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, up to humans, harming the ecosystem and water reserves for drinking use.
There are two main ways through which pollutants reach water: directly or indirectly. Direct pollution occurs when polluting substances are poured directly into watercourses without any purification treatment. The indirect route, on the other hand, takes place when the pollutants arrive in watercourses through the air or soil.
In natural conditions, water is able to purify itself thanks to the filtration action carried out by the layers of soil in which it permeates and to the presence of microorganisms which, with the right amount of dissolved oxygen, aerobically decompose the substances into non-toxic compounds.
pollutants. If the oxygen dissolved in the water is not sufficient to oxidize all the polluting substances present, anaerobic conditions are created, with the formation of methane, ammonia, phosphine, hydrogen sulphide, which make all forms of life in the water disappear.
An adequate presence of dissolved oxygen is therefore essential for the life of aquatic organisms. Dry Climate Aggravates Riverine Nitrogen Pollution in Australia by Water Volume Reduction, study published on the Environmental science & technology, explained: "Freshwater is a scarce resource, and maintaining water quality is of great importance in dryland Australia.
How water quality is affected by the dry climate and socio-economic influences in Australia remains widely unknown. Here, we find that agriculture activity dominates reactive nitrogen ( Nr) emissions to water bodies Such emissions not only contribute to deteriorating water quality in Southeastern Australia but also harm marine ecosystems, including the Great Barrier Reef, a World Natural Heritage site A dry and warm climate reduces the share of Nr emitted directly to however, it increases the Nr concentration in surface water due to reduced water volume, leading to a 3-fold higher water Nr concentration compared to major rivers globally, e.g., in the US or China would increase the total Nr emitted to surface water by at least 43% by 2050, while effective mitigation measures could reduce N runoff by about 27%.
cultural management strategies should be considered to reduce future environmental pressures due to N runoff in Australia."