Using the Index of Biological Intergrity Ibi for Assessing the Water Quality of the Thu Bon Lower River in Quang Nam Province

The Thu Bon lower river is one of the basins that are at risk of contamination. The physical-chemical monitoring methods in use are still faced with limitations due to lack of access to biological information. Biomonitoring is now regarded as one of the effective tools for environmental assessment, in which using an index of biological intergrity IBI combined with fish as a biological indicator has obtained many achievements in the world. In this paper, we use the IBI to assess the water quality of the Thu Bon lower river in February 2014. The research results have identified 95 species of fish which belong to 40 families and 13 orders. The IBI score ranges from 38 to 52 points, which corresponds to the water quality levels from “fairly clean water” to “slightly dirty water”. This proves that the water quality of the Thu Bon lower river is showing signs of contamination