The characteristics of phosphorus pollution in water-sendiment interface from Dianchi Lake, China

Dianchi Lake, one of the most eutrophication freshwater lakes in china, has been under severely eutrophic condition since 1970s. This study investigated the concentrations of total phosphorus (TP), soluble reactive phosphorus (SRP) in the overlying water and the interstitial water in water-sediment interface through analysis of the water samples collected from 37 sites around Dianchi Lake to obtain further understanding of recent characteristics of phosphorus pollution, and to estimate the dominant potential phosphorus sources in varied lake regions. Results showed that the mean TP and SRP contents were 0.271 mg/L, 0.039 mg/L in Waihai and 0.356 mg/L, 0.159 mg/L in Caohai from the overlying water, compared with 0.395 mg/L, 0.010 mg/L in Waihai and 1.229 mg/L and 0.790 mg/L in Caohai from the interstitial water, respectively. It was revealed that the internal phosphorus source has been the dominant phosphorus pollution sources occurred in prolonged pollutant accumulation and hyper-eutrophication Caohai section, the external and internal phosphorus sources coexist in wide open Waihai section.