Water quality in watercourses

Water quality in watercourses has improved significantly since the 1970s in terms of nutrient pollution. Micropollutant contamination is the new and biggest challenge at this time.

Bathing water quality

Thanks to various protective measures and major advances in wastewater treatment in recent decades, water quality in Swiss rivers and lakes is now very high and virtually all are clean enough to swim in.

Biology

A large proportion of the waterbodies in the Swiss Plateau can only fulfil their role as habitats for animals and plants to a limited extent, as a biological assessment of streams and small rivers shows. The species composition in large rivers is also strongly impacted by human activity and invasive alien species. The Red Lists give a clear indication of how the quality of waterbodies is severely compromised; over 50 per cent of all species living in and around them are endangered or already extinct.

Micropollutants

Many micropollutants can be detected in Swiss watercourses. Pesticides exceed their ecotoxicological limits primarily in streams and small watercourses, whereas in large rivers there are excessive levels of some medicinal products. In the affected watercourses in densely populated and intensively farmed regions, sensitive animal and plant species are exposed to a high risk of harm from these substances.

Nutrients in watercourses

Nutrient concentrations in watercourses are highest where many nutrients are discharged via wastewater treatment plants (WWTPs) and from agriculture. This is particularly the case on the Swiss Plateau and on the valley floors. Nutrients enter lakes and the sea via rivers. High concentrations of nitrates in Swiss water contribute to their overfertilisation from nitrogen.

Heavy metals

Heavy metal pollution in Swiss watercourses is on a downward trend.

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Last modification 23.08.2022

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