Definition and use of Solution-focused Sustainability Assessment: A novel approach to generate, explore and decide on sustainable solutions for wicked problems.

This paper introduces Solution-focused Sustainability Assessment (SfSA), provides practical guidance formatted as a versatile process framework, and illustrates its utility for solving a wicked environmental management problem. Society faces complex and increasingly wicked environmental problems for which sustainable solutions are sought. Wicked problems are multi-faceted, and deriving of a management solution requires an approach that is participative, iterative, innovative, and transparent in its definition of sustainability and translation to sustainability metrics. We suggest to add the use of a solution-focused approach. The SfSA framework is collated from elements from risk assessment, risk governance, adaptive management and sustainability assessment frameworks, expanded with the 'solution-focused' paradigm as recently proposed in the context of risk assessment. The main innovation of this approach is the broad exploration of solutions upfront in assessment projects. The case study concerns the sustainable management of slightly contaminated sediments continuously formed in ditches in rural, agricultural areas. This problem is wicked, as disposal of contaminated sediment on adjacent land is potentially hazardous to humans, ecosystems and agricultural products. Non-removal would however reduce drainage capacity followed by increased risks of flooding, while contaminated sediment removal followed by offsite treatment implies high budget costs and soil subsidence. Application of the steps in the SfSA-framework served in solving this problem. Important elements were early exploration of a wide 'solution-space', stakeholder involvement from the onset of the assessment, clear agreements on the risk and sustainability metrics of the problem and on the interpretation and decision procedures, and adaptive management. Application of the key elements of the SfSA approach eventually resulted in adoption of a novel sediment management policy. The stakeholder participation and the intensive communication throughout the project resulted in broad support for both the scientific approaches and results, as well as for policy implementation.

The impact of an additional ecotoxicity test on ecological quality standards.

The present study aims to support decisions on whether or not to perform an extra toxicity test in order to improve environmental quality standards (EQSs). The impact of an additional ecotoxicity test was analyzed by predicting new ecotoxicity values with three different estimation methods and adding them to existing species sensitivity distributions (SSDs) on which the EQSs are based. The results show that EQSs are likely to increase due to increasing sample size, but the change also depends on the number of toxicity values available, the estimation method used and the representativeness of the species tested. The management consequences are illustrated in a case study on contaminated freshwater sediment in the Netherlands. It is shown that a slight increase of the EQS can result in a large reduction of sediment remediation costs without impairing regulatory protection levels. The paper identifies indicators that can be used to evaluate the potential impact of an extra ecotoxicity test.

Ranking of agricultural pesticides in the Rhine-Meuse-Scheldt basin based on toxic pressure in marine ecosystems.

Although risk assessments on a per-chemical basis are required during the registration procedure of pesticides, cumulative risks from the use of all pesticides on the variety of crops in a catchment area of a river are not assessed. The present study aimed to rank pesticides used in outdoor agricultural practice within the catchment of the rivers Rhine, Meuse, and Scheldt according to their potential toxic impact on the North Sea coastal ecosystem. Toxic pressure calculations (based on steady-state concentrations calculated with a multimedia fate model) and species-sensitivity distribution-based risk estimations were performed for pesticide emissions in the years 1998 (189 pesticides) and 2004 (133 pesticides). A ranking was established according to the relative contribution of single pesticides and crop types to the overall toxic pressure. Calculations were performed probabilistically to deal with parameter uncertainties. Only a few pesticides and crop types dominate overall toxic pressure because of emissions in both years, and the uncertainty appears to be caused largely by uncertainties in interspecies variances of aquatic toxicities. For 1998, these pesticides were fentin-acetate, with a median relative contribution (RCx) to the toxic pressure of multiple chemicals on an ecosystem of 0.43. For 2004, the pesticides that contributed most were pencycuron and paraquat-dichloride, with a median RCx, of 4.4 x 10(-2) and 3.9 x 10(-2), respectively. Pesticides applied to potato cropland and fruit trees contributed most to the overall toxic pressure.

Uncertainty in msPAF-based ecotoxicological effect factors for freshwater ecosystems in life cycle impact assessment.

Ecotoxicological effect factors are part of the analysis of relative impacts by chemical contaminants on ecosystems. Uncertainty distributions, represented by the 90% confidence interval, belonging to ecotoxicological effect factors for freshwater ecosystems were determined. This study includes 869 high production volume chemicals, related to 7 nonspecific toxic modes of action (TMoAs). The ecotoxicological effect factors are divided into a TMoA-specific part and a chemical-specific part. The 90% confidence interval of the TMoA-specific part of the effect factor ranges from 23 orders of magnitude for acrylate toxicity to 2 orders of magnitude for nonpolar narcosis. The range in the TMoA-specific part of the effect factor is mainly caused by uncertainty in the spread in toxic sensitivity between species (sigma(j)). Average uncertainty in the chemical-specific part of the effect factors depends on the number of species tested and ranges on average from a factor of 5 for more than 3 species tested to a factor of about 1,000 for 2 species tested. Average uncertainty in the ecotoxicological effect factors ranges from a factor of 100 for more than 3 species tested to a factor of nearly 10,000 for 2 species tested. It is recommended that the ecotoxicological effect factor of a chemical is based on toxicity data of at least 4 species.