Ecological response of macrobenthos in Jadjrud River by human sewages

This study was done in order to determine the pollution effects on growth of macrobenthoses in Jadjrud River, between Saeedabad area and Ghareboron village. Three stations considered for invertebrates sampling. Assessment of some parameters such as air and water temperature, BOD5, dissolved oxygen, and pH were done monthly along with invertebrate sampling. Total existence, EPT existence, Shanon-Winner diversity index and HFB1 were used in assessment of macrobenthoses. During experiment, air and water temperature were 1.3-32.5 and 3-25.1 °C, respectively. BOD5 was 3.9-9.98 mg L-1, dissolved oxygen 4.85-9.52 mg L-1, and pH 8.8-9.6. In benthic fauna assessment, 7 orders and 5 genera were known, where some resistant groups against pollution such as Diptera, families of chironomidae and gastropods were dominant in estuary zone of the river. Maximum and minimum EPT dominance were 45% in spring (station 3), and 34% in summer (station 2), respectively. The results of this study showed that the pollution in station 1 was considerable, station 2 highly polluted, and station 3 relatively polluted. Based on Helsinhophe index, water quality in first station was low, while in station 2 was highly low an in station 3 was relatively low.