Water quality objectives for pesticides in surface water

Page reviewed: 16/06/2025

Water quality objectives (WQO) are used for calculation of pesticide toxicity in surface water and specifies the highest concentration where no negative effects of a substance can be expected in the water ecosystem.

The water quality objectives (WQO) presented below are used in the National environmental monitoring of pesticides and are not legally binding quality standards. Since the concentration considered harmful is substance-specific, separate guideline values are assigned to each substance.

WQO for surface water have been developed in various ways. In environmental monitoring, the primary reference is the water quality objectvies published by the Swedish Environmental Protection Agency (Naturvårdsverket) on its website (in Swedish). These values correspond to the Predicted No Effect Concentrations (PNEC values), which are established during the registration process within the EU.

More information on how these WQO have been developed can be found in a report created in connection with the update of guideline values for a number of substances: Förslag till uppdatering av riktvärden för växtskyddsmedel i ytvatten (in Swedish)

For a few substances where no WQO exist, Environmental Quality Standards (EQS) for priority substances and river basin specific pollutants, from the Swedish Agency for Marine and Water Management’s regulation HVMFS 2019:25 (HaV, 2020) are used. However, if there is a WQO established by the Swedish Environmental Protection Agency, that value takes precedence—even for substances that also have EQS values.

For substances that lack updated WQO and are not included in the regulation or in the Swedish Chemicals Agency’s lists from 2004 and 2007, other preliminary sources are used according to the reference list below.