College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430081, China; Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China.
School of Environment and Natural Resources, Ohio State University, Columbus, OH, 43210, USA.
Environ Pollut. 2020 Aug;263(Pt B):114501. doi: 10.1016/j.envpol.2020.114501. Epub 2020 Apr 2.
Soils have the ability to modify contaminant bioavailability and toxicity. Prediction the modifying effect of soil on arsenic phytoaccumulation and phytoavailability using either soil property data or soil chemical extraction data in risk assessment of contaminated soil is highly desirable. In this study, plant bioassays important to ecological receptors, were conducted with 20 soils with a wide range in chemical and physical soil properties to determine the relationships between As measured by soil chemical extraction (soil pore water, Bray-1, sodium phosphate solution, hydroxylamine hydrochloride, and acid ammonium oxalate) or soil physico/chemical properties on arsenic phytotoxicity and phytoaccumulation. Soil pore water As and Bray-1 extracted As were significantly (P < 0.01) correlated with lettuce tissue As and those extractants and sodium phosphate were correlated with ryegrass tissue As. Hydroxylamine and acid ammonium oxalate extractions did not correlate with plant bioassay endpoints. Simple regression results showed that lettuce tissue relative dry matter growth (RDMG) was inversely related to tissue As concentration (r = 0.85, P < 0.01), with no significant relationship for ryegrass. Soil clay exhibited strong adsorption for As and significantly reduce tissue As for lettuce and ryegrass. In addition to clay content, reactive aluminum oxide (AlOx), reactive Fe oxide (FeOx) and eCEC was inversely related to ryegrass tissue As. Multiple regression equation was strongly predictive (r = 0.83) for ryegrass tissue As (log transformed) using soil AlOx, organic matter, pH, and eCEC as variables. Soil properties can greatly reduce contaminant phytoavailability, plant exposure and risk, which should be considered when assessing contaminant exposure and site-specific risk in As-contaminated soils.
土壤具有改变污染物生物利用度和毒性的能力。在受污染土壤的风险评估中，使用土壤性质数据或土壤化学提取数据来预测土壤对砷植物积累和植物有效性的修饰作用是非常理想的。在这项研究中，用 20 种具有广泛化学和物理土壤性质的土壤进行了对生态受体重要的植物生物测定，以确定土壤化学提取（土壤孔隙水、Bray-1、磷酸钠溶液、羟胺盐酸盐和草酸铵）或土壤理化性质与砷植物毒性和植物积累之间的关系。土壤孔隙水 As 和 Bray-1 提取的 As 与生菜组织中的 As 显著相关（P < 0.01），而这些提取剂和磷酸钠与黑麦草组织中的 As 相关。羟胺和草酸铵提取与植物生物测定终点无关。简单回归结果表明，生菜组织相对干物质生长（RDMG）与组织中的 As 浓度呈负相关（r = 0.85，P < 0.01），而黑麦草则没有显著关系。土壤粘粒对 As 具有很强的吸附作用，显著降低了生菜和黑麦草的组织中的 As。除粘粒含量外，反应性氧化铝（AlOx）、反应性氧化铁（FeOx）和 eCEC 与黑麦草组织中的 As 呈负相关。使用土壤 AlOx、有机质、pH 值和 eCEC 作为变量的多元回归方程对黑麦草组织中的 As（对数转换）具有很强的预测能力（r = 0.83）。土壤性质可以大大降低污染物的植物有效性、植物暴露和风险，在评估受污染土壤中的污染物暴露和特定地点风险时应予以考虑。
