types of water pollution
What are the types of water pollutants? According to different water sources, water pollutants mainly include the following types.
organic pollution
Organic pollution is the pollution of water bodies caused by the large discharge of domestic sewage and industrial wastewater containing organic matter. When organic matter is decomposed by microorganisms in water, it consumes dissolved oxygen in the water, leading to oxygen deficiency and the production of gases such as hydrogen sulfide and ammonia, leading to deterioration of water quality. Therefore, organic pollution is an important form of pollution in water bodies, which has a significant impact on the normal life of aquatic organisms and the deterioration of water quality.
thermal pollution
Thermal pollution refers to the increase in water temperature caused by the discharge of industrial thermal cooling wastewater into the water body. Thermal pollution mainly comes from the cooling circulating water throughout various industrial production processes. If effective measures are not taken and immediately discharged into the water, it is likely to cause temperature rise, decrease in dissolved oxygen content, and increase in toxic side effects of some toxic substances present in the water, thereby seriously endangering the growth and development of fish species and aquatic organisms. Thermal power plants, metal smelters, petrochemical plants, and other plants often discharge high-temperature wastewater. An increase in water temperature can reduce the concentration of dissolved oxygen in the water, accelerate the rate of biological oxygen consumption, accelerate algae growth, and accelerate chemical reactions in the water, ultimately leading to a decrease in the self purification capacity of the water body.
Plant nutrients such as nitrogen and phosphorus
Water pollutants include plant nutrients such as nitrogen and phosphorus, which can enter slow-moving water bodies such as lakes, reservoirs, and bays, promoting the activity of various aquatic organisms, stimulating abnormal algae growth, and causing a series of serious consequences. In addition, nitrate poses great harm to human health. Although it is non-toxic, nitrate may be reduced to nitrite in the human stomach. Nitrite can react with secondary amines to produce nitrosamines, which are the so-called three carcinogens, mutagens, and teratogens. Therefore, the national regulations stipulate that the nitrate content in drinking water shall not exceed 10mg/L.
oil pollution
Oil pollution refers to the discharge of a large amount of oil pollution in water bodies, resulting in water pollution. Oil pollutants mainly include crude oil, tanker transportation, wastewater from the refining industry, and freshwater oil fields. These substances form a thin film in water, blocking the dissolution of oxygen in the air, leading to a decrease in oxygen concentration in the water, which in turn leads to water quality deterioration and poses a threat to the ecological environment of aquatic organisms. In addition, oil pollution can also cause a decrease in aquatic production, contaminate water and aquatic food, and pose a threat to the health of humans and other animals.
Radioactive contamination
Radioactive material pollution refers to the development trend of nuclear energy industry production, which leads to the use of radioactive materials in industries such as medicine, industrial production, and scientific research, resulting in certain levels of radioactive material pollution. Radioactive substances mainly come from the nuclear industry and industrial or civilian sectors that use them. They can be transferred from water or soil to organisms, vegetables, or other foods, and are concentrated and enriched into the human body. The radiation released by radioactive substances can damage the health of individuals, and the most common radiation disease is blood cancer, also known as leukemia.
Heavy metal toxic substances
The toxic substances of heavy metals mainly include lead, chromium, cadmium, mercury, copper, etc. These heavy metals have significant and biological toxicity, and cannot be degraded by microorganisms. They can only undergo various forms of mutual transformation, dispersion, and enrichment processes. The characteristic of heavy metal pollution is that, in addition to being carried away by suspended solids, it will accumulate in the sediment near the sewage outlet due to adsorption and sedimentation, becoming a long-term secondary pollution source. Various inorganic and organic ligands in water can form complexes or chelates with them, resulting in greater water solubility of heavy metals and the possibility of re release of heavy metals that have already entered the sediment. The valence states of heavy metals vary, and their activity and toxicity vary.
Pathogenic microbial contamination
Water pollutants include organic matter and pathogens, among which pathogen pollution refers to domestic sewage, wastewater from livestock and poultry farms, hospital sewage, etc. containing pathogens. If these sewage is improperly treated and flows into the water, it can cause the spread of various bacteria and endanger human health. In addition, pathogenic domestic sewage, hospital sewage, and industrial wastewater from slaughtering, tanning, hair washing, and biological products often contain pathogens, which can spread cholera, typhoid fever, gastritis, enteritis, dysentery, and other viral and parasitic diseases.
Inorganic pollution
The inorganic pollution in water mainly comes from the wastewater discharged by factories, such as hydrocyanic acid, potassium cyanide, sulfuric acid, nitric acid, etc. Excessive inorganic pollutants can change the pH value of water, causing microorganisms to not grow and consuming dissolved oxygen in the water, endangering freshwater organisms. In addition, inorganic pollutants also include heavy metal ions, fluoride, and nitrite. These inorganic pollutants have potential hazards to the water environment and organisms, and measures need to be taken for governance.
Acid alkali pollution
Acid and alkali pollution refers to the discharge of acid and alkali substances in water bodies, leading to changes in pH values, disrupting the natural buffering effect of water, affecting the self purification capacity of water bodies and fishery production. In severe cases, it can also corrode ships, bridges, and other aquatic buildings. Acid mainly comes from mining drainage, industrial wastewater, and acid rain, while alkali mainly comes from industrial wastewater such as alkaline papermaking, chemical fiber manufacturing, alkali making, and tanning. Acid alkali pollution is a common phenomenon in water pollution, which has an impact on normal ecosystems.
Sensory pollution
Water pollutants include substances in wastewater that cause water turbidity, foam, odor, discoloration and other phenomena, and substances in wastewater that can cause people to feel extremely unhappy, discoloration, turbidity, foam, odor and other phenomena. Sensory pollution refers to the changes in water pollution perceived by human vision, taste, smell, and other aspects, including color changes, turbidity changes, blisters, odors, etc. These water pollutants, although not seriously harmful, can cause extreme discomfort in people’s senses and are called sensory pollutants.
Solid suspended solids
Solid suspended solids refer to pollutants suspended in water, including sediment, rust, visible objects, etc. They mainly harm the drainage channels of water bodies, suffocate benthic organisms in water, destroy fish spawning grounds, and also reduce water quality, increase the difficulty and cost of purifying water. The difficult to degrade solid components in modern household waste entering water bodies can cause aquatic animals to die after ingestion. Solid suspended solids can also adsorb organic toxins, heavy metals, pesticides, etc., forming more harmful composite pollutants that sink into the bottom of the water. Over time, they form sedimentation, which can hinder water transportation or reduce reservoir capacity, increasing the burden of dredging.
Eutrophication pollution
Eutrophic pollution refers to the pollution caused by excessive nutrient content in water bodies, resulting in the proliferation of aquatic plants. The hazards of eutrophication in water bodies include the proliferation of aquatic plants, the consumption of dissolved oxygen in water, and the suffocation and death of fish. In addition, eutrophication can also cause a significant decrease in dissolved oxygen in water bodies, leading to deterioration of water quality and the death of aquatic organisms. The methods for preventing eutrophication pollution include controlling the input of exogenous nutrients, reducing the load of endogenous nutrients, and controlling the mass reproduction of green plants such as algae.