Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
Environ Sci Pollut Res Int. 2017 Dec;24(35):27201-27214. doi: 10.1007/s11356-017-0322-6. Epub 2017 Sep 30.
China is undergoing a rapid transition from a rural to an urban society. This societal change is a consequence of a national drive toward economic prosperity. However, accelerated urban development resulting from rapid population migration from rural to urban lands has led to high levels of untreated sewage entering aquatic ecosystems directly. Consequently, many of these regions have been identified as hot spots of riverine nitrogen (N) pollution because of the increasing level of urban point-source discharge. In order to address this concern, we assessed effects of urban development on ammonia-nitrogen (AN) loads using a panel data regression model. The model, expressed as an exponential function of anthropogenic N inputs multiplied by a power function of streamflow, was applied to 20 subwatersheds of the Huai River Basin for the years 2003-2010. The results indicated that this model can account for 81% of the variation in annual AN fluxes over space and time. Application of this model to three scenarios of urban development and sewage treatment (termed urbanization priority, sustainable development, and environmental priority) suggests that future N pollution will inevitably deteriorate if current urban environmental management and investment are not significantly improved. Stronger support for environmental management is very critical to alleviate N pollution and improve water quality. More effort should focus on improving sewage treatment and the N removal rate of the current sewage system in light of the increasing degree of urbanization.
中国正经历着从农村到城市社会的快速转型。这种社会变革是国家经济繁荣的必然结果。然而，由于大量农村人口向城市迁移，导致城市发展迅速，未经处理的污水直接进入水生态系统，从而导致许多地区成为河流氮污染的热点地区，因为城市点源排放的水平不断增加。为了解决这个问题，我们使用面板数据回归模型评估了城市发展对氨氮（AN）负荷的影响。该模型表示为人为氮输入乘以流量的幂函数的指数函数，适用于 2003-2010 年的淮河流域 20 个子流域。结果表明，该模型可以解释空间和时间上年度 AN 通量变化的 81%。将该模型应用于城市发展和污水处理的三个方案（称为城市化优先、可持续发展和环境优先）表明，如果当前的城市环境管理和投资没有显著改善，未来的氮污染将不可避免地恶化。加强环境管理对于缓解氮污染和改善水质至关重要。应根据城市化程度的提高，加大对污水处理和现有污水处理系统脱氮率的改进力度。
