采用体外试验与连续提取相结合的方法研究污染土壤中镉的生物可给性。
Coupling in vitro assays with sequential extraction to investigate cadmium bioaccessibility in contaminated soils.
机构信息
School of Water Conservancy and Environment, University of Jinan, Jinan, 250022, China.
School of Water Conservancy and Environment, University of Jinan, Jinan, 250022, China.
出版信息
Chemosphere. 2022 Feb;288(Pt 3):132655. doi: 10.1016/j.chemosphere.2021.132655. Epub 2021 Oct 25.
To understand how Cd in different fractions contributes to Cd bioaccessibility by in vitro assays, Cd bioaccessibility in 12 contaminated soils was determined by four assays (UBM, SBRC, IVG, and PBET) and correlated with different Cd fractions based on a sequential extraction scheme. The Cd bioaccessibility in the gastric phase (GP) was high (35-107%, averaging at 77%), implicating high risk to human health, while it decreased to 19-88% averaging at 47% in the intestinal phased (IP). From the GP to IP, the reduction of extractable Cd (0.45-48 mg kg) and Fe (118-3884 mg kg) showed significant correlation (R = 0.54-0.74) via UBM, SBRC, and IVG, suggesting co-precipitation with Fe and/or sorption onto Fe oxides maybe responsible for decrease in Cd bioaccessibility. Although Cd bioaccessibility varied among assays, their results show some consistency based on their correlation in the GP (R = 0.56-0.90) and IP (0.34-0.73, excluding UBM-IP and PBET-IP). Sequential extraction data show that Cd was primarily associated with the exchangeable fraction (E1; 7.05-72.9%, averaging 39.4%). The carbonate (C2; 6.86-44.8%, 21.9%) and Fe/Mn oxides fraction (F3; 12.5-53.6%, 28.2%) were similar, while organic (O4; 0.62-25.0%, 7.91%) and residual fraction (R5; 0.22-8.54%, 2.62%) were the lowest. Significant correlation (R = 0.59-0.88) between the first two fractions (E1+C2) and bioaccessible Cd suggest they were the main sources of bioaccessible Cd in those contaminated soils.
为了了解不同形态的镉如何通过体外试验影响镉的生物可给性，采用 4 种体外试验（UBM、SBRC、IVG 和 PBET）测定了 12 种污染土壤的镉生物可给性，并根据连续提取方案将其与不同镉形态进行了相关分析。胃相（GP）中的镉生物可给性较高（35%-107%，平均值为 77%），这意味着对人类健康存在高风险，而在肠相（IP）中则降低至 19%-88%，平均值为 47%。从 GP 到 IP，通过 UBM、SBRC 和 IVG，可提取的 Cd（0.45-48mgkg）和 Fe（118-3884mgkg）的减少呈显著相关（R=0.54-0.74），表明与 Fe 的共沉淀和/或与 Fe 氧化物的吸附可能是导致 Cd 生物可给性降低的原因。尽管不同试验中的镉生物可给性存在差异，但它们的结果在 GP（R=0.56-0.90）和 IP（0.34-0.73，UBM-IP 和 PBET-IP 除外）中具有一定的一致性。连续提取数据表明，Cd 主要与可交换态（E1；7.05%-72.9%，平均值为 39.4%）有关。碳酸盐（C2；6.86%-44.8%，21.9%）和铁锰氧化物（F3；12.5%-53.6%，28.2%）的含量相似，而有机（O4；0.62%-25.0%，7.91%）和残渣态（R5；0.22%-8.54%，2.62%）的含量最低。前两个形态（E1+C2）与生物可给性 Cd 之间存在显著相关性（R=0.59-0.88），表明它们是这些污染土壤中生物可给性 Cd 的主要来源。
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