National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA.
Environ Health Perspect. 2011 Nov;119(11):1629-34. doi: 10.1289/ehp.1003352. Epub 2011 Jul 13.
Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessments and remediation goals, convenient, rapid, reliable, and inexpensive tools are needed to determine soil As bioavailability.
We evaluated inexpensive methods for assessing As bioavailability in soil as a means to improve human exposure estimates and potentially reduce remediation costs.
Nine soils from residential sites affected by mining or smelting activity and two National Institute of Standards and Technology standard reference materials were evaluated for As bioavailability, bioaccessibility, and speciation. Arsenic bioavailability was determined using an in vivo mouse model, and As bioaccessibility was determined using the Solubility/Bioavailability Research Consortium in vitro assay. Arsenic speciation in soil and selected soil physicochemical properties were also evaluated to determine whether these parameters could be used as predictors of As bioavailability and bioaccessibility.
In the mouse assay, we compared bioavailabilities of As in soils with that for sodium arsenate. Relative bioavailabilities (RBAs) of soil As ranged from 11% to 53% (mean, 33%). In vitro soil As bioaccessibility values were strongly correlated with soil As RBAs (R² = 0.92). Among physicochemical properties, combined concentrations of iron and aluminum accounted for 80% and 62% of the variability in estimates of RBA and bioaccessibility, respectively.
The multifaceted approach described here yielded congruent estimates of As bioavailability and evidence of interrelations among physicochemical properties and bioavailability estimates.
土壤砷（As）生物可利用性的评估可能会通过改善人类暴露估计来深刻影响污染场地所需的修复程度。由于土壤 As 生物可利用性估计的微小调整可能会显著改变风险评估和修复目标，因此需要方便、快速、可靠和廉价的工具来确定土壤 As 生物可利用性。
我们评估了评估土壤中 As 生物可利用性的廉价方法，作为改善人类暴露估计并可能降低修复成本的一种手段。
评估了来自受采矿或冶炼活动影响的住宅场地的 9 种土壤和 2 种美国国家标准与技术研究院标准参考物质的 As 生物可利用性、生物可及性和形态。使用体内小鼠模型确定 As 生物可利用性，使用 Solubility/Bioavailability Research Consortium 体外测定法确定 As 生物可及性。还评估了土壤中 As 的形态和选定的土壤物理化学性质，以确定这些参数是否可用作 As 生物可利用性和生物可及性的预测因子。
在小鼠测定中，我们比较了土壤中 As 的生物可利用性与砷酸钠的生物可利用性。土壤 As 的相对生物可利用性（RBA）范围为 11%至 53%（平均值为 33%）。体外土壤 As 生物可及性值与土壤 As RBA 呈强相关性（R²=0.92）。在物理化学性质中，铁和铝的组合浓度分别解释了 RBA 和生物可及性估计值变异性的 80%和 62%。
这里描述的多方面方法得出了一致的 As 生物可利用性估计值，并证明了物理化学性质和生物可利用性估计值之间的相互关系。
