International Science Community Association International Research Journal of Environmental Sciences 2319 - 1414 5 11 2016 11 22 Application of Family Biotic Index in Assessment of two Rivers Affected by Oil Pollution in Assam, India 35 40 EN Sahoo Jangyeswar 1 OUAT, Bhubaneswar, Odisha, India Behera Manoj Kumar 2 NR Management Consultants India Pvt. Ltd., Bhubaneswar, Odisha, India Bhange H.N. 1 Dept of SWE, CTAE, MPUAT, Udaipur, Rajasthan, India Singh P.K. 2 Dept of SWE, CTAE, MPUAT, Udaipur, Rajasthan, India Purohit R.C. 3 Dept of SWE, CTAE, MPUAT, Udaipur, Rajasthan, India Yadav K.K. 4 Dept of SWE, CTAE, MPUAT, Udaipur, Rajasthan, India Jain H.K. 5 Dept of Agril Statistics and Computer Applications, RCA, MPUAT, Udaipur, Rajasthan, India Jain Sudhir 6 Dept of Renewable Energy Sources, CTAE, MPUAT, Udaipur, Rajasthan, India Raut Somnath Anil 1 Environmental Science Department, School of Environment and Earth Sciences, North Maharashtra University, Jalgaon, India Thorat S.R. 2 Environmental Science Department, School of Environment and Earth Sciences, North Maharashtra University, Jalgaon, India Aryal Uttam 1 Golden Gate International College, Battisputali, Kathmandu, Nepal Adhikari Tirtha Raj 2 Central Department of Hydrology and Meteorology, Tribhuvan University, Kirtipur, Nepal Thakuri Sudeep 3 Golden Gate International College, Battisputali, Kathmandu, Nepal Rakhal Biplob 4 Genesis Consultants Pvt. Ltd, Lalitpur, Nepal Janmoni Moran 1 Dept. of Life Sciences, Dibrugarh University, Assam, India > Research Paper 2016 8 20 2016 11 22 By using Family Biotic Index (FBI) two rivers viz. Dhansiri and its tributary river Kaliani were assessed from March, 2012 to February, 2014, dividing the entire period into four seasons as pre monsoon, post monsoon and winter. These two rivers were affected since its operation from the year, 2000 by the Numaligarh Oil Refinery of Assam. In the study, 23 genera and 2 tribes (Chironomidae family) belonging to 25 families of macro invertebrates have been recorded belonging to ten orders, four classes and three phyla. The annual FBI values were found to be lowest for the control area of Kaliani and most of the macro invertebrates that were found in that control area were relatively pollution intolerant. On the other hand, the point of effluent discharge (S6) of contaminated area receiving the refinery effluents with the highest FBI value has shown “Very poor” water qualities with severe organic pollution likely as the most of contributing families were highly tolerant to organic pollution. Copyright@ International Science Community Association