The aim of the workshop was to discuss and report current thinking on when and how species sensitivity distributions (SSDs) should be used and how the methodology could be further developed to improve the quality and usefulness of decision making in environmental protection and management of chemicals.
The workshop covered the broader aspects of the use of SSDs in environmental protection and management, recent developments and specific case studies. In addition, there were sessions which focused on ecological considerations, statistical considerations and regulatory considerations. There was general consensus that, where data permit, the SSD approach should provide a more useful and transparent assessment of hazard thresholds than a deterministic approach using generic assessment factors. However, validation against field and mesocosm data is required where data permit, the SSD approach should provide a more useful and transparent assessment of risks than a deterministic approach using generic assessment factors. The ability to quantify uncertainty is important but could be used more explicitly in decision-making. There is also a need for better validation against field and mesocosm data. It was further agreed, that the SSD methodology is a valuable regulatory and management tool since it can give more insight into the potential ecological effects than the assessment factor method (enabling better problem definitions) and it yields more generalisable results than a mesocosm-based methodology.
For the future, it was proposed that a compendium of current best practices, the state of the science and answers to frequently asked questions would facilitate acceptance of SSDs by regulators and risk managers and their implementation in regulation and management. The compendium should be a technical document aimed at users with knowledge of SSDs and ecosystems. However, this would limit the usefulness of the compendium and therefore another document suitable for a general audience is also necessary.
In line with current uses in decision making, various research areas were identified to improve the usefulness and validity of output generated with SSDs to solve the array of problems encountered. The research areas identified in the various syndicate sessions have been listed in Table 1. Although not given a priority during the workshop, the report authors will seek an indication of priority for the work from the workshop attendees.
The table below collates the research ideas mentioned in the Syndicate sessions, and thereafter collated and sorted into subgroups. In some cases, similar suggestions were merged. The subgroups are, first, the use of SSDs in various decision contexts (protection, quantitative assessment, diagnosis). Secondly, in any decision context, the output of SSDs should be relevant for the ecosystem situation considered; this encompasses various research needs. Thirdly, guidelines should be adapted to accommodate standardisation for criteria setting under novel scientific insights, as well as novel uses of SSDs in other context. The fourth area addresses the underlying improvements that can be made in modelling as well as in data used for assessments. Again, various options are given. Attention for accommodating further knowledge sources, such as mode of action and body burdens is foreseen. Finally, decision making with SSDs requires attention for uncertainties, their types and origins and the options for reducing uncertainty.
Table 1: Identified research areas