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.
In 2013 the concentrations of pesticide active substances exceeded the limit of 0.1 μg/l specified in the Waters Protection Ordinance (WPO) at 2% of the NAQUA monitoring sites. Pesticide degradation products, for which no limit value is specified in the WPO, were detected at 21% of the monitoring sites in concentrations exceeding 0.1 μg/l. Traces of pesticide active substances and pesticide degradation products were found in the groundwater at a total of 57% of the groundwater monitoring sites.
Desphenyl-chloridazon and methyl-desphenyl-chloridazon were the substances recorded most frequently in concentrations exceeding 0.1 μg/l. Both of these substances have only been analysed as part of the National Groundwater Monitoring NAQUA since 2010 and arise as degradation products of the pesticide chloridazon, which is authorised exclusively for use in the cultivation of beets.
The pollution of groundwater with pesticide residues was greatest in agricultural areas. Concentrations of pesticide residues in excess of 0.1 μg/l were recorded at 70% of the groundwater monitoring sites in 2013.
The limit value for pesticide active substances specified by the Waters Protection Ordinance was exceeded most frequently in settlement areas. In 2013, the concentration of pesticide active substances was over 0.1 μg/l at 7% of monitoring sites in settlement areas and at 5% of monitoring sites in arable farming areas.
Pesticide concentrations in groundwater in 2013 as a function of main land use. Maximum value per monitoring site. The limit value of 0.1 μg/l specified in the WPO only applies to pesticide active substances.
Monitoring von PSM-Rückständen im Grundwasser (PDF, 7 MB, 30.06.2017)Zahlen und Fakten der Nationalen Grundwasser-Beobachtung NAQUA. Artikel in "Aqua & Gas" Nr. 6/2017.
Arzneimittel und Pestizide im Grundwasser (PDF, 3 MB, 24.02.2009)gwa 2007/3: 187-196 (german, french)
Last modification 29.08.2018