2 (r ~.9137), hardness (r ~.9669), Mg (r ~.9634), Na + (r ~.9915), K + (r ~.9724), and SO 4-2 (r ~.8374).

18 Na + is well correlated with Cl - and SO 4-2. However, Ca +2 bears a significant ifi correlation with ithec, TDS, SO , PO 4 and other cations. This indicates the presence of calcium in the water in less soluble forms, more likely in the form of carbonates, which is also indicated by the high values of hardness in the river water. Dissolved oxygen showed significantly negative correlation with all the parameters except ph with which h it had a positive correlation. Only Ca +2 and Mg +2 did not show any significant correlation with DO. Thus DO can serve as a single useful index of water quality of the river because with increase in the value of most of these parameters, the DO decreases.

19 Table 2: Descriptive Statistics of water Quality (SPSS) for Cauvery River (3 sample in summer) Descriptive Statistics N. Parameter Maximum Minimum Mean Standard Deviation Std. Error Mean 1 Temperature Turbidity ubdty ph EC TS TSS TDS TH Ca Mg Na K Alkalinity HCO Cl S No Po DO BOD COD Fe

20 Table 4: Correlation matrix (Pearson) of water quality parameters for summer, 28 Tempe rature Turbidity ph EC TS TSS TDS TH Ca +2 Mg +2 Na + K + Alkalinity HCO3 Cl - S4-2 No3 - Po4-3 DO BOD COD Tempe rature 1 Turbid ity -.8* 1 ph EC TS * 1 TSS **.4 1 TDS * TH * Ca * * 1 Mg * *.64 1 Na K * Alkali nity * HCO * * 1 Cl * * S * No Po ** DO * -.54**.15*.31.66* -.3*.73*.64*.7* BOD * COD correlations significant at the.1 level (1- tailed) correlations significant at the.5 level (1- tailed)

21 Table 5: Physico-Chemical characteristics of the water samples collected at KRS Dam and all Upstream & Downstream of CAUVERY River (Winter-28) Winter Temperature Turbidity ph EC TS TS S TDS TH Ca +2 Mg +2 Na + K + Alkalinity HCO3 Cl - S4-2 No3 - Po4-3 DO BOD COD BD BD BD DR DR R R R R R R R R

22 Table 6: Physico-Chemical characteristics of the water samples collected at KRS Dam and all Upstream & Downstream of CAUVERY River (Summer -28) Summer Temperat Turbidi Alkalinili i HCO S4 - No3 Po4 - BO CO ure ty ph EC TS TSS TDS TH Ca +2 Mg +2 Na + K + ty 3 Cl DO D D BD BD BD DR DR R R R R R R R R

23 Conclusion The physico-chemical h i parameters studied d were all within the desirable limit it for drinking water quality recommended by WHO (1996) and BIS (1991). From this study, However, there is the need for routine checks to ascertain the suitability or otherwise of these water sources so as to forestall outbreak of water borne diseases. The above data on the water quality parameters of Cauvery River clearly showed that river water was safe for drinking water supply, fishery, irrigation, and industrial purposes, as most of the parameters are found within the permissible limits. During the monsoon season runoff could not change water quality in bad situation. Total Hardness was higher than Alkalinity (TH>TA) that is means its Non-alkalinity water and it is suitable to water pipe line. The present study has thus clearly revealed the extent of Phosphate, Nitrate in upstream and at reservoir during monsoon time and highest EC, Sulphate Total Hardness, TDS in Laxmantheerth ( BD 3 ) upstream Also the value of ph, EC, T. Alkalinity, TH, TDS, chloride was in lowest condition. But, Nitrate, Phosphate and Turbidity were more during other times. Finally, we compared the water quality index of three seasons. It provides a simple representation of extensive e and complex variables (physical, chemical) that govern the overall quality of surface water that is intended for potable use Compromise between water resources development and the maintenance of a river in ecologically acceptable or agreed condition is necessary.

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