Dipartimento di Agraria, University of Sassari, Viale Italia 39/B, 07100 Sassari, Italy.
Future Industries Institute, University of South Australia, Mawson Lakes Campus, Adelaide, SA 5095, Australia.
Sci Total Environ. 2021 May 20;770:145354. doi: 10.1016/j.scitotenv.2021.145354. Epub 2021 Jan 24.
The effect of long-term ageing (up to 700 days) on the mobility, potential bioavailability and bioaccessibility of antimony (Sb) was investigated in two soils (S1: pH 8.2; S2: pH 4.9) spiked with two Sb concentrations (100 and 1000 mg·kg). The Sb mobility decreased with ageing as highlighted by sequential extraction, while its residual fraction significantly increased. The concentration of Sb (C), as determined by diffusive gradients in thin films (DGT), showed a reduction in potential contaminant bioavailability during ageing. The DGT analysis also showed that Sb-C after 700 days ageing was significantly higher in S1-1000 compared to S2-1000, suggesting soil pH plays a key role in Sb potential bioavailability. In-vitro tests also revealed that Sb bioaccessibility (and Hazard Quotient) decreased over time. Linear combination fitting of Sb K-edge XANES derivative spectra showed, as a general trend, an increase in Sb(V) sorption to inorganic oxides with ageing as well as Sb(V) bound to organic matter (e.g. up to 27 and 37% respectively for S2-100). The results indicated that ageing can alleviate Sb ecotoxicity in soil and that the effectiveness of such processes can be increased at acidic pH. However, substantial risks due to Sb mobility, potential bioavailability and bioaccessibility remained in contaminated soils even after 700 days ageing.
研究了在两种土壤（S1：pH 8.2；S2：pH 4.9）中添加两种锑浓度（100 和 1000 mg·kg）下，长期老化（长达 700 天）对锑（Sb）的迁移性、潜在生物可利用性和生物有效性的影响。顺序提取表明，随着老化的进行，Sb 的迁移性降低，而其残留部分显著增加。通过薄膜扩散梯度（DGT）测定的 Sb 浓度（C）表明，老化过程中潜在污染物的生物可利用性降低。DGT 分析还表明，与 S2-1000 相比，S1-1000 中 700 天后的 Sb-C 明显更高，表明土壤 pH 值在 Sb 的潜在生物可利用性中起着关键作用。体外测试还表明，Sb 的生物有效性（和危害系数）随时间降低。Sb K 边 XANES 导数光谱的线性组合拟合表明，作为一般趋势，随着老化的进行，Sb(V)对无机氧化物的吸附以及 Sb(V)与有机物的结合（例如，对于 S2-100，分别增加了 27%和 37%）。结果表明，老化可以减轻土壤中 Sb 的生态毒性，并且在酸性 pH 值下可以提高这些过程的有效性。然而，即使在 700 天后老化，污染土壤中 Sb 的迁移性、潜在生物可利用性和生物有效性仍存在重大风险。
