汉江流域安康段面源污染特征分析

Analysis of Non-Point Source Pollution Characteristics of Ankang Section in the Hanjiang River Basin

分析汉江流域安康段面源污染的COD、TN、TP负荷量、负荷强度及其空间分布,评估区域污染风险,并识别区域面源污染的主要污染源和污染物,对各县市区的污染类型进行划分,以期为汉江流域安康段合理制定面源污染治理策略提供依据。结果表明:2020年汉江流域安康段面源污染的COD、TN、TP负荷量分别为65 162.49 t、24 225.20 t和1 531.17 t,等标污染负荷比分别为6.38%、71.14%和22.48%,TN是首要污染物;主要污染源按等标污染负荷比从大到小排列依次为耕地(54.70%)、畜禽养殖(28.83%)、农村生活(15.59%),首要污染源为耕地;各县市区面源污染COD、TN和TP负荷量、负荷强度和等标污染负荷比的空间分布具有很强的一致性,主要污染区域为汉滨区和旬阳市;各县市区被划分成土地利用污染主导型、畜禽养殖和土地利用污染主导型、土地利用和畜禽养殖污染主导型、混合污染型4种污染类型。因此,提出安康市可根据污染类型采取有针对性的控制措施,汉滨区和旬阳市耕地引起的面源TN污染应得到首先治理。

The COD,TN and TP loads,load intensity and spatial distribution of non-point source pollution of Ankang section in the Hanjiang River basin were analyzed,regional pollution risks were assessed,major sources and pollutants of regional non-point source pollution were identified,and pollution types in various counties,cities and districts were divided,so as to provide basis for reasonable formulation of non-point source pollution control strategies of this section.The results showed that the COD,TN and TP loads of non-point source pollution of Ankang section in the Hanjiang River basin in 2020 were 65162.49 t,24225.20 t and 1531.17 t,respectively,the corresponding equivalent standard pollution load ratios were 6.38%,71.14%and 22.48%,respectively,and TN was the primary pollutant.The main pollution sources were cultivated land(54.70%),livestock and poultry breeding(28.83%)and rural life(15.59%),and the primary pollution source was cultivated land.The spatial distribution of the COD,TN and TP loads,load intensity and equivalent standard pollution load ratios of non-point source pollution in counties,cities and districts had strong consistency,and the main pollution areas were Hanbin District and Xunyang City.Counties,cities and districts were divided into four pollution types:the land use pollution leading type,livestock and poultry breeding and land use pollution leading type,land use and livestock and poultry breeding pollution leading type and mixed pollution type.Therefore,it was suggested that targeted control measures should be taken in Ankang City according to pollution types,and non-point source TN pollution caused by cultivated land in Hanbin District and Xunyang City should be controlled first.