New integrated tools for risk assessment and decision making on a basin scale Jos van Gils, Elena Semenzin, Muriel Gevrey, Peter Von der Ohe, Bert van Hattum, Dick de Zwart, and …

Introduction Ecological status is threatened by different pressures (“multiple stress”, Segner) Among them toxic stress which to some degree covered by insufficient chemical status, however incomplete data sets for priority substances emerging pollutants mixture toxicity (reduced) bio-availability bio-accumulation

MODELKEY approach Weight of Evidence (WoE) approach to assess the risk of chemicals to the Good Ecological Status, based on different Lines of Evidence (LoE): Chemistry Biology Toxicology (also in DSS, Gottardo) pragmatic way to deal with conceptual uncertainties

stress can be differentiated for different groups Predicting toxic stress: Toxic units Ci LC50i Toxicity indicator: Toxic Units = with Ci = concentration of chemical i LC50i = lethal concentration (48h) of chemical i, for Invertebrates, Algae and Fish micro-algae (Selenastrum capricornutum) invertebrates (Daphnia magna) fish (Pimephales promelas) stress can be differentiated for different groups

Predicting toxic stress: msPAF PAF: potentially affected fraction (of species) msPAF: multi-substance PAF (mixture toxicity) Risk Assessment ò PAF 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 - 3 2 4 5 Cumulaitve probability Log Concentration ( m g/L) EQC ð HC L(E)C 50 or NOEC SSD bio-availability! Posthuma, L., Suter, G. W., II, and Traas, T. P., editors. 2002. Species Sensitivity Distributions in Ecotoxicology. Lewis Publishers, Boca Raton, FL, USA.

Observing effects: SPEAR indicator The SPEAR indicator (SPecies At Risk), species are classificied based on high physiological sensitivity (based on acute LC50) long generation time, low reproductivity reference community at risk not at risk  SPEAR ~ 50%

Ecological status – SPEAR indicator Ecological status

Predicted effects are observed ( Llobregat) 10 20 30 40 50 60 70 80 SPEAR [%] n = 30 - - 4 - - 3 3 - - 2 2 - - 1 1 Predicted toxic pressure Toxic Units Daphnia magna * Von der Ohe et al. 2009. Towards an Integrated Assessment of the Ecological and Chemical Status of European River Basins. IEAM 5, 50-61.

but large uncertainty, variability Predicted effects are observed ( Scheldt) msPAF predicted loss of species, based on LC50 values, is significantly related to the actually observed loss of species but large uncertainty, variability

Predicted stress confirmed in bio-assays Effect Predicted toxic pressure

MODELKEY approach Schmitt-Jansen

Cost-effective measures Prioritisation of sites/sources/chemicals tools in DSS (Gottardo) exposure model

Exposure modelling EXPOBASIN model: River & Basin Geometry River Hydrology & Hydraulics Fine sediment dynamics Transport and fate of chemicals Bio-availability and -accumulation Exposure, risk indicators Environmental conditions EXPOBASIN model: spatial relations between causes (pollution sources) and downstream effects (ecological risk) for quantitative and objective ranking of chemicals and/or pollution sources (including sediments and biota) easy application to all European river basins

Exposure modelling source A source B “local” impact “exported” impact based on TU as a risk indicator

Next steps towards cost-effective programmes of measures: systems analysis for selected chemicals, integrated source-oriented and effect-oriented approaches, integration of compartments water, air, soils, ground water enhanced multi-stressor assessments stressor-specific indicators … (Segner) exploring/enhancing “emerging” Europe-wide harmonised databases

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