This study aims to assess the environmental conditions of selected water bodies in western Nghe An province, using macro-invertebrates as bio-indicators. Field collection from 16 sampling sites in April 2013 has yielded 44 macro-invertebrate families that were included in the BMWPV1ET scoring system. Among 16 sampling sites, seven sites were classified at Oligosaprobe level (fairly clean), with ASPT scores from 6.0 to 7.0
five sites with ASPT scores between 5.4 and 5.9, were classified at beta-Mesosaprobe level (quite polluted)
four remaining sites with ASPT scores below 5.0 (between 3.3 and 4.7) were classified at alpha-Mesosaprobe level. At upstream sites, mostly in the core zone of Pu Mat National Park with little human impact, the water quality was still good, at Oligosaprobe level. In other areas, human activities (recreation, tourism, agriculture, construction) negatively affected the water quality, with pollution level classified at alpha-and beta-Mesosaprobe levels, however, still at acceptable levels.