How Much Do You Know about Water Pollution?

We all know that our water is polluted. And I have a question here: do you know how the water is polluted? The chemical, physical, biological or radioactive characteristics of water are changed due to the intervention of certain substances, thereby affecting the effective use of water, endangering human health or destroying the ecological environment, and causing the deterioration of water quality.

Types of water pollutants

The pollutants discharged into the water are mainly divided into physical, chemical and biological pollutants according to their properties. In many cases, the accumulation of pollutants is integrated. The physical pollutants mainly includes solid suspended particles and radioactive materials. Solid suspended particles increase the turbidity of water, worsen the sensory properties of water, and can also adsorb pathogens such as bacteria and viruses in water. When water with high turbidity is used as a drinking water source, it will increase the difficulty of drinking water purification, affect the effect of drinking water disinfection, and thus increase the risk of the spread of water-borne infectious diseases. Radioactive substances in water are classified into natural and artificial types. Artificial radioactive material mainly comes from nuclear production waste, drainage of various medical and research units, etc. Radioactive substances enter the human body through contact or drinking water to produce external or internal radiation, which causes a variety of diseases such as tumors.

There are many types of chemical pollutants, estimated to be more than 2200. Common inorganic pollutants are chromium, mercury, lead, cadmium, arsenic, cyanide, phosphorus, nitrogen and various acids, bases, etc. The important organic pollutants are phenolic compounds, benzene compounds, halocarbons and various oils. When chemical pollutants in water exceed the allowable concentration, they can cause acute and chronic poisoning in humans through the amplification of drinking water or the food chain.

The biological pollutants mainly come from human and animal manure, followed by domestic sewage, hospital and slaughtering, tanning, biological medicine and food industry wastewater. Biological contamination of water can cause the spread of water-borne infectious diseases among people through drinking and contact. Common water-borne infectious diseases include Shigella, Salmonella typhi, pathogenic Escherichia coli, hepatitis A virus, etc.

Types of water pollution sources

Water pollution source refers to the source of pollutants that cause environmental pollution in water areas. Usually directed to sites, equipment, and installations that discharge pollutants or have a detrimental effect on the water environment. According to the different types of pollutants, they can be divided into organic, inorganic, thermal, radioactive, heavy metal, pathogens and other pollution sources and mixed pollution sources that discharge multiple pollutants at the same time. According to the spatial distribution of pollutants, they could be divided into point pollution, line pollution and surface pollution. According to the sources of pollutants, they can be divided into two categories: natural sources and anthropogenic sources. According to the mode of human activities, anthropogenic pollution sources can be divided into industrial, agricultural and domestic sources.

Classification of environmental quality standards for surface water

Surface water environmental quality standards are divided into five categories according to the environmental functions and protection objectives of surface water areas:

ClassⅠwas mainly suitable for source water and national nature reserves;

ClassⅡwas mainly used in the first-class protection area of centralized domestic drinking water surface water source, the habitat of rare aquatic organisms, the spawning ground of fish and shrimp, and the bait ground of young and juvenile fish;  

Class Ⅲ is mainly suitable for secondary protection areas of centralized surface drinking water sources, fish and shrimp overwintering grounds, migration channels, aquaculture areas and other fishery waters and swimming areas;  

Class Ⅳ is mainly used in general industrial water areas and recreational water areas where human body is not directly contacted;

Class Ⅴ is mainly suitable for agricultural water areas and general landscape water areas.

Pollutants that cause water pollution

(1) Industrial wastewater discharged without treatment.

(2) Domestic sewage discharged without treatment.

(3) Farmland sewage caused by massive use of chemical fertilizers, pesticides and herbicides.

(4) Industrial wastes and household wastes piled up by the river.

(5) deforestation and soil erosion.

(6) Mine sewage is generated due to excessive mining.

Water pollution hazards

The increasing water pollution has posed a major threat to human survival and security, and has become a major obstacle to human health, economic and social sustainable development. Water pollution affects people's life, destroys the ecology and directly endangers people's health. We hope everyone can get involved in protecting water...