Department of Agricultural Chemistry, The University of Agriculture Peshawar, Pakistan; Environment Department, The University of York, Heslington, York, UK.
Environment Department, The University of York, Heslington, York, UK; Department of Aquatic Ecology and Environmental Biology, Raboud University Nijmegen, The Netherlands.
J Environ Manage. 2018 Sep 15;222:260-267. doi: 10.1016/j.jenvman.2018.05.076. Epub 2018 May 31.
A significant body of knowledge suggests that soil solution pH and dissolved organic carbon (DOC) strongly influence metal concentrations and speciation in porewater, however, these effects vary between different metals. This study investigated the factors influencing soil and soil solution concentrations of copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) under field conditions in upland soils from UK having a wide range of pH, DOC and organic matter contents. The study primarily focussed on predicting soil and soil solution metal concentrations from the data on total soil metal concentrations (HNO extracts) and soil and soil solution properties (pH, DOC and organic matter content). We tested the multiple regression models proposed by Tipping et al. (2003) to predict heavy metal concentrations in soil solutions and the results indicated a better fit (higher R values) in both studies for Pb compared to the Zn and Cu concentrations. Both studies observed consistent negative relationships of metals with pH and loss on ignition (LOI) suggesting an increase in soil solution metal concentrations with increasing acidity. The positive relationship between Pb concentrations in porewater and HNO extracts was similar for both studies, however, similar relationships were not found for the Zn and Cu concentrations because of the negative coefficients for these metals in our study. The results of this study conclude that the predictive equations of Tipping et al. (2003) may not be applicable to the field sites where the range of DOC and metal concentrations is much lower than their study. Our study also suggests that the extent to which metals are partitioned into soil solution is lower in soils with a higher organic matter contents due to binding of these metals to soil organic matter.
大量知识表明，土壤溶液 pH 值和溶解有机碳 (DOC) 强烈影响孔隙水中金属的浓度和形态，但这些影响因金属种类而异。本研究在英国高地土壤中调查了影响土壤和土壤溶液中铜 (Cu)、铅 (Pb)、镍 (Ni) 和锌 (Zn) 浓度的因素，这些土壤的 pH 值、DOC 和有机质含量范围很广。该研究主要侧重于从总土壤金属浓度 (HNO3 提取) 和土壤及土壤溶液特性 (pH 值、DOC 和有机质含量) 数据预测土壤和土壤溶液金属浓度。我们测试了 Tipping 等人提出的多元回归模型（2003 年）来预测土壤溶液中的重金属浓度，结果表明，与 Zn 和 Cu 浓度相比，这两项研究中 Pb 的拟合度（更高的 R 值）更好。两项研究都观察到金属与 pH 值和灼烧损失（LOI）呈负相关，表明随着酸度的增加，土壤溶液中金属浓度增加。这两项研究都观察到了土壤溶液中 Pb 浓度与 HNO3 提取液之间的正相关关系，但对于 Zn 和 Cu 浓度，由于这些金属在我们的研究中具有负系数，因此并未发现类似的关系。本研究的结果表明，Tipping 等人的预测方程（2003 年）可能不适用于 DOC 和金属浓度范围远低于其研究的野外地点。我们的研究还表明，由于这些金属与土壤有机质结合，在有机质含量较高的土壤中，金属分配到土壤溶液中的程度较低。
