Integrating the results of system-oriented ecotoxicological research into a validated, operational ecological risk assessment toolbox for evaluating the influence of exposure from mixtures of toxic substances at the ecosystem-level

A decision-support toolbox for environmental management purpose is assembed form exiting ecotoxicological effect models. Using the informatiom and insights generated in SP SOER phase 1 projects, the available models are tested, calibrated, validated and adapted where necesarry. hte project will yield a decision-support toolbos including a set of guidlelines that instruct users when and how to use certain tools, and how to interpret their output, uncluding explicit use limitations. The significance of the proposed project is that scientific infrmation of a range of source is combined and eventuallly put to work for improving reulatory decision making for a variety of current assessment endpoints, especially those identified by SP-SOEr. The scientific objective is to do the combination in a scientifically sound way, be it that the end-product is for pragmatic use. Building on available expertise with ecotoxicologal effecr mdeling, the RIWM/RIZA/Alterra group starts the study from the in-house available models (CATS, IQ-tox, HERBERTS, OMEGA, PERPEST, PODYRAS) and their current applicatins. Other models that have been identified as potentially useful (RAM), or have beenh selected for use in SP-SOER phase 1 projects (AQUATOX) will be included, hiring external expertise from other research groups (t.b.d.). The project consists of four phases/activity types: Testing Existing models are parameterised with the SP-SOER data sets to test their applicability and performance in the contect of SP-SOER defined assessment endpoints. The goals of the testing phase are initial validation and calibration (if of impotance) of models and a classification (model can be adopted, adapted or abandoned regarding their uselfulness for the toolbox and the assessment problems). Comparison Suitable models will be scientifically compared in the output heu give for the SP-SOER data sets. Fot this comparison the output will be weighted on the basis of the concepts and extapolation methods on which the models are base. The goals of the comparison phase is crossbreeding to improve the modelling tools. Integrating models with field data Confront the output of the models with measured field data (from SP-SOER first phase an other). At this stage, the models are tested for their ability to describe and explain the specific ecotoxicological effects observed in the earlier phase-1 SP-SOER studies. At this stage, scientific conformation of the actual model applicability (model validity) in specific situations is obtained. Goal is to gain insight in the scope of the applicability of the model for AP-SOER. Formatting the toolbox Following scientific confirmation and science-based model adaptation, attention is given to adapt models where possible in order to limit input data requirements to what is or can become daily feasible practice. This will yields a compromise between optimal science and optimal use, with specified validity as target, adopting the ´80/20 rule` of optimising effort/result ratio. Flowchart of guidelines will be set up, when to use which tool given certain data and problems. The goal is to produce straight and simple guidelines when to use which models and how to compare their output to arrive at an overall risk assessment.