Debashri Mondal, Joydeb Pal, Tarun Kanti Ghosh and Arun Kanti Biswas
The present study was carried out to assess the physico-chemical status of surface water of Mirik lake in Darjeeling from seven selected locations during October 2005 – September 2007. The highest and lowest air and water temperatures were recorded respectively during summer and winter months. The pH values, as found to be lower in Sites 1 and 2, may be due to regular discharge of waste water from major and minor drains. The highest and lowest electrical conductivities in summer and monsoon respectively were due to dehydration and dilution of rainwater at different times. DO values were found to be higher during monsoon and winter seasons, while lowest value was recorded in summer. DO showed a significant negative correlation with free CO2. The highest and lowest total alkalinity and total hardness values were found respectively during summer and monsoon. Chloride values were found to be highest during winter and the lowest value was recorded during monsoon. Higher BOD values were recorded at Sites 1, 2 and 6. All the parameters varied significantly among sites and seasons. Public awareness is very much important to control the discharge of wastes into the lake and long term scientific monitoring is necessitated to evaluate the status of the lake for its longevity.