International Research Journal of Environment Sciences_________________________________ ISSN 2319–1414Vol. 1(5), 62-68, December (2012) Int. Res. J. Environment Sci. International Science Congress Association 62 Water Quality Assessment of a Tropical Wetland Ecosystem with Special Reference to Backwater Tourism, Kerala, South IndiaVincy M.V., Brilliant Rajan and Pradeep Kumar A. P.3 School of Environmental Sciences, Mahatma Gandhi University, Kottayam, INDIA Assistant Professor, PG Department of Environmental Science, St. John’s College, Anchal, INDIA Reader, Department of Geology, University of Kerala, Kariavattom, INDIAAvailable online at: www.isca.in Received 07th November 2012, revised 25 November 2012, accepted 2 December 2012 Abstract Wetland ecosystems are estimated to cover more than 1,280 million hectares and deliver a wide range of ecosystem services that contribute to human well-beings. Degradation and loss have reduced the capacity of wetlands to provide sufficient amounts and quality of water. The continued degradation of wetlands, and more specifically the continued decline in water quantity and quality, will result in further impoverishment of human health especially for vulnerable people in developing countries. The waterborne pollutants (chemical and microbiological) have a major effect on human health and chemical pollutants accumulate in the food chain to the point where they harm people. Vembanad Kol Wetland ecosystem is one of the most attractive backwater systems in the world. Tourism is now flourishing on Vembanad Lake, especially in the Kumarakom area the southern part of the lake. As a result, many new tourism facilities (like resorts and hotels) are being built without concern for either the natural wetland system or the areas culture and heritage. Variables analysed for included air and water temperature, TDS, pH, EC, DO, BOD, total alkalinity, salinity, nitrate phosphate, hardness, sodium, potassium, calcium, and silicate. The microbial analysis of different samples consist of microbial colony count, MPN (most probable number), and the presence of enteric pathogenic organisms. The acceptable level of water quality is a minimum requisite for tourism activities in all tourism destinations. The continued degradation of wetlands specifically the continued decline in water quality will result in impoverishment of human health, especially for vulnerable people in developing countries. Keywords: Vembanad kol wetland ecosystem, kumarakom, tourism, physico-chemical and bacteriological analysis Introduction “Wetlands” have been defined as swamps and other damp areas of land but in common parlance the word is used interchangeably with “Lakes” which denotes a large body of water surrounded by land. However, internationally accepted term of wetlands describes them as “Area of Marsh, Fen, Peat land or water whether natural or artificial, permanent or temporary with water, that is static or flowing, fresh, brackish or salt including areas of marine water, the depth of which does not exceed 6 meters”. Wetlands are unique ecosystem having rich nutrient status and carrying capacity with immense production potential hence considered as food and fodder resources for human and its related allies. Ecologically wetlands are of great significant for an area as they support different food chain, food webs, regulate hydrological cycle, recharge ground water, trapping of energy and shelter to large numbers of flora and fauna having great ecological and economical value2,3. The value of the world’s wetlands are increasingly receiving due attention as they contribute to a healthy environment in many ways. They retain water during dry periods, thus keeping the water table high and relatively stable. During periods of flooding, they mitigate flood and to trap suspended solids and attached nutrients. Thus, streams flowing into lakes by way of wetland areas will transport fewer suspended solids and nutrients to the lakes than if they flow directly into the lakes. The removal of such wetland systems because of urbanization or other factors typically causes lake water quality to worsen. In addition, wetlands are important feeding and breeding areas for wildlife and provide a stopping place and refuge for waterfowl. As with any natural habitat, wetlands are important in supporting species diversity and have a complex of wetland values. The study has been conducted in the Kumarakom region (937’57”- 9 38’21”N Latitude, 76 25’11”- 76 25’06”E Longitude) of Vembanad-Kol wetland of Kerala, along the southwest coast of India. Vembanad Lake, which is connected to Arabian sea through Cochin estuary, is the largest brackish, tropical wetland ecosystem, which is of extraordinary importance for its hydrological function, biodiversity and rich fishery resources. Kumarakom is situated on the eastern banks of Vembanad Lake. Vembanad serves as a habitat for a variety of fin and shell fish, and a nursery of several species of aquatic life. Mangrove is found to grow in the Kumarakom region. The Vembanad Lake was declared as a Ramsar Site in November 2002. There are a number of tourist resorts nestling on its banks. Vembanad bird sanctuary is located at Kumarakom and International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 62-68, December (2012)Int. Res. J. Environment Sci. International Science Congress Association 63 Pathiramanal, where a large number of tourists congregate during October-March every year - it being the peak season for visiting these bird sanctuaries. The Thanneermukkom Barrage is constructed across a narrow portion of Vembanad Lake between Thanneermukkom in the west and Vechoor in the east. The 1252 m long barrage is planned with 93 vents each 12.15 m X 5.47 m. Material and Methods Two different sampling stations of Vembanad Lake and Kumarakom wetland namely were selected. Water samples were collected from both stations at different sites. The physicochemical parameters are determined from sampling done during three seasons – pre-tourism (August-October), tourism (November - February) and post-tourism (April-May) for five years from 2008-2012. The water samples were collected in sterile glass bottles such that its neck is below the water surface so as to avoid the inclusion of atmospheric oxygen. Sampling and physicochemical and bacteriological investigation was carried out according to standard methods. Figure-1 Study area map - Vembanad lake south to Thaneermukkam Barrage and locations of sampling sitesTable-1Details regarding the physico-chemical analysis of water Sl. No. Parameters Analyzed Unit Methods/Instruments A. Physico-Chemical Parameters 1 Air temperature o C Thermometer 2 Water temperature o C Thermometer 3 TDS ppm TDS meter 4 Conductivity mS Conductivity meter 5 pH pH meter 6 Chloride mg/l Argentometry 7 Salinity ppt Argentometric Method 8 Alkalinity mg/l Titrimetry 9 Hardness mg/l EDTA titrimetry 10 DO mgO 2 /l Winkler method 11 BOD mgO 2 /l 5 day BOD test 12 Nitrate mg/l Brucine method 13 Silicate mg/l Silicomolybdate method 14 Phosphate mg/l Stannous chloride method 15 Sodium mg/l Flame photometry 16 Potassium mg/l Flame photometry B. Bacteriological Parameters 17 Faecal coliforms MPN/100 ml Multiple Tube Fermentation 18 Faecal streptococci MPN/100 ml Multiple Tube Fermentation Table-2 Identification of the source of faecal pollution using FC/FS ratio Sl. No. Source FC/FS ratio 1 Man 4.4 2 Duck 0.6 3 Sheep 0.4 4 Chicken 0.4 5 Pig 0.4 6 Cow 0.2 7 Turkey 0.1 (After USEPA, 1978; Geldreich, E. E., 1974)6,7 International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 62-68, December (2012)Int. Res. J. Environment Sci. International Science Congress Association 64 Calculation of FC/FS ratio: FC/FS ratios are required to identify the source of faecal contamination. This has been carried out as per the table given in table 2. Results and Discussion Temperature: The maximum water temperature of the Vembanad Lake (33°C) was observed during tourism and post-tourism seasons and the minimum water temperature (27°C) was observed during pre-tourism . The water temperature of the river systems and canals indicate maximum values during pre-tourism and tourism seasons where as minimum values were recorded during the post-tourism. The variation in water temperature may be due to different timing of collection and the influence of season. Temperature controls behavioral characteristics of organisms, solubility of gases and salts in water. Fecal contamination in the lake water may increase due to tourism activities and decomposition of fecal matter in turn increases the water temperature. Fecal coliforms were (�2400/100 ml) observed high in the lake ecosystems whereas the rivers and canals showed less fecal coliforms (150-1100/100 ml) which substantiate the above finding. Water temperature of the lake showed positive correlation with pH (r = 0.55, p0.05), EC (r = 0.51, p0.05), TDS and BOD (r = 0.57, p0.05). It showed negative correlation with alkalinity (r = -0.3, p0.01) and DO (r = -0.58, p0.05). Water temperature of the freshwater systems showed positive correlation with DO (r = 0.79, p0.05). It showed negative correlation with EC (r = -0.86, p0.05), TDS (r = -0.8, p0.05) and BOD (r = -0.81, p0.05). pH: In general the pH was within the limits of the standard values. For drinking water, a pH range of 6.0 – 8.5 is recommended. It has been mentioned that the increasing pH appear to be associated with increasing use of alkaline detergents in residential areas and alkaline material from wastewater in industrial areas10. pH values recorded in the river water is in agreement with the pH values for other freshwater systems of Thiruvananthapuram District11 and elsewhere in Kerala12. pH of river water showed negative correlation with silicate (r = -0.54, p0.05). pH of the lake showed positive correlation with EC (r = 0.621, p0.05), TDS (r = 0.69, p0.05), phosphate (r = 0.32, p0.01), K (r = 0.33, p0.01) and BOD (r = 0.74, p0.05). It showed negative correlation with total alkalinity (r = -0.41, p0.05) and DO (r = -0.5, p0.05). Conductivity: Conductivity is a good and rapid method to measure the total dissolved ions and is directly related to total solids. Higher the value of dissolved solids, greater the amount of ions in water13. Conductivity values were found to be the highest in the post-tourism period in both the sampling stations. Almost all the conductivity values fell within the “no effect” range of 0-70 S/cm for drinking water use14. This indicates that no adverse health effects associated with the electrical conductivity of the water were expected. There was a positive correlation between conductivity and pH (r = 0.62, p0.05), TDS (r = 0.89, p0.05), total hardness and magnesium hardness (r = 0.43, p0.05), calcium hardness (r = 0.33, p0.05), potassium (r = 0.57, p0.05) and BOD (r = 0.67, p0.05) in the lake systems. It showed negative correlation with alkalinity (r = -0.42, p0.05) and DO (r = -0.6, p0.05). In the river water, conductivity showed positive correlation with TDS (r = 0.94, p0.05), silicate (r = 0.48, p0.01), K (r = 0.49, p0.01) and BOD (r = 0.5, p0.01). Negative correlation was set up with DO (r = -0.55, p0.05). This was expected because the properties of conductivity are governed by the characteristics of the constituents inorganic salts dissolved in water. Total alkalinity: The alkalinity of water is its capacity to neutralize acids. Alkalinity of water is a measure of weak acid present in it and of the cations balanced against them15. Total alkalinity of water is due to presence of mineral salt present in it. It is primarily caused by the carbonate and bicarbonate ions16. The alkalinity value of both the stations was found to be within the permissible limit of WHO and BIS standards. Alkalinity showed positive correlation with DO (r = 0.58, p0.05) in the lake systems and BOD (r = 0.62, p0.05) in the river systems. It was negatively correlated with pH (r = -0.41, p0.05), EC (r = -0.42, p0.05), TDS (r = -0.59, p0.05), salinity (r = -0.29, p0.05) and BOD (r = -0.68, p0.05). Total hardness: Total hardness is the parameter of water quality used to describe the effect of dissolved minerals (mostly Ca and Mg), determining suitability of water for domestic, industrial and drinking purpose attributed to presence of bicarbonates, sulphates, chloride and nitrates of calcium and magnesium17. The total hardness level was found exceeding the WHO and BIS permissible limits in both the stations. The total hardness is mainly due to Ca; Mg and eutrophication. The water containing excess hardness is not desirable for potable water. It consumes more soap during washing of clothes. Total hardness levels were high in the lake systems when compared to river systems and canals. The above verdict has been supported with correlation studies showing strong positive correlation with CaH (r = 0.998, p0.05), MgH (r = 0.98, p0.05), nitrate (r = 0.87, p0.05), sodium (r = 0.89, p0.05) and silicate (r = 0.63, p0.05) in the lotic systems and with EC (r = 0.43, p0.05), CaH (r = 0.93, p0.05), MgH (r = 0.85, p0.05) and K (r = 0.62, p0.05) in the lentic system. Calcium Hardness: Calcium is an important micronutrient in an aquatic environment Hardness of the river water is of considerable significance in connection with the discharge of the sewage and industrial effluent containing pollution, as indicated by variations in the concentration of the hardness of the water18. The concentration of Ca Hardness exceeded the permissible limits in all the stations and seasons. CaH showed positive correlation with EC (r = 0.35, p0.01), TH (r = 0.93, p0.05), MgH (r = 0.82, p0.05) and K (r = 0.64, p0.05) in the lake systems. It showed positive correlation with TH (r = 0.99, p0.05), MgH (r = 0.95, p0.05), nitrate (r = 0.87, p0.05), sodium (r = 0.88, p0.05) and silicate (r = 0.63, p0.05) in the river systems. International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 62-68, December (2012)Int. Res. J. Environment Sci. International Science Congress Association 65 Magnesium Hardness: Magnesium as co factor for various enzymatic transformations within the cell especially in the trans-phosphorylation in algal, fungal and bacterial cell19. The concentration of Ca Hardness exceeded the permissible limits in all the stations and seasons. MgH showed positive correlation with EC (r = 0.43, p0.01), TH (r = 0.853, p0.05), CaH (r = 0.82, p0.05) and K (r = 0.64, p0.05) in the lake systems. It showed positive correlation with TH (r = 0.98, p0.05), CaH (r = 0.95, p0.05), nitrate (r = 0.85, p0.05), sodium (r = 0.89, p0.05) and silicate (r = 0.62, p0.05) in the river systems. DO: The value of Dissolved Oxygen is remarkable in determining the water quality criteria of an aquatic system. In the system where the rates of respiration and organic decomposition are high, the DO values usually remain lower than those of the system, where the rate of photosynthesis is high20. The DO was within the limits of the standard values (WHO and BIS). The results were in concurrence of studies performed by Varunprasath and Daniel14. Mishra and Tripathi21observed mean value of dissolved oxygen ranging from 1.8 to 5.9 mgl-1 of river Ganga at Varansi. It showed negative correlation with BOD (r = -0.88, p0.05), EC (r = -0.55, p0.05), TDS (r = -0.58, p0.05) and phosphate (r = -0.75, p0.05) in the freshwater systems. It showed negative correlation with BOD (r = -0.83, p0.05), EC (r = -0.57, p0.05), TDS (r = -0.74, p0.05) and pH (r = -0.5, p0.05) in the lake systems. BOD: Biochemical Oxygen Demand is usually defined as the amount of oxygen required by bacteria in stabilizing the decomposable organic matter. The biodegradation of organic materials exerts oxygen tension in the water and increases the biochemical oxygen demand22. BOD gives an idea about the extent of pollution. BOD has been a fair measure of cleanliness of any water on the basis that values less than 1-2 mg/l are considered clean, 3 mg/l fairly clean, 5 mg/l doubtful and 10 mg/l definitely. BOD was found to be exceeding the permissible limits in all the stations. Increase in BOD levels was observed mainly in the post-tourism periods. BOD was negatively correlated with DO (r = -0.83, p0.05) in the lake systems and (r = -0.88, p0.05) in the river systems. It showed positive correlation with water temperature (r = 0.57, p0.05), pH(r = 0.74, p0.05), EC (r = 0.67, p0.05) and TDS (r = 0.82, p0.05) in the Vembanad lake. Nitrate: The main sources of nitrate in water are human and animal waste, industrial effluent, use of fertilizers and chemicals, silage through drainage system23. The amount of nitrates in both the stations was found to be much below the accepted drinking water standards (20 ppm – ICMR 1975; 45 ppm – ISI 1991). It showed positive correlation with TH (r = 0.87, p0.05), CaH (r = 0.87, p0.05), MgH (r = 0.85, p0.05), silicate (r = 0.84, p0.05), sodium (r = 0.61, p0.05), potassium (r = 0.51, p0.05) and DO (r = 0.52, p0.05) in the river systems. It was negatively correlated with phosphate (r = -0.77, p0.05). Nitrate showed insignificant correlation with all the parameters in the lake systems. Phosphate: The increased application of fertilizers, use of detergents and domestic sewage greatly contribute to the heavy loading of phosphorous in the water24. The BIS (Bureau of Indian Standard) suggested the limit of phosphate is 0.1mg/l. Phosphate levels were high in all the sampling sites in all the seasons. Bacteriological Parameters: A total of 17 bacterial genera were identified in water samples. Thirty Gram positive bacterial species were identified in water samples, which were distributed in 5 genera, such as Bacillus, Listeria, Kurthia, Carnobacteriumand Staphylococci. While 40 species of Gram negative bacteria were identified in water of Kumarakom region of Vembanad lake. About 41% of bacterial isolates from water were identified as Bacillus. Twenty Bacillus species were identified from water. Bacillus subtilis and Bacillus cereus was found to be the most dominant Nitrate reductase was detected in 40 % of Bacillus isolates from water. While 78% of Bacillus isolates from water have protease activity. All the Bacillus isolates from water samples revealed amylase activity. Tyrosinase was detected in 13% of Bacillus isolates from water. About 15% of Bacillus isolates from water samples of Kumarakom lake were also survived up to 55C. L. ivanovii, L. murrayii and L. grayi were identified from water samples. K. zopfii, C. gallinarum, S. aureus and S. epidermidiswere identified from water. -haemolytic activity was detected in 40% of Listeria isolates from water. Coagulase activity was detected in 50% of Staphylococciisolates from water. Four species of Enterobacteriaceae were identified in water of Kumarakom lake. Enterobacter cloacae was the dominant one in water. 17 species of Vibrio were identified from water samples. V. coralliilyticus was identified from water samples collected from almost all the stations. More diverse Vibrio species were identified in water during the month of June. Various species of Aeromonas identified in this study were isolated from water samples collected during warmer times of the year. Five species of Aeromonas and Alcaligenes and two species of Pseudomonas were identified from water in the study area. Conclusion The variations in the water quality parameters are evident in all the physico – chemical parameters examined. The present study concluded that river water of study area was moderately polluted in respect to analyzed parameters. pH, total hardness, chloride and fluoride were found within permissible limit but the higher values of BOD in present study attributed river water was not fit for drinking purpose. It needs to aware local villagers to safeguard the precious river and its surrounding. International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 62-68, December (2012)Int. Res. J. Environment Sci. International Science Congress Association 66 Table-3 Physico-chemical parameters of Vembanad lake Parameters Units Seasons Mean±±SD Air temp. C PRE 35.51.87 TOURISM 291.26 POST 28.170.75 Water temp. C PRE 31.670.52 TOURISM 30.420.49 POST 26.50.55 pH PRE 6.850.47 TOURISM 6.640.94 POST 6.630.1 EC mS PRE 1.670.35 TOURISM 2.550.19 POST 3.130.16 TDS mg/l PRE 1449.3383.66 TOURISM 1887.8337.1 POST 2051.1760.26 Salinity ppt PRE 7.581.07 TOURISM 7.751.08 POST 8.081.32 Total Alkalinity mg/l PRE 48.334.08 TOURISM 255.48 POST 5010.95 Total Hardness mg/l PRE 371.83101.2 TOURISM 403.6796.55 POST 417101.49 Calcium Hardness mg/l PRE 249.8362.38 TOURISM 273.1768.6 POST 28066.76 Magnesium Hardness mg/l PRE 124.8335.06 TOURISM 133.6732.71 POST 137.6735.79 Phosphate ppm PRE 0.10.07 TOURISM 0.130.08 POST 0.170.08 Nitrate ppm PRE 5.521.34 TOURISM 5.521.4 POST 5.651.33 Silicate ppm PRE 2.670.5 TOURISM 2.850.51 POST 3.070.48 Sodium mg/l PRE 10936.94 TOURISM 11516.38 POST 136.8318.14 Potassium mg/l PRE 73.3327.33 TOURISM 87.8326.27 POST 97.6723.42 DO mg/l PRE 50.64 TOURISM 4.670.62 POST 3.330.52 BOD mg/l PRE 4.030.76 TOURISM 3.450.31 POST 5.930.33 Table-4 Physico-chemical parameters of Kumarakom Parameters Units Seasons Mean±±SD Air temp. C PRE 35.51.87 TOURISM 291.26 POST 28.170.75 Water temp. C PRE 31.670.52 TOURISM 30.420.49 POST 26.50.55 pH PRE 6.850.47 TOURISM 6.640.94 POST 6.630.1 EC mS PRE 1.670.35 TOURISM 2.550.19 POST 3.130.16 TDS mg/l PRE 1449.3383.66 TOURISM 1887.8337.1 POST 2051.1760.26 Salinity ppt PRE 7.581.07 TOURISM 7.751.08 POST 8.081.32 Total Alkalinity mg/l PRE 48.334.08 TOURISM 255.48 POST 5010.95 Total Hardness mg/l PRE 371.83101.2 TOURISM 403.6796.55 POST 417101.49 Calcium Hardness mg/l PRE 249.8362.38 TOURISM 273.1768.6 POST 28066.76 Magnesium Hardness mg/l PRE 124.8335.06 TOURISM 133.6732.71 POST 137.6735.79 Phosphate ppm PRE 0.10.07 TOURISM 0.130.08 POST 0.170.08 Nitrate ppm PRE 5.521.34 TOURISM 5.521.4 POST 5.651.33 Silicate ppm PRE 2.670.5 TOURISM 2.850.51 POST 3.070.48 Sodium mg/l PRE 10936.94 TOURISM 11516.38 POST 136.8318.14 Potassium mg/l PRE 73.3327.33 TOURISM 87.8326.27 POST 97.6723.42 DO mg/l PRE 50.64 TOURISM 4.670.62 POST 3.330.52 BOD mg/l PRE 4.030.76 TOURISM 3.450.31 POST 5.930.33 International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 62-68, December (2012)Int. Res. J. Environment Sci. International Science Congress Association 67 Table-5 Physico-chemical parameters of Kumarakom AT WT pH EC TDS SAL ALK TH CaH MgH PHOS NITR SIL SOD POT DO BOD AT 1 0.71(**) 0.13 - 0.88(**) - 0.92(**) - 0.23 0.31 - 0.2 - 0.17 - 0.2 - 0.31 - 0.03 - 0.29 - 0.21 - 0.41 0.55 (*) - 0.36 WT 0.71(**) 1 0.2 - 0.86(**) - 0.8(**) - 0.19 - 0.31 - 0.14 - 0.13 - 0.11 - 0.39 - 0.02 - 0.3 - 0.18 - 0.34 0.79(**) - 0.81(**) pH 0.13 0.21 1 - 0.36 - 0.4 - 0.17 0.12 - 0.2 - 0.27 - 0.11 0.19 - 0.39 - 0.54(*) - 0.03 - 0.37 0.04 - 0.02 EC - 0.88(**) - 0.86(**) - 0.36 1 0.94 (**) 0.29 - 0.08 0.39 0.38 0.38 0.2 0.24 0.48 (*) 0.41 0.49(*) - 0.55(*) 0.5(*) TDS - 0.92(**) - 0.8(**) - 0.4 0.94(**) 1 0.18 - 0.22 0.3 0.3 0.25 0.21 0.14 0.38 0.28 0.47(*) - 0.58(*) 0.45 SAL - 0.23 - 0.19 - 0.17 0.29 0.18 1 0.344 0.1 0.07 0.14 0.13 0.16 0.15 0.17 0.79(**) - 0.18 0.22 ALK 0.31 - 0.31 0.12 - 0.08 - 0.22 0.34 1 - 0.11 - 0.11 - 0.12 0.12 - 0.02 - 0.01 - 0.03 0.14 - 0.33 0.62(**) TH - 0.2 - 0.14 - 0.2 0.39 0.3 0.1 - 0.11 1 0.99(**) 0.98(**) - 0.72(**) 0.87(**) 0.63(**) 0.89(**) 0.45 0.42 - 0.21 CaH - 0.17 - 0.13 - 0.27 0.38 0.3 0.07 - 0.11 0.99(**) 1 0.95(**) - 0.75(**) 0.87(**) 0.63(**) 0.88(**) 0.43 0.42 - 0.22 MgH - 0.2 - 0.11 - 0.11 0.38 0.25 0.14 - 0.12 0.98(**) 0.95(**) 1 - 0.63(**) 0.85(**) 0.62(**) 0.89(**) 0.44 0.43 - 0.22 PHOS - 0.31 - 0.39 0.19 0.2 0.21 0.13 0.12 - 0.72(**) - 0.75(**) - 0.63(**) 1 - 0.77(**) - 0.43 - 0.52(*) - 0.14 - 0.75(**) 0.52(*) NITR - 0.03 - 0.02 - 0.39 0.24 0.14 0.16 - 0.02 0.87(**) 0.87(**) 0.85(**) - 0.77(**) 1 0.84(**) 0.61(**) 0.51(*) 0.52(*) - 0.26 SIL - 0.29 - 0.3 - 0.54(*) 0.48(*) 0.38 0.15 - 0.01 0.63(**) 0.63(**) 0.62(**) - 0.43 0.84(**) 1 0.37 0.41 0.17 0.02 SOD - 0.21 - 0.18 - 0.03 0.41 0.28 0.172 - 0.03 0.89(**) 0.88(**) 0.89(**) - 0.52(*) 0.61(**) 0.37 1 0.31 0.25 - 0.09 POT - 0.41 - 0.34 - 0.37 0.49(*) 0.47(*) 0.79(**) 0.14 0.45 0.43 0.438 - 0.14 0.51(*) 0.41 0.31 1 - 0.1 0.16 DO .55(*) 0.79(**) 0.04 - 0.55(*) - 0.58(*) - 0.18 - 0.33 0.42 0.42 0.43 - 0.75(**) 0.52(*) 0.17 0.25 - 0.1 1 - 0.88(**) BOD - 0.36 - 0.81(**) - 0.02 0.5(*) 0.448 0.22 0.62(**) - 0.24 - 0.22 - 0.22 0.52(*) - 0.26 0.02 - 0.09 0.16 - 0.88(**) 1 Table-6 Physico-chemical parameters of Vembanad lake AT WT pH EC TDS SAL ALK TH CaH MgH PHOS NITR SIL SOD POT DO BOD AT 1 0.63(**) 0.58(**) 0.46(**) 0.56(**) - 0.18 - 0.32(*) 0.1 0.03 0.1 0.32(*) - 0.08 0.08 0.16 0.11 - 0.63(**) 0.62(**) WT 0.63(**) 1 0.55(**) 0.51(**) 0.57(**) - 0.007 - 0.3(*) 0.14 0.11 0.19 0.21 0.01 0.05 0.09 0.25 - 0.582(**) 0.57(**) pH 0.58(**) 0.55(**) 1 0.62(**) 0.69(**) - 0.22 - 0.41(**) 0.2 0.19 0.24 0.32(*) 0.17 - 0.1 0.26 0.33(*) - 0.501(**) 0.74(**) EC 0.46(**) 0.51(**) 0.62 (**) 1 0.89(**) - 0.13 - 0.42(**) 0.43(**) 0.35(*) 0.43(**) 0.22 0.25 - 0.13 0.22 0.57(**) - .0573(**) 0.67(**) TDS 0.56(**) 0.57(**) 0.69 (**) 0.89(**) 1 - 0.11 - 0.59(**) 0.22 0.18 0.19 0.35(*) 0.18 0.11 0.15 0.38(**) - 0.741(**) 0.82(**) SAL - 0.18 - 0.01 - 0.22 - 0.13 - 0.11 1 - 0.29(*) - 0.07 - 0.08 - 0.09 - 0.09 0.002 - 0.13 0.05 - 0.19 0.06 - 0.06 ALK - 0.32(*) - 0.3(*) - 0.41(**) - 0.42(**) - 0.59(**) - 0.29(*) 1 0.06 0.08 0.13 - 0.21 0.09 - 0.14 - 0.1 - 0.12 058(**) - 0.68(**) TH 0.1 0.14 0.2 0.43(**) 0.22 - 0.07 0.06 1 0.93(**) 0.85(**) - 0.25 0.15 - 0.34(*) - 0.17 0.62(**) - 0.03 0.16 CaH 0.03 0.11 0.19 0.35(*) 0.18 - 0.08 0.08 0.93(**) 1 0.82(**) - 0.24 0.17 - 0.22 - 0.19 0.53(**) 0.03 0.11 MgH 0.1 0.19 0.24 0.43(**) 0.19 - 0.09 0.13 .846(**) 0.82(**) 1 - 0.16 0.11 - 0.4(**) - 0.03 0.64(**) - 0.004 0.1 PHOS 0.32(*) 0.21 0.32 (*) 0.22 0.35(*) - 0.09 - 0.21 - 0.25 - 0.24 - 0.16 1 - 0.05 0.13 0.34(*) - 0.22 - 0.23 0.33(*) NITR - 0.08 0.01 0.17 0.25 0.18 0.002 0.09 0.15 0.17 0.11 - 0.05 1 0.07 - 0.16 0.12 0.17 \ 8 0.128 SIL 0.08 0.05 - 0.1 - 0.13 0.11 - 0.13 - 0.14 - .34(*) - 0.22 - 0.4(**) 0.13 0.07 1 - 0.24 - 0.39(**) - 0.16 0.09 SOD 0.16 0.09 0.24 0.22 0.15 0.05 - 0.1 - 0.17 - 0.19 - 0.03 0.34(*) - 0.16 - 0.24 1 - 0.01 - 0.03 0.09 POT 0.11 0.25 0.33(*) 0.57(**) 0.38(**) - 0.19 - 0.12 0.62(**) 0.53(**) 0.64(**) - 0.22 0.12 - 0.34(**) - 0.01 1 - 0.13 0.26 DO - 0.63(**) - 0.58(**) - 0.5(**) - 0.57(**) - 0.74(**) 0.06 0.58(**) - 0.03 0.03 - 0.004 - 0.23 0.18 - 0.16 - 0.03 - 0.13 1 - 0.83(**) BOD 0.62(**) 0.57(**) 0.74(**) 0.67(**) 0.82(**) - 0.06 - 0.68(**) 0.156 0.11 0.1 0.33(*) 0.13 0.09 0.09 0.26 - 0.83(**) 1 ** Correlation is significant at the 0.01 level (2-tailed). * Correlation is significant at the 0.05 level (2-tailed). References 1.Gupta M.B., Vijayan L., Sandaliyan S. and Sridharan N., Status of Wetlands and Wetland Birds in Coimbatore, Trichy, Perambalore and Thiruvarur Districts in Tamil Nadu, India. World Journal of Zoology, 6(2), 154-158 (2011) 2.Bennet G.W., Management of artificial lakes and ponds. Reinhold. New York, USA. 283 (1962)3.Oglesby R.T., Management in the lacustrine Fisheries in the tropics, Fisheries, 10(2), 16-19 (1985)4.Prasad S.N., Ramachandra T.V., Ahalya N., Sengupta T., Kumar A., Tiwari A.K., Vijayan V.S. and Vijayan, L., Conservation of wetlands of India – a review. Tropical Ecology, 43(1), 173-186 (2002)5.APHA, Standard methods for the examination of water and wastewater (20th ed.). Washington, DC: American Public Health Association, American Water Works Association and Water Pollution Control Federation, (1998)6.Geldreich E. E., Buffalo Lake recreational water quality: a study on bacteriological data interpretation, Water Research, : 913-921 (1974)7.U.S. EPA, Microbiological Methods for Monitoring the Environment: Water and Wastes. Envir. Monitor and Supp. Lab., Off. Res and Dev., U.S. Envir. Protect. Agen., Cincinnati, Ohio, (1978)8.Jayaraman P.R., Ganga Devi T. and Vasudena Nayar T., Water quality studies on Karamana River, Thiruvananthapuram District South Kerela, India. Poll Res., 22(1), 89 –100 (2003)9.De A.K., Environmental chemistry (4th edn.), New Delhi, India: New Age International Publishers, (232)(2002) International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 62-68, December (2012)Int. Res. J. Environment Sci. International Science Congress Association 68 10.Chang H., Spatial analysis of water quality trends in the Han River Basin, South Korea, Water Research, 42(13), 3285-3304 (2008)11.Krishnakumar A., Hydrogeochemistry of Vellayani Freshwater lake with special reference to drinking water quality. M. Phil Thesis, University of Kerala, India, (1998)12.Sreejith S., Mani R. and Padmalal D., Granulometric of the sediments of Sasthamkotta and Vellur Lakes, Kerala: Implication of hydrodynamic responses on lacustrine sediments. J. Ind. Assoc. Ediment., 17, 251-262 (1998)13.Bhatt L.R., Lacoul P., Lekhak H.D. and Jha P.K., Physicochemical characteristics and phytoplankton of Taudha Lake Kathmandu. Poll. Res., 18(14), 353-358 (1999)14.Sverdrap H.H., Johnson M.W. and Fleming R.H., The Oceans: Their physics, chemistry and general biology. Prentice Hall, New York, (1942)15.Singh, M.R., Gupta, Asha and Beeteswari, K.H., Physico-chemical properties of water samples from Manipur river system, India. J. Appl. Sci. Environ. Manage., 14(4), 85-89 (2010)16.Taylor E.W., The examination of water and water supplies, J. and A Churchill Ltd, London, (1949)17.Rai H. Limnological observation on the different rivers and lakes in the Ivory Coast. Hydrobiologia, 44(213), 301-317 (1974)18.World Health Organization, Guidelines for drinking water quality, Geneva: WHO (2nd edition), (1984)19.Mishra A., Mukherjee A. and Tripathi B.D., Seasonal and Temporal Variation in Physico-Chemical and Bacteriological Characteristics of River Ganga in Varansi. Int. J. Environ. Res., 3(3), 395-402 (2009)20.Mishra A. and Tripathi B.D., Seasonal and temporal variation in physico-chemical and bacteriological characteristics of river Ganga in Varansi, Cuur. World Environ., 2(2), 149-154 (2007)21.Abida B. and Harikrishna, Study on the Quality of Water in Some Streams of Cauvery River, E- Journal of Chemistry, 5(2), 377-384 (2008)22.Gupta P., Choudhary R. and Vishwakarma M., Assessment of water quality of Kerwa and Kaliasote rivers at Bhopal district for irrigation purpose, International Journal of Theoretical and Applied Sciences, 1(2), 27-30 (2009)23.Golterman H.L., Physiological Limnology, Elsevier Scientific Publication Co. N.Y., (1975)24.Water Resources Commission (WRC), Ghana Raw Water Criteria and Guidelines, Domestic Water, CSIR-Water Research Institute, Accra, Ghana, (1)(2003)25.APHA, Standard Methods for Examination of Water and Wastewater. 19th Edn., American Public Health Association, Washington, D.C., (1995)26.WHO, Recommendations, Water and Sanitation, Guidelines for Drinking Water Quality, Geneva: WHO, (1)(1975)