Assessment of the water quality of Ghodaghodi lake using selected physicochemical parameters

Abstract

The physicochemical parameters of Ghodaghodi lake were investigated during pre-monsoon ( May, 2018) and Post-monsoon season ( November, 2018). Water samples for physicochemical parameters were collected and analyzed using standard methods. Four different sampling sites (I, II, III, and IV) were studied. Triplicate of water samples were collected from each site of Lake and physico-chemical characteristics, i.e. pH, temperature, depth, dissolved oxygen, total alkalinity, total hardness, conductivity, total dissolved matter, free CO 2 , nitrate and inorganic phosphorous were analyzed. Random sampling method was used. Altogether, 8 quadrats (four paired quadrats) were plotted in each site of the study area per season. Altogether 32 quadrats were laid down per season. Water samples were collected from the depth of 0.5 m within the 1m×1m quadrats. CO 2 , hardness, temperature and depth was also found to be high during pre-monsoon and these parameters have low values during post-monsoon. pH, conductivity, alkalinity, DO and TDS, value (±SD) was found to be high during post-monsoon with value and low during pre-monsoon. The average value of physicochemical parameters studied were water temperature (22.92°C), pH (7.69), DO (3.2 mg/L), electrical conductivity (180.71 μS/cm), TDS (91.43 ppm), Free CO 2 (128.29 mg/L),Total hardness (191.16 mg/L), Total alkalinity (177.41 mg/L), phosphate (0.33 mg/L) and nitrate (0.0.095 mg/L). Very low DO concentrations in lake indicated very stressful conditions for aquatic life forms. This is of great concern especially regarding the conservation of critically endangered gharial, vulnerable marsh crocodile, and many other fish species. The limnological status of the lake estimated in this study is of critical importance to implement management actions for the conservation and better management of Ghodaghodi lake, a wetland of western terai,Nepal.