Analysis of certain physico chemical parameters of river mara bharali in the sonitpur district of assam, india with special reference to its molluscan diversity

Rivers play a major role in integrating and organizing the landscape, and moulding the ecological setting of a basin. The present investigation was conducted in the remnants of old channel of Jia Bharali named as Mara Bharali at Tezpur in the Sonitpur district of Assam, India. Sampling stations were selected from Solmara Bridge (N-26º41'13.65" and E-92º48'59.32") near Tezpur University, Tezpur to Maithan (N-26º37'05.69" and E-92º49'34.34") where the river meets the river Brahmaputra. The temperature, pH and turbidity of the river water was found to be within the WHO permissible limit. However, Site-II, III and IV showed higher turbidity above permissible limits. During the post monsoon the TDS ranged between 700 – 1800 mg/L whereas during the winter the value was found to be between 600 – 1500 mg/L which was above the WHO permissible limit. DO values depleted in winter and was found to range between 1.8 – 4.2 mg/L. Free CO2 value was found to be maximum during monsoon at site II (Mara Bharali Bridge) at 57.2 mg/L. A total of 06 (six) molluscan species were recorded from the sampling sites during the period of study which indicates that productivity of the river is moderately rich. The molluscan community was represented by two classes, viz., Bivalvia and Gastropoda of which 01 species was Bivalvia and 05 species were Gastropoda.