According to the environmental functions and protection objectives of surface water waters, they are divided into five categories according to the level of functions
Class Mainly applicable to source water, national nature reserves;
It is mainly suitable for centralized domestic drinking water surface water source first-class protection area, rare aquatic organism habitat, fish and shrimp spawning.
field, feeding ground for juvenile fish, etc.;
It is mainly suitable for fishery waters and swimming areas such as centralized domestic drinking water surface water source secondary protection areas, fish and shrimp wintering grounds, migratory channels, aquaculture areas, etc.
It is mainly suitable for general industrial water areas and recreational water areas that are not in direct contact with the human body
Category: Mainly applicable to agricultural water areas and general landscape requirements of waters.
Corresponding to the above-mentioned five types of surface water functions, the standard values of the basic items of surface water environmental quality standards are divided into five categories, and the standard values of the corresponding categories are implemented for different functional categories. The standard value of the high water function category is stricter than the low standard value of the water function category. Where there are multiple types of functions in the same water area, the standard value corresponding to the highest functional category shall be implemented. The realization of water function and the achievement of functional category standards have the same meaning.
The standard limits of the basic items of the surface water environmental quality standard are shown in the table (unit: mg l).
The standard limits of the centralized drinking water surface water source supplement project are shown in the table (unit: mg L).
The standard limits of specific items in the surface water sources of centralized domestic drinking water are shown in the table (unit: mg L).