Requirement values

The Swiss Water Protection Ordinance (GSchV) specifies the requirements for all pesticides used in biocidal products or plant protection products. For surface waters, 19 pesticides are regulated with substance-specific, ecotoxicologically based requirements. In waters used for drinking water, these values only apply if they do not exceed the requirement of 0.1 μg/L. For all organic pesticides that are not specifically regulated, the requirement of 0.1 μg/L applies. For groundwater used for drinking water production, a requirement value of 0.1 μg/L applies to all organic pesticides. If these values are exceeded, the authorities must consider taking measures. According to the Drinking, Bathing and Showering Water Ordinance (TBDV), the general requirement value of 0.1 μg/L applies to drinking water. Pesticide degradation products (metabolites) classified as relevant to human toxicology may only be present in drinking water in concentrations below 0.1 μg/L. The total amount of all pesticides must not exceed the requirement of 0.5 μg/L.  [1]

Requirements from the approval

There are two different approval systems for pesticides, depending on their use. The approval of plant protection products is regulated in the ‘Ordinance on the Placing of Plant Protection Products on the Market’, or Plant Protection Products Ordinance (PSMV) for short. The approval of biocides is regulated in the Biocidal Products Ordinance (VBP). Under both systems, before an active substance is authorised, an assessment must be made as to whether its intended use poses a risk to humans and the environment. However, different methods are used to determine the respective requirement value for surface waters. The methodology used under the BPD to determine the predicted no-effect concentration (PNEC) is almost identical to that used to derive environmental quality criteria. The assessment values under the PSMV, on the other hand, are derived using a different methodology. The resulting RAC values (for ‘regulatory acceptable concentrations’) can, for example, accept effects on aquatic organisms if the communities can recover within a few weeks. Higher values can therefore be declared permissible than in the aquatic assessment. In addition, the plant protection product authorisation works with (predicted) peak concentrations that may occur in the aquatic environment after application. This makes it difficult to verify RAC values from the authorisation with concentrations actually measured in water bodies. This is because short-term peak concentrations are not recorded in practical water monitoring. This is very costly in terms of analysis, and it is not yet possible to measure a wide range of pesticide active substances over several months with the necessary high temporal resolution. The federal government is currently reviewing the entire authorisation process and developing proposals for optimisation. [2]