Assessing the variability of the bioavailable fraction of zinc at the global scale using geochemical modeling and soil archetypes
Assessing the variability of the bioavailable fraction of zinc at the global scale using geochemical modeling and soil archetypes
复制标题
使用地球化学模型和土壤原型评估全球范围内锌的生物可利用部分的变异性
DOI：
10.1007/s11367-014-0841-z
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
L. Deschênes
中科院分区：
文献类型：
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作者：
Geneviève Plouffe;Cécile Bulle;L. Deschênes
目的：与生命周期评估（LCA）中使用的总金属毒性电位一样，由于毒性与生物可利用金属部分相关，因此有时会引入偏差并显著影响LCA结果的有效性。方法采用WHAM 6.0地球化学形态模型，计算不同土壤类型锌的生物有效组分。在此之前，WHAM模型仅使用全球可用的土壤特性（土壤质地、pH值、阳离子交换容量、碳酸盐和有机质含量）对土壤的可用性进行了验证，并与使用经验回归进行了比较。结果和讨论结果证实，相对于现场数据，对于各种土壤，WHAM可以以小于2个数量级的不确定度预测Zn的生物有效分数（41%为同一数量级），得出的估计结果在等级和值方面优于经验回归结果。锌的可溶态和真溶态锌的世界BFs分别超过6 ~ 18个数量级，从而证实了考虑空间变异性的重要性。根据影响物种形成的土壤特性，总共定义了231种土壤原型。结论与实验值相比，WHAM法测得的可溶性锌比真溶液锌能更可靠地反映锌的生物利用度。与经验回归估计相比，用WHAM 6.0模型获得的可溶性锌估计在值和等级方面更接近现场数据。在有机土壤中，要得到真正的溶液锌，需要提纯。虽然不是详尽无遗，但验证过程涵盖了世界上相当大比例的土壤，因此表明该方法有望在全球范围内研究锌的生物有效性。
PurposeTotal 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.MethodsHere, 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 discussionThe 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.ConclusionsWhen 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.