• Exposure and ecological effects of toxic mixtures at field-relevant concentrations. Model validation and integration of the SSEO programme

      Posthuma L; Vijver MG; LER; SEC (Rijksinstituut voor Volksgezondheid en Milieu RIVMAlterraWageningenRadboud Universiteit NijmegenVrije UniversiteitAmsterdamWageningen University and Research Centre WURIMARES, 2007-12-14)
      Local environmental conditions need be taken into account to assess the impacts of diffuse environmental pollution on ecosystems. This was shown in an evaluation of the scientific results of the Dutch Stimulation Programme System-Oriented Ecotoxicological Research, led by RIVM.<br>Effects of diffuse pollution on the environment were studied at three contaminated areas in the Netherlands: the flood plains of a large lowland river (Waal), a tidal area (Biesbosch) and a peat soil area (near Vinkeveen). Diffuse pollution is present in these areas. Type and magnitudes of effects were determined and analysed.<br>The integrated results analysis showed that effects ranged from absent or low, to clearly visible and large. The magnitude of effects depended on the local composition of the mixture, the local characteristics of the soil, the water or the sediment, and the sensitivity of the local micro-organisms, plants and animals being exposed. The combination of these three characteristics influenced the type and magnitude of impacts.<br>The measurement methods and the modelling analyses used in the research programme appeared to be useful for managing the risks of diffuse site contamination. Application of these methods and analyses is useful for the Dutch situation, given the large areas with diffuse contamination. Sanitation of large, diffusely contaminated areas is not a practicable solution. RIVM recommends the development of a toolbox for ecological risk assessment. Application of such a toolbox will lead to a better assessment of local risks, and the assessment will be based more on ecological approaches. Eventually, this will result in linkage between substance-oriented policies and the management of contaminated sites.<br>