Biological organisation

 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Background and Need for Workshop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Workshop Purpose and Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Participation and Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Workgroup Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Workgroup 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Problem formulation: Context for selenium risk assessment . . . . . . . . . . . . . . . . . . . . . 9 Selenium is a global problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Case studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Conceptual model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 How to investigate a potential selenium problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Workgroup 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Environmental partitioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Workgroup 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Bioaccumulation and trophic transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Workgroup 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Selenium toxicity to aquatic organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Workgroup 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Risk characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Importance of problem formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Risk characterization: Unique challenges concerning selenium . . . . . . . . . . . . . . . . . . 26 Risk management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Uncertainties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Overall Workshop Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Appendix: SETAC Pellston Workshop Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 List of Figures Figure 1 Conceptual model depicting Se dynamics and transfer in aquatic ecosystems . . . . . . . . . . . . .11 Figure 2 Hierarchy of effects across levels of biological organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Figure 3 Potential sources of Se to aquatic systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Figure 4 Selenium species associated with major processes in aquatic systems . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Figure 5 Partitioning of Se among environmental compartments in a typical aquatic system. . . .16 Figure 6 Selenium enrichment and trophic transfer in aquatic food webs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Figure 7 Selenium accumulation in different species of algae, invertebrates, and fish . . . . . . . . . . . . . . . .20 Figure 8 Conceptual pathway of Se transfer in aquatic ecosystems and relative certainty with which Se concentrations in environmental compartments can be assessed in making accurate characterizations of risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 List of Tables Table 1 Assessment endpoints and measures of exposure and effect for aquatic and aquaticlinked organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Table 2 Uncertainties and recommendations for future research pertaining to toxicity of Se species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 Ecological Assessment of Selenium in the Aquatic Environment 4 

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