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Content description:
Submerged macrophytes are an important structural and functional element of aquatic ecosystems. In the environmental risk assessment procedures for pesticide registration however, they are only considered fragmentarily. In the risk assessment the floating macrophyte Lemna is considered a model organism for macrophytes. Tests with the floating macrophyte Lemna are required for herbicides. A test with a submerged macrophyte is only required for herbicides if risks to aquatic plants (i.e. Lemna) are identified. In the revision of the guideline, all compounds with herbicidal mode of action (including plant growth regulators some fungicides) have to be tested with the standard macrophyte species Lemna. If Lemna is the most sensitive standard test organism, a test with a submerged macrophyte has to be performed additionally.
In 2008 a workshop was held in Wageningen on the risk assessment of aquatic macrophytes to pesticides (AMRAP Aquatic Macrophyte Risk Assessment for Plant Protection Products). The workshop recommends an adapted risk assessment scheme and identifies a number of gaps in knowledge and needs.
In this context the following research topics are possible:
1. Experimental work combined with literature research and
reporting.
Several topics can be studied:
- What is the influence of the length of the pre-growth period of the macrophytes on their sensitivity ? Does root development influence their sensitivity ?
- There is a lack of knowledge about the sensitivity of seeds or tubers to pesticides, for example seeds of Myriophyllum or tubers of Potamogeton pectinatus. There is a need for experimental guidance and a lack of information.
- Suitability of Myriophyllum aquaticum as test species in the context of its ecological and physiological traits; experiment how to optimize a test approach for this species.
- To test the effects of time variable exposure with an herbicide on submerged macrophyte species (Lab tests). The aim of the test is to determine the effects of different exposure regimes being constant in their concentration x time factor.
2. Data analysis combined with literature research and reporting:
- Gathering physiological and ecological traits of aquatic macrophytes and analysis of this dataset in the context of the risk assessment of pesticides for this group of organisms and in the context of the suitability of specific species in the risk assessment;
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