When pesticides are applied, they may reach nearby surface waters and harm aquatic organisms living in streams, ponds or ditches. This is why the risk to fish, aquatic invertebrates, algae and aquatic plants from the use of pesticides is assessed.
To assess these risks, the hazard of an active substance (and its relevant breakdown products or metabolites) to these aquatic organisms is compared to the expected exposure.
You can find which data needs to be submitted to describe the hazard in the Regulation setting data requirements for active substances and plant protection products.
More information on how exposure is calculated can be found in the page describing the assessment of the fate and behaviour of active substances in surface water.
The EFSA Guidance Document on tiered risk assessment for plant protection products for aquatic organisms in edge-of-field surface waters outlines a tiered risk assessment scheme covering acute and chronic effect assessment schemes for aquatic organisms and how to link observed effects to exposure estimates.
Regulation (EU) No 546/2011 on uniform principles for evaluation and authorisation of plant protection products contains the decision-making criteria for approving active substances or authorising plant protection products. These criteria reflect the protection goals, also for fish, aquatic invertebrates, algae and aquatic plants.