Research on nutrient pollution load in Lake Taihu, China

The eutrophication of Lake Taihu is the joint result of internal and external pollution. Research on the sources and flux loads of total nitrogen (TN) and total phosphorus (TP) has great significance for the control and management of the eutrophication issues facing Lake Taihu. We used hydrologic and water quality surveys of the surrounding rivers, precipitation investigations, and an experimental simulation of suspended sediment to analyze the sources of TN and TP to Lake Taihu and to estimate the flux loads of TN and TP. Our results indicate that (1) surrounding rivers, atmospheric deposition, and sediment suspension were the three main sources of TN and TP, with annual flux loads of 29.6 thousand t and 2.8 thousand t, respectively; (2) for the flux load of TN, influxes from surrounding rivers accounted for 61.1%, while atmospheric deposition contributed 23.5%, with both of these sources varying seasonally. Total nitrogen released from sediments contributed 15.4% of the TN load of Lake Taihu; (3) for TP flux load, surrounding rivers accounted for 42.8% and also showed seasonal variation. Atmospheric deposition and sediment release accounted for 17.9 and 39.3% with no significant seasonal variation. This article quantitatively analyzed the sources and loads of TN and TP and provided a basis for pollution control in Lake Taihu.