Pollution of the world's rivers

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Pollution of the world's rivers

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.

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 layers of soil 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.

Pharmaceutical pollution of the world's rivers, a study published on the Proceedings of the National Academy of Sciences of the United States of America, makes an interesting retrospective: "Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans.

While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective.

Furthermore, comparison of the existing data, generated for different studies / regions / continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world's rivers, representing the environmental influence of 471.4 million people across 137 geographic regions.

Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in su b-Saharan Africa, south Asia, and South America.

The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored.

Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals."