湖南省农业面源污染风险等级区划及防治对策

Risk level zoning and countermeasures for agricultural non-point source pollution in Hunan Province

为全面掌握湖南省农业面源污染状况,探讨农业面源污染风险等级区划及防治对策,本研究运用等标污染负荷法和GIS空间分析法,基于单位国土面积等标污染负荷和单位地表径流等标污染负荷对湖南省2018—2021年农业面源的污染源、污染物及其空间分布特征进行分析。结果表明:湖南省农业面源TN污染负荷最高,2018—2020年贡献率均在40%以上。污染负荷总体呈中部高、向四周逐渐降低的分布趋势。通过自然间断点分级法可将全省分为高、中、低风险区3个一级分区,根据污染来源,将全省划分为畜禽养殖污染型、农村生活污水污染型、农村生活污水-畜禽养殖污染型、农村生活污水-种植污染型、种植-畜禽养殖污染型、复合污染型6种污染类型,形成14个二级分区,并根据不同区划类型提出了湖南省农业面源污染的防治对策。

We explored the risk level zoning and control measures for agricultural non-point source pollution,which used the equivalent standard pollution load method and GIS spatial analysis method to fully grasp the pollution situation in Hunan Province.Based on the equivalent pollution load of land area and the pollution load per unit of surface runoff,this paper analyzed the data of the sources,types,and spatial distribution of agricultural non-point pollution sources in Hunan Province from 2018 to 2021.The results showed that the TN pollution load of agricultural non-point sources was the highest,with the contribution rate more than 40%from 2018 to 2020.The value was generally higher at the center of the province and gradually decreased in the surrounding area.The risk level of Hunan Province can be zoned into three levels,i.e.,high-risk areas,medium-risk areas,and low-risk areas,via natural discontinuity grading method.The pollution sources can be divided into six types,i.e.,livestock and poultry farming pollution type,rural domestic sewage pollution type,rural domestic sewage livestock and poultry breeding pollution type,rural domestic sewage planting pollution type,planting livestock and poultry breeding pollution type,and combined pollution type.The control measures of agricultural non-point source pollution in Hunan Province were put forward according to 14 sub-regions based on the above six source types.