Bioconcentration of triphenyltin (TPT) and tributyltin (TBT) was studied in the freshwater organisms Daphnia magna (zooplankton), Chironomus riparius (sediment organism) and Thymallus thymallus (fish yolk‐sac larvae). TPT bioconcentration factors (BCFs) at pH 8 were highest for Thymallus (2200), followed by Chironomus (680) and Daphnia (190). The differences could not be fully explained by different total lipid contents. Metabolism and lower bioconcentration were observed for TBT in Chironomus. The BCFs of both TBT and TPT were higher at pH 8 than at pH 5, but the difference was much less pronounced than predicted by the octanol–water partition model. This suggests that, besides the hydroxide species (TBTOH and TPTOH), the cations (TBT+ and TPT+) are also taken up by the organisms to some extent and that the octanol–water partition model underestimates the uptake of the charged species. Low concentrations of humic substances (HS) led to small reduction in the bioconcentration of TPT in Daphnia and Thymallus, and a significant reduction occurred at relatively high concentrations of HS (>10 mg C l−1). The results of this study provide an important basis for future investigations aiming at a better understanding of the bioavailability and fate of TBT and TPT in freshwater ecosystems. © 1998 John Wiley & Sons, Ltd.

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Almost a book within the book this chapter collates eight expert reflections on Knowledge Visualization; what it is and what it could or should be. An average of 825 words long, topics span from representation, storytelling, and criticizing the lack of theory, to communication, analytics for the masses and reasoning, to trendy Visual Thinking and creativity beyond PowerPoint. These individual views provide a picture of the present and the future of a discipline that comes at precisely the right time. Despite the diverse character of its parts, written by academics and practitioners alike, this unique compilation constitutes a whole, a facetted answer to the question in its title, thus aiming to convey a common understanding of visualizing the true resource of our time, knowledge. S. Bertschi ( ) loginb Consulting, Westcliff-on-Sea,

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