非点源污染的管理及控制

Non-point Source Pollution Control and Management

非点源污染是指溶解的或固体污染物从非特定的地域，在降水和径流冲刷作用下，通过径流过程而汇入受纳水体（如河流、湖泊、水库、海湾等）引起的水体污染．主要起源于土壤侵蚀、农药与化肥的施用、农村家畜粪便与垃圾、农田污水灌溉、城镇地表径流、林区地表径流和大气干湿沉降等污染源．由于其形成过程受区域地理条件、气候条件、土壤结构、土地利用方式、植被覆盖和降水过程等多种因素影响，具有随机性大、分布范围广、形成机理模糊、潜伏性强、滞后发生和管理控制难度大的特点．非点源污染的发生，对区域生态环境和人类健康形成了严重的危害，不仅污染饮用水源，而且造成地表水的富营养化和地下水污染，破坏水生生物的生存环境，引起生物量的减少或死亡．本文在分析了非点源污染的形成、特征和危害之后，详细介绍了美国在非点源污染管理与控制方面的经验，对于我国在这方面的研究和管理具有重要的指导意义．

Compared to point source pollution,non point source pollution is more common and severe and its management is also more challenging.Non point source pollution originates from diffuse areas where some solvable or solid pollutants are produced.When these pollutants enter the waterbodies,such as lakes,river,reservoir and gulf with runoff during rainy season,water pollution or eutrophication could be induced.Normally,the soil erosion,application of chemical fertilizer and pesticide in farmland,piling of domestic animal's excrement or garbage in rural areas,surface runoff from urban areas and forest areas,irrigation with waster water in farmland and air dry wet deposit are considered as the principal sources of non point source pollution.Due to the influence of various factors,non point source pollution is characterized by random process,complex mechanism,widespread distribution,latent occurrence.Thus a practical difficulty is remained to study and control non point source pollution.Apart from sources,adverse effects and characteristics of non point source pollution were analyzed in this paper,the experiences and methods on managing and controlling non point source pollution in USA were also introduced.It will be helpful for Chinese government to make a feasible decision on this issue.