广东省农业面源污染现状及变化的多尺度评价

    Multi-scale Assessment of Agricultural Non-point Source Pollution Loadings and Its Changing Characteristics in Guangdong Province

    • 摘要: 第二次全国污染源普查显示,农业面源污染已成为广东省水环境恶化的主要原因之一,理清全省面源污染状况对水污染防治和乡村振兴建设具有重要意义。采用改进输出系数法分析2009—2019年广东省农业面源污染年负荷量及其时空变化特征,考虑施肥、降水、畜禽和水产养殖各月差异,评估全省农业面源污染季度和月污染负荷;采用单位面积负荷系数法评价农业面源污染对环境的影响程度,并探讨农业面源污染主要来源。结果表明:(1)2009—2019年广东省总氮负荷呈下降趋势,总磷负荷呈上升趋势,春夏两季是一年中污染排放的高峰季度,4—10月总氮和总磷负荷分别占全年负荷的68.8%和67.2%。(2)全省76.2%的地级市总氮负荷呈下降趋势,61.9%的地级市总磷负荷呈上升趋势。相比于2009年,2019年71.4%的地级市总氮排放对环境威胁程度降低,52.4%的地级市总磷排放对环境威胁程度增强。(3)粤西地区农业总氮、总磷负荷及对环境的影响均较珠三角、粤北和粤东地区更为严重。(4)各污染源对氮磷污染负荷量的贡献率从大到小依次为畜禽养殖业、种植业和水产养殖业。研究结果为广东省农业面源污染现状及变化的评价提供了参考,对全省农业面源污染防控及建设美丽乡村具有重要意义。

       

      Abstract: The second national pollution source survey show that agricultural non-point source pollution (ANP) has become one of the main causes of water environment deterioration in Guangdong Province. Therefore, it is important to clarify the ANP status in the province for the prevention and control of water pollution and for rural revitalization. The improved export coefficient method was used to analyze the annual ANP loads and its spatial and temporal variation characteristics in Guangdong Province from 2009 to 2019. On this basis, the seasonal and monthly pollution loads of ANP in the province were evaluated with consideration of monthly differences in fertilizer application, precipitation, livestock and aquaculture. The impact of ANP on the water environment was evaluated by unit area load coefficient method, and the main sources of ANP were explored. The results indicate that: (1) from 2009 to 2019, the total nitrogen load in Guangdong Province showed a decreasing trend and the total phosphorus load showed a rising trend with spring and summer being the peak seasons of pollution discharge in a year, and the total nitrogen and phosphorus discharge from April to October accounting for 68.8% and 67.2% of the annual load, respectively. (2) The total nitrogen load trended decreasing in 76.2% of the cities and the total phosphorus load trended increasing in 61.9% of the cities, and compared to 2009, the total nitrogen load in 71.4% of the cities decreased the threat to the environment and the total phosphorus load in 52.4% of the cities enhanced the threat to the environment in 2019. (3) In general, the environmental damage caused by agricultural nitrogen and phosphorus loads in western Guangdong was more serious than that in Pearl River Delta, and in northern and eastern Guangdong. (4) The contribution rate of each pollution source to nitrogen and phosphorus pollution loads from high to low is livestock and poultry breeding, crop farming and aquaculture. The evaluation results of the current situation and change characteristics of ANP in the province are of great significance to the prevention and control of ANP and the construction of beautiful countryside in the province.

       

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