RESUMO
It has been demonstrated by research that the most successful assessment methods have been based on the benthic macroinvertebrate communities. A lot of bio-indices have been applied to evaluate the water quality widely. However, most of them have got the rankings for the water quality assessment. In this study, based on the monitoring results of the benthic macroinvertebrate and the environmental parameters in the Lower Dongnai River System during three-year periods (2007 - 2009), the linear correlations among the most popular bio-indices and each environmental parameter were considered. These environmental variables having the most closed correlation with the biological indices were DO (dissolved oxygen), WQI (water quality index) and total nitrogen. From the analysis, the ranking of bio-indices using benthic macroinvertebrate for the Lower Dongnai River System were established. The findings proved that the ranking of bio-indices for water quality assessment can be used to evaluate the water quality for the Lower Dongnai River System.