白洋淀流域氮、磷、COD负荷估算及来源解析

基于DEM数据,运用GIS工具划分子流域,并提取土地利用和土壤类型等空间相关资料,通过文献调研和区域情况调查获取模型参数,建立白洋淀流域氮、磷、COD污染负荷模型,并进行污染源解析.结果表明:流域氮负荷为31815.47t/a,主要来自种植和土壤侵蚀,贡献率分别为26.52%和21.03%;磷负荷为3873.33t/a,主要来自土壤侵蚀和种植,贡献率分别为30.78%和25.80%;流域COD负荷为110728.52t/a,主要来自畜禽养殖和城镇污水,贡献率分别为43.47%和23.53%.总体分析表明,种植、畜禽养殖、土壤侵蚀和城镇污水是影响白洋淀流域氮、磷、COD污染物的主要来源,需优先施以管控.

Load estimation and source apportionment of nitrogen,phosphorus and COD in the basin of Lake Baiyang

The study estimates the pollution loads of nitrogen, phosphorus and COD from various point and non-point sources in the basin of Lake Baiyang using several tools including export coefficients model, PLOAD model and revise universal soil loss equation. The model parameters were collected from literature and by field surveys, and the sub-watershed, soil types and land use types were extracted based on the Digital Elevation Model (DEM) data using GIS tool. Results showed that the nitrogen load in the area was 31815.47t/a, and were mainly sourced from the agricultural field runoff (26.52%) and soil erosion (21.03%). Similarly, the soil erosion and agricultural field runoff were identified as the dominators for phosphorus load (3873.33t/a), with the contribution ratios of 30.78% and 25.80%, respectively. While for COD (110728.52t/a), livestock discharges (43.47%) and municipal domestic sewage (23.53%) were the main contributors. Overall, our analysis suggested the agricultural field runoff, livestock discharges, soil erosion and municipal domestic sewage were the main sources of nitrogen, phosphorus and COD in the basin of Lake Baiyang and should be addressed in future.