Are Free Ion Activity Models Sufficient Alternatives to Biotic Ligand Models in Evaluating Metal Toxic Impacts in Terrestrial Environments?

Mikolaj Owsianiak, Ralph K. Rosenbaum, Henrik Fred Larsen, Michael Zwicky Hauschild

    Research output: Contribution to conferencePosterResearch

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    Abstract

    Metal partitioning between solid and aqueous phases and speciation in soil pore water control the bioavailability of toxic forms of metals, while protons and base cations can mitigate metal ecotoxicity by competitive interactions with biotic ligands. e employment of BLMs to evaluate toxicity potential of metals in soils results in site-specic toxicity scores due to large variability of soil properties and dierences in ionic composition. Unfortunately, terrestrial BMLs are available only for few metals and few organisms, thus their applicability to hazard ranking or toxic impact assessment is low and alternatives must be found. In this study, we compared published terrestrial BLMs and their potential alternatives such as free ion activity models (FIAM), for applicability in addressing metal toxic impacts in terrestrial environments. A set of 1300 soils representative for the whole world is employed to calculate EC50 and thereafter hazardous concentration HC50 (geometric mean of all EC50) for these terrestrial organisms, for which both TBLMs and FIAMs are available. Results showed that median HC50 for all soils predicted with BLMs range 2 and 3 orders of magnitude for copper and nickel, respectively. In all cases, predictions of FIAMs fall within the range of values predicted with BLMs, and toxicity ratio of copper to nickel is accurately predicted with both models. us, both models are able to distinguish between the two metals in terms of their average toxicity. Given that the calculated toxicity scores show large variability even for soils located in close proximity to each other, selection of FIAMs is also justied in deriving soil quality criteria. It remains to be investigated at what spatial scale the FIAMs are a good alternative to TBLMs in evaluating metal toxic impacts in terrestrial environments.
    Original languageEnglish
    Publication date2011
    Number of pages437
    Publication statusPublished - 2011
    EventSociety of Environmental Toxicology and Chemistry : Navigating Environmental Challenges: Historical Lessons Guiding Future Directions - Boston, United States
    Duration: 13 Nov 201117 Nov 2011

    Conference

    ConferenceSociety of Environmental Toxicology and Chemistry : Navigating Environmental Challenges: Historical Lessons Guiding Future Directions
    CountryUnited States
    CityBoston
    Period13/11/201117/11/2011

    Bibliographical note

    13–17 November

    Cite this

    Owsianiak, M., Rosenbaum, R. K., Larsen, H. F., & Hauschild, M. Z. (2011). Are Free Ion Activity Models Sufficient Alternatives to Biotic Ligand Models in Evaluating Metal Toxic Impacts in Terrestrial Environments?. Poster session presented at Society of Environmental Toxicology and Chemistry : Navigating Environmental Challenges: Historical Lessons Guiding Future Directions, Boston, United States.