对大型盆地的有效管理需要查明主要指标超标和城市风险因素的时空驱动因素,为流域管理员提供重要的见解。然而,长江流域内多种污染物的综合检测仍然很少。在这里,我们介绍了长江流域周围城市群的污染清单,分析2018-2019年102个城市的水质数据。我们评估了六个关键指标的超标率:溶解氧(DO),氨氮(NH3-N),化学需氧量(COD),生化需氧量(BOD),总磷(TP),以及每个城市的高锰酸盐指数(CODMn)。采用随机森林回归和Shapley加法扩张(SHAP)分析,我们确定了影响这些关键指标的时空因素。我们的结果强调农业活动是导致所有六个指标超标的主要贡献者,从而指出它们是流域内的主要污染源。此外,森林覆盖率,畜牧业,化学和制药部门,连同降水和温度等气象要素,显著影响了各种指标的超标。此外,我们通过主成分分析划分了五个核心城市风险成分,它们是(1)人为和工业活动,(2)农业实践和森林范围,(3)气候变量,(4)牲畜饲养,(5)主要污染部门。随后根据这些风险成分对城市进行了评估和分类,在每个地区纳入政策干预和行政绩效。综合分析提倡在解决识别的风险因素方面采取定制的策略,特别是对于风险水平升高的城市。
Effective management of large basins necessitates pinpointing the spatial and temporal drivers of primary index exceedances and urban risk factors, offering crucial insights for basin administrators. Yet, comprehensive examinations of multiple pollutants within the Yangtze River Basin remain scarce. Here we introduce a pollution inventory for urban clusters surrounding the Yangtze River Basin, analyzing water quality data from 102 cities during 2018-2019. We assessed the exceedance rates for six pivotal indicators: dissolved oxygen (DO), ammonia nitrogen (NH3-N), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphorus (TP), and the permanganate index (CODMn) for each city. Employing random forest regression and SHapley Additive exPlanations (SHAP) analyses, we identified the spatiotemporal factors influencing these key indicators. Our results highlight agricultural activities as the primary contributors to the exceedance of all six indicators, thus pinpointing them as the leading pollution source in the basin. Additionally, forest coverage, livestock farming, chemical and pharmaceutical sectors, along with meteorological elements like precipitation and temperature, significantly impacted various indicators\' exceedances. Furthermore, we delineate five core urban risk components through principal component analysis, which are (1) anthropogenic and industrial activities, (2) agricultural practices and forest extent, (3) climatic variables, (4) livestock rearing, and (5) principal polluting sectors. The cities were subsequently evaluated and categorized based on these risk components, incorporating policy interventions and administrative performance within each region. The comprehensive analysis advocates for a customized strategy in addressing the discerned risk factors, especially for cities presenting elevated risk levels.