عنوان مقاله [English]
Water is the most essential factor for life, and rivers are the main drinking source for human. Therefore, assessing the quality and management of rivers is essential for the protection and health of these rivers. Diatoms are one of the best monitoring tools used in European and American water quality monitoring programs. Due to the importance of diatoms in water quality assessment, the present study was designed and carried out to investigate the water quality of Karaj River based on diatom species and indicator diatoms for pollution. Diatom specimens were collected from the surface of the rocks at six stations along the river during 2011 to 2012 monthly. In this study, 128 species were identified and their relative abundance was calculated, of which 19 were dominant. Evaluation of water contamination based on minerals and biological oxygen demand showed that Karaj River water had moderate to very high pollution at the stations. The results of the ecology of the dominant species showed that most of these species increased with increasing organic and inorganic contamination and could be introduced as indicator diatoms for pollution. The present study is a baseline for future studies on diatom-based monitoring of mountainous rivers in the Alborz region.