Assessing the variability of the bioavailable fraction of zinc at the global scale using geochemical modeling and soil archetypes

Plouffe, Geneviève; Bulle, Cécile et Deschênes, Louise (2015). « Assessing the variability of the bioavailable fraction of zinc at the global scale using geochemical modeling and soil archetypes ». The International Journal of Life Cycle Assessment, 20(4), pp. 527-540.

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Purpose Total metal-based toxicity potentials, like the ones used in life cycle assessment (LCA), can sometimes introduce bias and significantly affect the validity of LCA results since toxicity is associated with the bioavailable metal fraction. Methods Here, the bioavailable fraction of zinc (Zn) for world soil types is obtained using the WHAM 6.0 geochemical speciation model. Prior to this, the usability of the WHAM model for soils using only globally available soil properties (soil texture, pH, cation exchange capacity, carbonate, and organic matter content) was validated with experimental soil data and compared to the use of empirical regressions. Results and discussion The results confirm that WHAM can predict Zn bioavailable fraction with an uncertainty of less than 2 orders of magnitude—41 % being of the same order of magnitude—for a wide variety of soils relative to field data, yielding estimates that are better than empirical regression results in terms of rank and value. World BFs for Zn span over 6 to 18 orders of magnitude for soluble and true solution Zn, respectively, thus confirming the importance of considering spatial variability. In total, 231 soil archetypes are defined based on the soil properties that influence speciation. Conclusions When compared to experimental values, soluble Zn obtained with WHAM seems to constitute a more reliable indicator of the bioavailable fraction of Zn than true solution Zn. Estimates obtained with the WHAM 6.0 model for soluble Zn were closer to field data in terms of value and rank as compared to estimates obtained with empirical regressions. Refining is required to obtain true solution Zn in organic soils. Although not exhaustive, the validation process covers a considerable proportion of world soils, therefore indicating that the method is promising to study Zn bioavailability at the global scale

Type: Article de revue scientifique
Mots-clés ou Sujets: s Bioavailability . Life cycle impact assessment . Metal speciation . Modeling . Terrestrial ecotoxicity . Zinc
Unité d'appartenance: École des sciences de la gestion
Déposé par: Cécile Bulle
Date de dépôt: 01 nov. 2022 09:57
Dernière modification: 01 nov. 2022 09:57
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