Risk assessment for submerged macrophytes

Problem Despite their important role in aquatic ecosystems, submersed aquatic macrophytes are only poorly addressed in the Environmental Risk Assessment procedures for pesticides. Tests with submersed macrophytes are only required for herbicides if risks to aquatic plants (as tested on Lemna spp.) have been identified. It is being questioned whether toxicity tests with Lemna can be regarded as representative of effects on submerged macrophytes. For submersed macrophytes no internationally accepted guideline on laboratory or field tests exists.