Zhu Xiaodong, Yang Fen, Wei Chaoyang, Liang Tao
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Beijing, 100101, China.
University of the Chinese Academy of Sciences, Beijing, 100049, China.
Environ Geochem Health. 2016 Feb;38(1):233-41. doi: 10.1007/s10653-015-9711-2. Epub 2015 May 16.
The objective of this study was to examine whether a single model could be used to predict the bioaccessibility of heavy metals in soils in two adjacent areas and to determine the feasibility of using existing data sets of total metal concentrations and soil property parameters (e.g., pH, total organic carbon, and soil texture) when predicting heavy metal bioaccessibility. A total of 103 topsoil samples were collected from two adjacent areas (Baotou and Bayan Obo). A total of 76 samples were collected from Baotou, and 27 were collected from Bayan Obo. The total and bioaccessible concentrations of arsenic (As), copper (Cu), lead (Pb), and zinc (Zn) were measured following complete composite acid digestion and a simple bioaccessibility extraction test. The average total concentrations of As, Cu, Pb, and Zn were 8.95, 27.53, 28.40, and 79.50 mg/kg, respectively, in Baotou and 18.12, 30.75, 38.09, and 87.62 mg/kg in Bayan Obo. Except for As, these values were similar in both areas. The average bioaccessible heavy metal concentrations (Bio-HMs) for each target HM were also similar. In Baotou, the average Bio-HM values for As, Cu, Pb, and Zn were 1.16, 3.76, 16.31, and 16.10 mg/kg, respectively, and 1.26, 2.51, 14.31, and 8.68 mg/kg in Bayan Obo. However, the relative bioaccessibilities for each HM in Baotou were greater than those in Bayan Obo, with mean values for Pb, Zn, Cu, and As of 57, 20, 17, and 12 %, respectively, in Baotou and 40, 11, 9, and 8 % in Bayan Obo. In both areas, prediction models were successfully created using heavy metal concentrations and soil physicochemical parameters; however, models of the same target element differed between the areas, which indicated that a common model for both sites does not exist. Bio-HMs were highly affected by soil properties, which were found to differ between the adjacent areas. In addition, soil properties with large variations played major roles in the predictive models. This study highlights the importance of incorporating physical and chemical parameters that vary greatly when building predictive models of heavy metal bioaccessibility in soil. A similarity in soil properties between areas might be a prerequisite for the creation of a common predictive model for soil Bio-HMs.
本研究的目的是检验是否可以使用单一模型来预测两个相邻区域土壤中重金属的生物可及性，并确定在预测重金属生物可及性时使用总金属浓度和土壤性质参数（如pH值、总有机碳和土壤质地）的现有数据集的可行性。从两个相邻区域（包头和白云鄂博）共采集了103个表层土壤样本。其中从包头采集了76个样本，从白云鄂博采集了27个样本。通过完全混合酸消解和简单的生物可及性提取试验，测定了砷（As）、铜（Cu）、铅（Pb）和锌（Zn）的总量和生物可及浓度。包头地区As、Cu、Pb和Zn的平均总浓度分别为8.95、27.53、28.40和79.50mg/kg，白云鄂博地区分别为18.12、30.75、38.09和87.62mg/kg。除As外，两个地区的这些值相似。每个目标重金属的平均生物可及重金属浓度（Bio-HMs）也相似。在包头，As、Cu、Pb和Zn的平均Bio-HM值分别为1.16、3.76、16.31和16.10mg/kg，在白云鄂博分别为1.26、2.51、14.31和8.68mg/kg。然而，包头地区每种重金属的相对生物可及性高于白云鄂博地区，包头地区Pb、Zn、Cu和As的平均值分别为57%、20%、17%和12%，白云鄂博地区分别为40%、11%、9%和8%。在两个地区，均利用重金属浓度和土壤理化参数成功建立了预测模型；然而两个地区相同目标元素的模型不同，这表明不存在适用于两个地点的通用模型。Bio-HMs受土壤性质的影响很大，相邻区域的土壤性质存在差异。此外，变化较大的土壤性质在预测模型中起主要作用。本研究强调了在建立土壤中重金属生物可及性预测模型时纳入变化很大的物理和化学参数的重要性。区域间土壤性质的相似性可能是建立土壤Bio-HMs通用预测模型的前提条件。
