Abstract:

There are plenty of small lakes distributed in Hanyang District, and these lakes are almost belonging to type V of water quality due to the inputting of industrial and domestic waste water.Macrobenthos has been widely used to monitor the organic pollution.To detect the extent and distribution of pollution in these lakes (Sanjiao Lake,Moshui Lake,Longyang Lake,Yue Lake,Houguan Lake),this study made investigations of macrobenthos community and researches on their indication to lake environment during 2002~2005.Besides of Houguan Lake with one species of mollusca, the other lakes were only inhabited by pollutanttolerant species,i.e.tubificids (e.g.〖WTBX〗Limnodrilus hoffmeisteri, Branchiura sowerbyi) and chironomids (Tanypus sp,Propsilocerus akamusi,Chironomus plumosus).Statistical analyses revealed that densities of tubificids and chironomids were significantly positively correlated with total nitrogen, phosphorus and Chla (p<005). The correlation coefficients (R²) of regression between tubificid densities and nutrients (TN,TP) were higher than that of chironomids, which indicated that the tubificid densities were more reliable for predicting trophic level than chironomid.The result of water quality bioassessment was almost consistent with the physicalchemical evaluation,i.e.Moshui Lake and Longyang Lake were severely polluted,Yue Lake and Sanjiao Lake were moderately polluted and Houguan Lake was slightly polluted. Not any macrobenthos was collected in the eastern phenolpolluted area of Longyang Lake,which validated the monitoring role of macrobenthos in the longterm effect of pollution. Furthermore,this study utilize〖JP2〗d the spatial pattern of tubificid to indicate the pollution pattern of these lakes.On the basis of environmental analyses,this study validated the reliable role of tubificid in monitoring organic pollution