抚仙湖代村河流域磷矿开采迹地磷入湖负荷量调查研究

Investigation and Study on the Burden of Phosphorus Loading from Phosphate Mined Land in Lake Fuxianhu Watershed

[目的]为了研究抚仙湖流域废弃磷矿区通过地表径流输移进入湖泊的磷污染负荷量。[方法]对废弃磷矿所处的代村河小流域布设监控点,进行废弃磷矿来源污染物通量周年观测和降雨径流过程加密观测,建立了代村河小流域磷矿污染物流失量、地表径流量与日降雨量关系式。[结果]估算得到磷矿废弃地产生的污染物通过代村河小流域输移总磷和磷酸盐分别为5.6和3.47 t/a;周年观测结果表明废弃磷矿产生的污染物主要通过降雨淋溶形成的地表径流向外界传输,降雨期间入湖河流水质TP浓度是非雨期间的20～80倍。[结论]废弃磷矿流失的磷是抚仙湖持久性磷污染源,必须对废弃磷矿开采区实施生态修复,减少磷释放及入湖负荷量,遏制湖泊富营养化进程。

[Objective] In order to reveal the burden of phosphorus loading from phosphate mined land into Lake Fuxianhu.[Method] Annual investigation was based on semimonthly sampling conducted at five stations in Stream Daicunhe into which runoffs from phosphate mined land load.The samples were conducted daily during rainfall runoff process.As a result,the prediction model for phosphorus loading was established among leaching phosphorus concentration,stream flow,and daily rainfall capacity.[Result] The amount of total phosphorus and dissolved phosphorus loading from phosphate mined lands into Stream Daicunhe were 5.6 and 3.47 t/a,respectively.Runoff from phosphate mined land during rainfall played primary role to transport leaching pollutant into aquatic environment.Annual investigation showed that total phosphorus loading in rainfall season was 20-80 times higher than that in dry season.[Conclusion] Phosphorus loading from phosphate mined lands is a long-term pollutant source for Lake Fuxianhu.To prohibit eutrophication process of Lake Fuxianhu,ecological restore must be performed in phosphate mined land in Lake Fuxianhu Watershed to reduce external phosphorus loading.