The world’s water resources are increasingly polluted •


While water availability is recognized as an important and current issue that threatens people’s livelihoods and health in many regions, the same is not true for water quality. The World Bank has called water pollution an “invisible crisis” and pointed out that because water quality is often hard to detect and imperceptible to the human eye, it is under-monitored around the world.

With increasing human population, economic and agricultural development and climate change, water quality is increasingly under pressure. Yet clean water is vital for our societal needs – such as public health, energy generation and agricultural production – and for protecting the health of ecosystems. The United Nations Sustainable Development Goal (SDG) 6.3 recognizes the role of poorly managed wastewater in this crisis and calls on countries to halve the amount of untreated wastewater discharged into the environment by 2030.

The authors of a new study published in the journal Nature Communications Earth and Environment, have now developed a comprehensive new water quality model to map water problem hotspots, as well as to help understand what the water quality consequences of achieving SDG 6.3 would be. water in the world. In this high-resolution model, they consider the current and future quality of surface water in terms of salinity, levels of organic pollution and its pathogen load, as indicated by the abundance of faecal coliforms.

“We hope our model will help fill the gaps in water quality knowledge, especially in areas of the world where we lack observations,” said study lead author Edward Jones. , from the Department of Physical Geography, Utrecht UniversityNetherlands.

In addition to identifying hotspots of water quality problems, the model can help attribute the source of pollution to particular sectors. “For example, large-scale irrigation systems for agriculture lead to salinity issues in northern India, while industrial processes are more responsible in eastern China. Conversely, the domestic and livestock sectors drive organic and pathogenic pollution around the world,” Jones said.

The model predicted that while achieving SDG 6.3 would reduce water pollution to some extent, it would be insufficient to improve ambient water quality below key concentration thresholds in several regions of the world. . This would be particularly true in parts of the developing world where reductions in pollution loads are locally effective but transmission of pollution from upstream areas still results in water quality problems downstream.

“Our simulations show that for much of the year, water quality in several regions would still exceed critical thresholds for human uses and ecosystem health. This is especially the case for developing countries, especially in sub-Saharan Africa and South Asia,” Jones explained. These results highlight that while the SDG target would lead to improved water quality, it will not necessarily be sufficient and will not achieve the overarching goal of clean water for all.

Poor water quality can affect humans in different ways, the authors say. Organic and pathogenic pollution pose risks to human health, rising salinity levels threaten agricultural productivity, and rising water temperatures can disrupt thermal power plants that rely on surface water resources for cooling . In addition, all these pollutants can harm the aquatic environment and threaten ecosystems.

“Even achieving the current SDG target will pose serious economic challenges, as expanding wastewater treatment can be an expensive process,” Jones warned. “Yet the cost disadvantages of inadequate water quality for sectoral uses must also be considered. Ultimately, however, we must also reduce our pollutant emissions and develop new approaches to wastewater management. »

“As such, with this document, we hope to highlight the water quality issues we face and put these issues firmly back on the political agenda.”

Image credit: Izzet Cakalli

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By Alison Bosman, Personal editor


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