ASSESSMENT OF WATER QUALITY OF SILISERH LAKE IN ALWAR, RAJASTHAN

Abstract

The present study was undertaken to assess water quality of Siliserh Lake in Alwar during the month of March 2018, and to assess its suitability for drinking, irrigation, and industrial usages using various indices. The suitability for drinking and irrigation were determined by comparing the obtained mean value with the BIS standards and prescribed indices. The water of the lake was found to be suitable for drinking for all the parameters, as all the parameters have their average value below the prescribed BIS standard. Slightly raised values were observed near Kishanpura and Ringaspura villages. Based on Piper classification, the water of Siliserh Lake was found to be CaHCO3 type followed by Ca-Mg-Cl type .The relative dominance of cations represented Mg > Ca > Na> K > Fe > Li trend, and anions represented HCO3- > Cl > NO3- > Dissolved SiO2 > SO42- > CO32- > PO43- trend which validated the the major composition type of water. Based on the concentration of nutrients (nitrogen and phosphorus), the lake was classified as eutrophic and is in the zone of transition from oligotrophic to eutrophic. The partition coefficient with value less than unity for phosphate concentration in sediments to its concentration in water confirmed that the lake is gradually moving from oligotrophic to eutrophic status. Based on concentration of organic impurities, it was observed that most of the organic matter is received through flushing of catchment during monsoon; and autochthonous for rest of the period with BOD and dissolved ammonia levels within the permissible limits for sustaining aquatic life. Various indices used to calculate suitability of lake water for irrigation indicated that the water is good for use in irrigation with the only exception of magnesium hazard owing to high concentration of magnesium. Since the soil around the lake is sandy and permeable, the water is found to be suitable for long term use in irrigation. Since the concentration of dissolved ions in water is less, the water is undersaturated with respect to dissolved salts. Use of such water in industries is safe since it doesn’t cause scaling. On the other hand, the water is found to be corrosive with respect to its chemical composition since the concentration of bicarbonate ions was almost three times higher than the concentration of magnesium ions. The FTIR study of sediments and geochemical classification of water revealed that silicate weathering is regulating the water chemistry and rock-water interaction (direct base exchange) is playing a major role in composition of dissolved ions in water.