Production caused by human activities, water body pollution. Industrial water pollution is the most serious cause. If industrial wastewater containing pollutants（污染物质） it more complex components（复杂组成）, not only in water purification（水的净化） difficult, but also more difficult to deal with. Industrial wastewater, industrial pollution is the most important cause of water pollution. It accounted for the bulk of industrial emissions of pollutants. Pollutants in the industrial wastewater plant variety and diversity（多种多样） because, even similar factories, production processes, they do not contain the quality and quantity（质量和数量） of pollutants. In addition to（除此之外） the industrial wastewater discharged（排放） directly into water bodies from pollution, solid waste and emissions will pollution to the water body.

First of all, agricultural pollution is due to land reclamation projects farming land surface or loose in the soil and topography, rainfall is not stable, a natural water flows, increased water suspended objects. Another important reason is that in recent years, pesticides（杀虫剂）, fertilizers（肥料） usage growing, and the use of pesticides and chemical fertilizers or absorb only a small amount, the vast majority of the remaining residue in the soil and floating in the atmosphere, through rain, through the dirt surface runoff into surface water. Urban pollution to the water body pollution mainly sewage, it is the daily life of a sewage cooks, including the kitchen, wash room, bathroom and toilet discharge of sewage. Urban areas of the world only a year from industrial waste water and living up to 500 kilometers on, and each several times and even a few drops of sewage pollution will be 10 times the water body.