Biological assessment of water quality in Chaohu Lake watershed:A case study of benthic macroinvertebrate.

Due to the long-term exposure to natural environment,benthic macroinvertebrate can integrate the environmental physical,chemical,and biological information at different time scales,and reflect the damaged characteristics under the synergistic effects of pollutants,having been widely used in water health assessment.To understand the present status of water pollution in Chaohu Lake watershed,Anhui Province of East China,an investigation on the benthic macroinvertebrate in the watershed was carried out in April 2009.At 59 sampling sites,a total of 23 benthic macroinvertebrate species were identified,among which,6 species were of annelids,occupying 26.1% of the total,and 8 and 9 species were of arthropods and mollusks,occupying 34.8% and 39.1% of the total,respectively.The dominant species varied greatly with the habitats,but Limnodrilus hoffmeisteri,Branchiura sowerbyi,and Bellamya aeruginosa were the three dominant taxa.The integrated biological pollution index assessment revealed that the waters in the watershed were polluted in different degrees,and the pollution status was in the order of Nanfei River Baishishan River Paihe River Chaohu Lake Zhegao River Hangbu River Yuxi River Fengle River,which was basically in agreement with the water quality index assessment.