土壤重金属生物可利用性影响因素及模型预测

我国土壤环境污染形势严峻，在生物有效性(bioavailability)的测试评估和预测模型等方面的研究相对较少，导致不能精确地评估污染土壤的生态风险.作为生物有效性的重要反映指标，对土壤中镉(Cd)、砷(As)、铜(Cu)、锌(Zn)和铅(Pb)的生物可利用性(bioaccessibility)进行研究.筛选了已发表论文中生物可利用性与所对应的土壤性质的数据，并分析了它们之间的潜在关系，总结了现有的土壤重金属生物可利用性的测试方法，探究了生物可利用性含量与测试方法以及生物有效性含量之间的影响规律，并建立了生物可利用性含量的回归预测模型.结果表明，生物可利用性含量与重金属总含量间呈极显著(P<0.01)的正相关关系，与土壤pH相关性显著(P<0.05).测试方法的不同对生物可利用性含量有明显的影响，各测试方法测定的生物可利用性含量占比规律为：体外胃肠道模拟>化学试剂提取.各测试方法测定的Cd和Pb的生物可利用性含量占比均较高(均值分别为42.12%和37.33%),说明Cd和Pb较易于被生物体吸收，也应关注由此造成的生态风险.基于生物类型对测试方法进行了分组，以削弱不...

Effect Factors and Model Prediction of Soil Heavy Metal Bioaccessibility

The soil environmental pollution situation has been severe in recent years, but studies on evaluating with bioavailability testing and prediction models are lacking, which makes it difficult to accurately assess the ecological risks of contaminated soil. As an important indicator of bioavailability, the bioaccessibility of cadmium (Cd), arsenic (As), copper (Cu), zinc (Zn), and lead (Pb) in the soil was analyzed in this study. The bioaccessibility content and their corresponding soil property data were screened and systematically analyzed to explore the relationship between bioaccessibility content and soil properties. Furthermore, some testing methods for bioaccessibility were summarized to analyze the relationship between bioaccessibility content, test methods, and bioavailability content. Additionally, the bioaccessibility content prediction models were established. The results showed that there was a strong correlation between the bioaccessibility content and the total content of heavy metals (P<0.01) and a significant (P<0.05) correlation with the soil pH. Different test methods had obvious effects on bioavailability. The proportion of bioaccessibility content determined via various test methods was as follows:in vitro gastrointestinal tract simulation>chemical reagent extraction. The proportions of bioaccessibility content of Cd and Pb in natural soil were relatively high, with mean values of 42.12% and 37.33%, respectively, indicating that Cd and Pb had higher risks of being absorbed by soil organisms. Moreover, 30 bioaccessibility prediction models for five heavy metals were constructed, which involved the soil properties and test methods. The results of this study can provide scientific information and bioaccessibility prediction models that can help in accurately assessing the ecological risks of contaminated soil.