Abstract

Water quality monitoring and assessment hasbecome a critical issue because it affects human and aquatic life.In recent years Beki River of Assam, India have encounteredserious threats which includes sand mining, use of fertilizers onthe river banks, uncontrolled fishing that have altered the waterquality of the river specially in the fish landing sites. These havecaused significant reduction in abundance of the fresh waterfishes in the region. This study identifies the parameters thatare responsible for decreasing the water quality in the six fishlanding sites of the river. The study shows low pH of the riverwater indicating its acidity nature. Decrease in Dissolvedoxygen (DO) during the monsoon in Dumnigh at, Sapakamaand Madulijar suggested poor quality of water indicating theslow rate of photosynthesis by phytoplankton present in theBeki River. The concentration of Iron in Gobardhana,Sapakama and Dumnigh at during post monsoon was higherthan the maximum limit of 0.3 mg/l. Concentration of nitratewas found to be higher than the limit of 45 mg/l in all thelanding sites except for Gobardhana due to application ofinorganic nitrogen fertilizers in the agricultural farm in theriver bank. Concentration of manganese, arsenic and lead wasfound to be higher than the maximum limit in the fish landingsites. The spatial variations of the major ions reflects theinfluence of various anthropogenic and lithology’s activities inthe river system.