Development of multimetric index based on benthic macroinvertebrate for water quality assessment of Jajrood River in Iran

Increased anthropogenic disturbances in river ecosystems has led to a reduction in the biodiversity of rivers. The purpose of this study was to develop a multimetric index based on benthic macroinvertebrate for water quality assessment of Jajrood River. Biological and physicochemical sampling from seven stations was performed in the upstream basin of the river, located in the northeast of Tehran. Therefore, for the development of the MMIJ (Multimetric Macroinvertebrate Index Jajrood upstream) index, as a complementary tool in analyzing the physicochemical parameters, the data and indices calculated in the first two years (2011 & 2012) were used and validated with the data of the third year (2013). So, 24 biological indices were selected. Range, stability, sensitivity, responsiveness (to the anthropogenic impact gradient), and redundancy were tested on indices. Finally, the five indices including FBI, MMIF, NJIS, Shannon-Wiener, and Margalef from four tests were performed for the development of the MMIJ multimetric index. Each index was given a values of 1, 3, and 5 about its score, and then this index was obtained with a sum of calculated scores. As a result, the calculated indices in the third year were valued according to the calibration of the five biological indices, and the water quality of the seven stations was determined. This study showed that MMIJ multimetric index had a high sensitivity to organic pollutants and was suitable for use in national monitoring and assessment programs in the Jajrood River basin.