Groundwater quality

The quality of groundwater in Switzerland is generally good to very good. In conurbations and regions with intensive agriculture, however, groundwater can contain traces of undesirable artificial substances.

Plant protection products in groundwater

Pesticide residues, i.e. the active substances contained in pesticides and pesticide degradation products, were found in concentrations exceeding 0.1 ug/L at around 22% of the groundwater monitoring sites throughout Switzerland. In intensive arable farming areas, concentrations of pesticide residues exceed this level at around 70% of the monitoring sites.

Pharmaceuticals in groundwater

Residues of pharmaceutical products occur mainly at groundwater monitoring sites situated close to rivers. They originate from urban sewage systems, enter rivers and streams via treatment plants and finally reach groundwater by bank filtration.

Perfluorinated Chemicals in Groundwater

Residues of perfluorinated chemicals occur primarily at groundwater monitoring sites near rivers. The discharge of treated or untreated wastewater into surface waters and the subsequent infiltration of these waters into groundwater appear to be the major source of PFC in Swiss groundwaters.

Nitrate in groundwater

Nitrate is naturally present in groundwater only in low concentrations. Distinct elevated concentrations of more than 25 mg/l nitrate occur nationwide at up to 15% of the monitoring sites sampled. In areas used predominantly for arable farming, the concentrations exceeded this level at up to 60% of the monitoring sites.

Volatile organic compounds in groundwater

Volatile organic compounds (VOCs) occur in groundwater in concentrations above 1 µg/l at up to 4% of the monitoring sites sampled throughout Switzerland. In urban areas the VOC concentrations are above this level at 14% of the monitoring sites.

Further information

Last modification 29.08.2018

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