摘要
China has a huge population with relatively poor freshwater resources.With the development of industry and the explosion of its urban population,a great deal of industrial waste water containing various chemicals and untreated urban sewage has been discharged into rivers and lakes and caused severe contamination of many freshwater resources.The deterioration of the aquatic environment has affected the quality of drinking water, fishery and agricultural irrigation.It is estimated that by the 21st century,there will be a shortage of freshwater resources,which arc indispensable to human life, and the future shortage of freshwater
