title: Analyzing the Limitations and the Applicability Domain of Water-Sediment Transformation Tests like OECD 308.
abstract: The assessment of chemical degradation rates from water-sediment experiments like for instance OECD 308 is challenging due to parallel occurrence of processes like degradation, sorption and diffusive transport, at different rates in water and sediment or at their interface. To systematically and quantitatively analyze this limitation, we generated artificial experiment data sets using model simulations and then used these data sets in an inverse modeling exercise to estimate degradation half-lives in water and sediment (DegT50watand DegT50sed), which then were evaluated against their true values. Results were visualized by chemical space diagrams that identified those substance property combinations for which the OECD 308 test is fundamentally inappropriate. We show that the uncertainty in estimated degradation half-lives in water increases as the process of diffusion to the sediment becomes dominant over degradation in the water. We show that in theory the uncertainty in the estimated DegT50sedis smaller than the uncertainty in the DegT50wat. The predictive value of our chemical space diagrams was validated using literature transformation rates and their uncertainties that were inferred from real water-sediment experiments.
authors: Alterra - Wageningen UR , P.O. Box 47, 6700 AA Wageningen, The Netherlands.
authors: Mechteld M S
authors: MM
authors: Ter Horst
authors: Aquatic Ecology and Water Quality Management Group, Wageningen UR , P.O. Box 47, 6700 AA Wageningen, The Netherlands.
authors: Albert A
authors: AA
authors: Koelmans
mesh_terms: D019015:Geologic Sediments / Q000737:chemistry*; D008962:Models, Theoretical; D066150:Organisation for Economic Co-Operation and Development; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical
chemical_list: D014874:Water Pollutants, Chemical; D014867:Water