Evaluation of the physico-chemical characteristics of river Varuna at Varanasi, India.

In present investigation an attempt was made to assess variation in physico-chemical characteristics of river Varuna at Varanasi. The water samples were collected monthly from five sites during January to December 2009 and analyzed for physico-chemical properties. The investigation showed variation in temperature (18.5-32.5 degrees C), transparency (13.5-77.0cm), pH (8.0-8.8), alkalinity (96-486 mgl(-1)), free CO2 (1.6-64 mg l(-1)), DO (0.12-8.4 mg l(-1)), BOD (3.6-116.5 mg l(-1)), COD (5.9-225.4 mg l(-1)), chloride (11-80 mg l(-1)), nitrate (0.036-0.996 mg l(-1)) and phosphate (0.06-1.36 mg l (-1)). From the investigation it is clear that there was marked variation in different parameters at different sites during the different months of the year. The site-5 was found to be highly polluted (BOD 116.5 mg l(-1)) whereas the site-1 (BOD 3.6 mg l(-1)) was the least polluted.