School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia; Centre for Environmental Sustainability and Remediation, RMIT University, Victoria, Australia; CDM Smith, Richmond, Victoria, Australia.
van de Graaff & Associates Pty Ltd, Mitcham, Victoria, Australia.
Chemosphere. 2018 Nov;210:193-203. doi: 10.1016/j.chemosphere.2018.06.138. Epub 2018 Jun 26.
Geochemical ratios between elements of environmental concern and Fe have been recommended for estimation of "background" concentrations of Cr, Cu, Ni and Zn in soil. However, little research has occurred to assess the consistency of geochemical ratios across soils developed in different environments. Broad application of generic geochemical ratios could result in under or over estimation of anthropogenic impacts to soil and subsequent inaccurate assessment of risk to the environment. A soil survey was undertaken in Victoria, Australia, including collection of samples (n = 622) from surface (0-0.1 m below ground level) and sub-surface (0.3-0.6 m below ground level) soils, overlying Tertiary-Quaternary basalt, Tertiary sediments and Silurian siltstones and sandstones. Samples were analyzed for metals and soil physical and chemical properties (particle size, cation exchange capacity, organic matter and pH). Geochemical correlations between elements in soils from different parent materials and environments were compared against geochemical relationships reported in Australia and internationally. Ratios of Cr and Fe were relatively consistent across parent materials, and comparable to published models for estimation of background Cr. Conversely, ratios between Cu, Ni, and Zn with Fe, were variable between soils developed in different weathering environments and/or soil depths. Alternative regression equations and rule based regression tree models were developed as an improved means for prediction of ambient background Cu, Ni and Zn concentrations in soil. Ambient background concentrations of Ni and Cr were predictable across parent materials and depths, allowing these models to be extended to soils across Australia and potentially internationally.
环境关注元素与铁之间的地球化学比值已被推荐用于估计土壤中铬、铜、镍和锌的“背景”浓度。然而，对于评估不同环境下形成的土壤中地球化学比值的一致性的研究还很少。广泛应用通用的地球化学比值可能导致对土壤人为影响的低估或高估，从而对环境风险的评估不准确。在澳大利亚维多利亚州进行了一项土壤调查，包括从覆盖第三纪-第四纪玄武岩、第三纪沉积物和志留纪粉砂岩和砂岩的表层（地下 0-0.1 米）和次表层（地下 0.3-0.6 米）土壤中采集样本（n=622）。对样本进行了金属和土壤物理化学特性（粒径、阳离子交换能力、有机质和 pH 值）的分析。比较了不同母质和环境土壤中元素之间的地球化学相关性与澳大利亚和国际上报告的地球化学关系。铬和铁之间的比值在不同母质之间相对稳定，与用于估计背景铬的已有模型相当。相比之下，铜、镍和锌与铁之间的比值在不同风化环境和/或土壤深度形成的土壤之间变化较大。开发了替代回归方程和基于规则的回归树模型，作为预测土壤中环境背景铜、镍和锌浓度的改进方法。镍和铬的环境背景浓度在母质和深度上具有可预测性，允许将这些模型扩展到澳大利亚和可能在国际上的土壤。
