不同水期秦淮河流域水污染的分布特征及来源解析

Distribution Characteristics and Source Apportionment of Water Pollution in Different Water Periods of Qinhuai River Catchment

探索流域水环境现状、问题与污染来源是水环境质量改善和保护的前提,对生态文明建设具有重要意义。基于2015~2019年秦淮河流域29个监测站点的11个水质指标的实测数据,使用内梅罗污染指数法和正定矩阵因子分析模型对不同水期的流域水体进行水质等级、污染来源及其贡献率的解析。结果表明:氮素污染和有机污染是秦淮河流域最主要的污染类型,其中TN污染特别严重;年际变化上,2015~2019年水质呈现转好趋势,年内非汛期的水质要劣于汛期水质;汛期与非汛期的污染分布存在空间差异性,但高污染区主要集中在秦淮河下游、江宁大学城内;PMF模型结果显示汛期与非汛期的污染物来源与贡献率是存在差异的,城乡生活污水和市政废水、非点源污染、工业废水等人为源是造成秦淮河流域水体污染的主要原因,且汛期的非点源污染比非汛期贡献较多的氮磷污染物,而非汛期的工业废水比汛期贡献较多的营养盐污染。因此,在制订流域水环境保护和治理对策时应考虑区域污染的季节差异性和特征,研究结果可为秦淮河流域水环境管理和控制提供科学依据和基础。

Exploring water quality status,water problems and pollution sources in the Qinhuai River catchment is the basis for the improvement and protection of water environment,which is of great significance to constructing ecological civilization.Water quality parameters at 29 sites were investigated from January 2015 to December 2019 in the Qinhuai River catchment,Nanjing,China.The Nemeiro pollution index method and positive matrix factorization(PMF)were used to determine the water quality status and pollution sources.The results showed that nitrogen pollution and organic pollution were the most important types of pollution in the Qinhuai River Basin,of which TN pollution was the most deteriorated one.A improving trend of water quality was observed at the interannual scale,while the water quality in the non-flood season was worse than that in the flood season on the seasonal scale.Water quality parameters displayed different spatial distribution patterns during flood season and non-flood season,and the high-polluted areas were mainly concentrated in the lower reaches of the Qinhuai River and Jiangnang University Town.The results of PMF indicated that the contribution rates of pollution sources displayed different temporal distribution patterns during flood season and non-flood season.Domestic sewage and business service sewage,non-point source pollution,industrial wastewater contributed largely pollution to the whole watershed.Non-point source contributed more Nitrogen and Phosphorus to the watershed in flood season than that in non-flood season,while industrial wastewater contributed more nutrient to the watershed in non-flood season than that in flood season.Therefore,relevant departments should consider the seasonal differences and characteristics of regional pollution when formulating water environmental protection and governance countermeasures.The research results can provide a scientific basis and foundation for the water environment management and control in the Qinhuai River Basin.