Stevens Brooke N, Betts Aaron R, Miller Bradley W, Scheckel Kirk G, Anderson Richard H, Bradham Karen D, Casteel Stan W, Thomas David J, Basta Nicholas T
School of Environment and Natural Resources, The Ohio State University, Columbus, OH 43210, United States.
US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH 45224, United States.
Soil Syst. 2018;2(2):1-27. doi: 10.3390/soilsystems2020027.
Arsenic (As) is one of the most widespread, toxic elements in the environment and human activities have resulted in a large number of contaminated areas. However abundant, the potential of As toxicity from exposure to contaminated soils is limited to the fraction that will dissolve in the gastrointestinal system and be absorbed into systemic circulation or bioavailable species. In part, the release of As from contaminated soil to gastrointestinal fluid depends on the form of solid phase As also termed "As speciation." In this study, 27 As-contaminated soils and solid wastes were analyzed using X-ray absorption spectroscopy (XAS) and results were compared to bioavailability values determined using the adult mouse and juvenile swine bioassays. Arsenic bioavailability was lowest for soils that contained large amounts of arsenopyrite and highest for materials that contained large amounts of ferric arsenates. Soil and solid waste type and properties rather than the contamination source had the greatest influence on As speciation. Principal component analysis determined that As(V) adsorbed and ferric arsenates were the dominant species that control As speciation in the selected materials. Multiple linear regression (MLR) was used to determine the ability of As speciation to predict bioavailability. Arsenic speciation was predictive of 27% and 16% of RBA As determined using the juvenile swine and adult mouse models, respectively. Arsenic speciation can provide a conservative estimate of RBA As using MLR for the juvenile swine and adult mouse bioassays at 55% and 53%, respectively.
砷（As）是环境中分布最广的有毒元素之一，人类活动已导致大量污染区域。然而，尽管含量丰富，但接触受污染土壤产生的砷毒性潜力仅限于会溶解在胃肠道系统并被吸收进入体循环或生物可利用形态的部分。部分而言，砷从受污染土壤释放到胃肠液中取决于固相砷的形态，也称为“砷形态分析”。在本研究中，使用X射线吸收光谱法（XAS）分析了27种受砷污染的土壤和固体废物，并将结果与使用成年小鼠和幼年猪生物测定法确定的生物可利用性值进行了比较。对于含有大量毒砂的土壤，砷的生物可利用性最低，而对于含有大量砷酸铁的材料，砷的生物可利用性最高。土壤和固体废物的类型及性质而非污染源对砷形态的影响最大。主成分分析确定，吸附的五价砷和砷酸铁是控制所选材料中砷形态的主要物种。使用多元线性回归（MLR）来确定砷形态预测生物可利用性的能力。砷形态分别预测了使用幼年猪和成年小鼠模型测定的相对生物可利用性砷的27%和16%。对于幼年猪和成年小鼠生物测定，砷形态分别可以使用MLR提供相对生物可利用性砷的保守估计值，分别为55%和53%。
