Pharmaceuticals in groundwater

Pharmaceuticals occur in groundwater at around 10% of the monitoring sites throughout Switzerland. Groundwater resources in unconsolidated aquifers next to rivers are the most affected. The pharmaceuticals enter rivers and streams via sewers and sewage treatment plants, and finally infiltrate into groundwater.

According to the Waters Protection Ordinance (WPO), groundwater should generally contain no persistent synthetic substances. Primarily detected in groundwater are pharmaceuticals and radio-opaque substances used in human medicine. However, the concentrations are usually low, in most cases below 0.1 micrograms per litre (μg/l).

ABW_Arzneimittel_2019_Karte_Internet_EN
Pharmaceuticals in groundwater (2019), treated wastewater in watercourses and dense settlement. Maximum value at each monitoring site.
© FOEN

The four active substances most frequently detected in groundwater are the antibiotic sulfamethoxazole, the antiepileptic carbamazepine and the radio-opaque substances amidotrizoic acid and iopamidol. Pharmaceuticals are mainly detected at monitoring sites situated in catchment areas where watercourses charged with wastewater infiltrate into groundwater.

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Last modification 08.02.2021

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