Water pollutants refer to substances that can change the physical and chemical properties of the water body, cause the water body to deteriorate, and affect the changes in the biological community structure or biological community composition, resulting in the deterioration of water quality. Also known as water pollutants.

There are many kinds of pollutants affecting water bodies, which can be roughly divided into physical, chemical, biological and other aspects. The physical aspect includes pollutants such as heat and radioactive substances; the chemical aspect mainly refers to various chemical substances discharged into the water body, including inorganic non-toxic substances (acids, alkalis, inorganic salts, etc.), inorganic toxic substances (heavy metals, cyanide, fluorine, etc.) Chemicals, etc.), oxygen-consuming organics and organic toxic substances (phenolic compounds, organic pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, detergents, etc.); biological aspects mainly include bacteria, viruses, protozoa, parasitic worms in sewage discharge and algae.