近几十年太湖流域氮素来源变化及控制

Change and Control Measures of Nitrogen Sources in Taihu Lake Basin in Recent Decades

通过对太湖氮素污染来源进行分析,农业面源、工业污水、生活污水输入氮素量显著升高,20世纪60-80年代,氮素主要来自于农业面源污染,而21世纪后,仍以农业面源为主,工业污水比重显著升高,农业面源、生活污水所占比重缩小;内源污染释放受多重因素影响,但总量低于其他外源污染;大气沉降输入虽所占比重不高,输入量逐渐增加。因此,在治理氮素控制方面应该由单纯重视农业面源污染转向多种污染共同重视。应加强立法,制定适应当地生态系统、环境保护的氮排放政策,并加大实施力度;弄清点源、非点源、大气沉降等过程中氮排放的源头,面源污染方面应优化氮肥管理模式,可采用缓控释肥或按需施肥的方式,并加强过程阻断及拦截技术,以减少氮向环境的释放;对生活污水,因鼓励居民节约用水,减少生活污水排放,并深化生活污水的处理及综合利用;工业污水成分复杂,危害严重,也需重点管控,提高排放标准,加强监测,提高生产工艺,深化污水处理力度;对内源污染十分严重区域可实施清淤工程,最终应以恢复水生植物为首要任务;对大气沉降,重点做好源头控制,管理好机动车、工业生产、农业生产等源头,可有效降低排放量。

By analyzing the sources of nitrogen pollution,the amount of nitrogen input from agricultural non-point source,industrial sewage and domestic sewage increased significantly.Nitrogen mainly came from agricultural non-point source pollution from 1960s to 1980s,it was still the main pollution source after 2000.The proportion of agricultural non-point source,and domestic sewage decreased.The release of endogenous pollution is affected by multiple factors,but the total amount is lower than exogenous pollution sources.Although the proportion of atmospheric deposition is not important,the amount of nitrogen deposition increased gradually.Therefore,the focus should be changed from non-point source pollution to a multiple pollution,legislation should be strengthened,the policies for nitrogen emission should be adapted to local ecosystem and environmental protection and strengthen the implementation.The point source,non-point source and atmospheric deposition should be clarified.Nitrogen fertilizer should be optimized in non-point source pollution,the sustained-release fertilizer or on-demand fertilization can be adopted,and process interdiction and interception should be strengthened in order to reduce the release of nitrogen.The residents should be encouraged to water conservation,reduce the discharge of domestic sewage,and the treatment and comprehensive utilization of domestic sewage should be enhanced.Industrial sewage has complex components and serious hazards.It also needs to focus on management and control,improve discharge standard,strengthen monitoring,improve production technology and strengthen sewage treatment.Dredging projects can be implemented in serious endogenous pollution,and the restoration of aquatic plants should be the primary task ultimately.For atmospheric deposition,the focus should be on source control,and the management of motor vehicles,industrial production,agricultural production and other sources can effectively reduce emissions.