The type of water pollution can be of a chemical, physical or microbiological nature and the consequences can compromise the health of the flora and fauna involved, including humans, harming the ecosystem and water reserves for drinking purposes.
There are two main routes through which pollutants reach the water: either directly or indirectly. Direct pollution occurs when polluting substances are poured directly into water courses without any purification treatment.
The indirect route, on the other hand, occurs when pollutants arrive in watercourses via air or soil. Under natural conditions, water is able to self-purify itself thanks to the filtration action carried out by the soil layers in which it permeates and to the presence of microorganisms which, with the right amount of dissolved oxygen, aerobically decompose substances into non-toxic compounds.
pollutants. If the oxygen dissolved in the water is not sufficient to oxidize all the pollutants present, anaerobic conditions are created, with the formation of methane, ammonia, phosphine, hydrogen sulphide, which make all forms of life disappear in the water.
An adequate presence of dissolved oxygen is therefore essential for the life of aquatic organisms. The study A review of water pollution arising from agriculture and mining activities in Central Asia: Facts, causes and effects, published on the Environmental pollution, said: "Central Asia is one of many regions worldwide that face severe water shortages; nevertheless, water pollution in this region exacerbates the existing water stress and increases the risk of regional water conflicts.
In this study, we perform an extensive literature review, and the data show that water pollution in Central Asia is closely linked to human activities. Within the Asian Gold Belt, water pollution is influenced mainly by mining, and the predominant pollutants are heavy metals and radionuclides.
of inland rivers, water pollution is strongly associated with agriculture. Hence, irrigated areas are characterized by high concentrations of ammonia, nitrogen, and phosphorus. In addition, the salinities of rivers and groundwater in the middle and lower reaches of inland rivers generally increase along the flow path due to high rates of evaporation.
Soil salinization and frequent salt dust storms in the Aral Sea basin further increase the pollution of surface water bodies. Ultimately, the pollution of surface water and groundwater poses risks to human health and deteriorates the ecological environment.
To prevent further water pollution, joint monitoring of the surface water and groundwater quantity and quality throughout Central Asia must be implemented immediately."