Lijiang River health assessment using a benthos index of biotic integrity for invertebrate

In order to develop a benthos index of biotic integrity(B-IBI) for benthic invertebrate and assess the water quality health of the Lijiang River basin,benthic invertebrate communities and hydrochemical variables were investigated in March 2008 at 31 sites,of which 17 were reference sites and 14 were monitoring sites.TP,TN,NH+4-N and CODMn were lower at reference sites than at monitoring sites.Forty-six candidate biological parameters were selected and calculated from the data of all sites and sequentially analyzed to develop the B-IBI.The B-IBI was composed of four biological parameters: total taxa,EPT taxa,pecentape of Heptageniidae in Ephemeroptera,and percentage of dominant taxa.It was suggested that the water quality in Lijiang River basin was healthy for B-IBI≥21,and unhealthy for BIBI21.The assessment results using B-IBI showed that most of the branches in the middle and upper reaches of the Lijiang River were healthy,and the lower reaches of the Lijiang River were unhealthy.