沱江流域主要污染负荷预测及时空分布特征

Forecast and Spatial Distribution of Main Pollution Loads in the Tuojiang River Basin

耦合社会-经济因子探究工业点源和生活污染源污染负荷未来变化趋势,可为优化水环境规划和管理方案提供理论依据。选取沱江流域为研究区域,采用经济增长预测法、工业点源传统统计法、人口趋势灰色模型预测法和排污系数法分别计算了2020—2025年该区域28个县(市、区)的工业GDP值,工业点源废水排放量及主要污染负荷(COD、NH_(3)-N、TN、TP),农村与城镇人口及生活污染源的主要污染负荷,并利用ArcGIS技术探究了工业点源和生活污染源主要污染负荷空间分布特征。结果表明:2020—2025年,工业GDP值总体呈逐年增加趋势,而工业废水排放量总体呈逐年减少趋势,预计到2025年,流域工业GDP值将增加至2.52×10^(12)元,而工业废水排放量将减少至0.64×10^(8)t。工业点源主要污染负荷表现为COD>NH_(3)-N>TN>TP。沱江流域总人口数与生活污染源污染负荷呈逐年增加趋势,其中城镇人口与生活污染源污染负荷呈逐年增加趋势,农村人口与生活污染源污染负荷呈逐年减少趋势,且城镇人口及生活污染源污染负荷增加量大于农村人口及生活污染源污染负荷减少量。城镇、农村生活污染源的主要污染负荷表现为COD>NH_(3)-N>TN>TP。工业点源和生活污染源主要污染负荷在空间上存在高度异质性。2025年,来自工业点源的主要污染负荷均呈上游较少,中、下游较多的特征;来自城市生活污染源的主要污染负荷均呈中、上游较多,下游较少的特征;来自农村生活污染源的主要污染负荷均呈中游较多,上、下游较少的特征。笔者提出耦合社会-经济因子预测流域污染负荷的方法可以推广到其他与社会经济指标相关联的流域工业点源、生活污染源污染负荷的预测研究中,以期为未来流域水环境管理与治理提供科学参考。

Coupling socio-economic factors to explore the future trend of pollution loads from industrial point sources and domestic pollution sources can provide a theoretical basis for optimizing planning and management schemes of water environment.Taking the Tuojiang River basin as the study site,the data of industrial GDP,discharge of industrial waste water and its pollution loads(COD,NH_(3)-N,TN,TP),populations of rural and urban and its pollution loads in 28 counties of the study site from 2020 to 2025 were separately predicted by the methods of economic growth prediction,industrial point sources statistics,the population Grey model prediction and discharge coefficient,respectively.Moreover,this study explored the spatial distribution of main pollution loads from industrial point sources and domestic non-point sources by ArcGIS analysis technologies.The results showed that:From 2020 to 2025,the industrial GDP of the Tuojiang River basin will increase year by year,while the industrial wastewater discharge will generally decrease year by year.In 2025,the industrial GDP will increase up to 252 billion yuan,but the industrial waste water discharge will decrease to 0.64×10^(8 )t.The rankings of main pollution loads from industrial point sources are as follows:COD >NH_(3)-N >TN >TP.The total population(including urban population and rural population) and the pollution loads from domestic non-point sources in Tuojiang River watershed showed obviously growing trends.The urban population and its pollution loads from domestic non-point sources will increase,while the rural population and its pollution loads from domestic non-point sources will decrease.The rankings of main pollution loads from rural and urban domestic non-point sources are the same as the rankings of main pollution loads from industrial point sources.The main pollution loads from industrial point sources and domestic non-point sources were highly spatial heterogeneity.In 2025,the lower value of main pollution loads from industrial point sources will appear in the upper reaches,and larger value will appear in the middle and lower reaches.The larger value of main pollution loads from urban domestic non-point sources will appear in the middle and upper reaches,the lower value will appear in the lower reaches.The higher value of main pollution loads from rural domestic non-point sources will appear in the middle reaches,the lower value will appear in the upper and lower reaches.The method coupled socio-economic factors proposed in this study can be promoted to study on pollution loads from industrial point sources and domestic non-point sources associated with socio-economic indicators in rivers,which can provide a scientific evidence for management on water environment in rivers.