基于阶段输出系数模型的农业非点源污染负荷估算与评价——以四川省为例

Estimation and evaluation of agricultural non-point source pollution load by stage export coefficient model: A case study in Sichuan Province

传统的农业非点源污染负荷输出系数模型无法实现农业非点源污染阶段负荷估算。本研究综合考虑农业用地、畜禽养殖和农村生活,从产生、流失、入河3阶段分别建立了农业非点源污染负荷估算模型,并以四川省为例,估算了2012年农业非点源TN(总氮)、TP(总磷)3个阶段的污染负荷量,分析了其主要来源及污染区域。结果显示,产生阶段中农业用地是主要污染源,遂宁、巴中、雅安和德阳产生负荷强度较高。流失和入河阶段中畜禽养殖成为主要污染源,阿坝流失负荷强度最大,遂宁水质受农业非点源污染影响最严重。研究表明,阶段输出系数模型能简便可靠地实现农业非点源污染阶段负荷估算。该研究可为农业非点源污染的源头控制、迁移过程控制和受纳水体修复提供支撑。

The traditional export coefficient model for agricultural non-point source pollution（ ANSP） load estimation can not calculate the ANSP load in different stages. Based on the export coefficient model,the stage load estimation model of ANSP was established from stages of generation,discharge and export,respectively. In the stage model,the source of ANSP was divided into agriculture land,livestock and poultry breeding and rural living. Subsequently,Sichuan Province was taken as a case study area,and the total nitrogen（ TN） and total phosphorous（ TP） loads in each stage in 2012 was calculated by the stage model. According to the stage loads of TN and TP,the main pollution source and main polluted districts were analyzed in each ANSP formation stage. It was shown that agriculture land was the main pollution source in generation stage,while livestock and poultry breeding were the main sources of ANSP in both discharge and export stages. Moreover,main polluted areas with high pollution generation load intensity of ANSP were found,including Suining,Bazhong,Ya＇an and Deyang. A＇ba was the area where the biggest discharge load in per farmland area was found,and Suining was the region where the surface water was polluted the mostseriously by ANSP in whole Sichuan Province. In conclusion,the stage load estimation model could calculate and assess the stage load of ANSP simply and effectively,and the present study could provide theoretical support for the control of ANSP.