| Contaminants in aquatic sediments are only partly available for transport or uptake by biota. This means that transport risks and ecological risks of for instance trace metals and organic micropollutants depend on the mobile or bioavailable fraction. The past years several methods have been developed to quantify these fractions and they have been tested mainly in laboratory settings. For proper assessment of risks, however, important questions are (a) whether these methods can be used in situ and (b) whether in situ bioavailability and mobility changes can be expected on a temporal scale, under anticipated climate scenarios, and what the main differences and implications are for the five catchments addressed in Aquaterra. The temporal changes will be addressed mainly for trace metals in the Meuse catchment where redox changes play a role. For organic contaminants we will include samples of several catchments and have a special look at the effects of carbonaceous materials (soots, chars) on bioavailability and mobility. |
