The distribution of elemental species of chromium (Cr) in potentially-contaminated soil samples warrants investigation due to the differing mobilities and toxicities of trivalent [Cr(III)] and hexavalent chromium [(Cr(VI)]. In addition, the possibility of species interconversions requires the implementation of robust methods that can correct for changes at the point of sampling, extraction and analysis. This work presents the application of speciated isotope dilution mass spectrometry (SIDMS) to accurately quantify Cr(VI) in agricultural soils within close proximity to a mine tailings dam in the Copperbelt Province of Zambia. Interpolated plots of total Cr, produced from data collected through a nested sampling design, were used to optimise the sampling across the spatial domain. Extraction of Cr(VI) was undertaken using a microwave assisted reaction system (80 °C for 5 min) with 50 mM EDTA, to complex Cr(III) and reduce the likelihood of oxidation during the extraction. Isotopically-enriched 53Cr(VI) was added to each sample prior to extraction to account for species interconversions. The accuracy of the method was confirmed using NIST SRM 2700 and 2701. Cr(VI) concentrations in the soil samples ranged between 0.03 and 0.29 mg kg-1, significantly lower than the residential UK screening value for Cr(VI) of 21 mg kg-1. The data indicate that this site poses a low environmental/human health risk with respect to Cr(VI) exposure.

中文翻译：

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赞比亚铜带省的潜在污染农业土壤中的六价铬的勘测采样和测定。

使用微波辅助反应系统（80°C，5分钟）和50 mM EDTA萃取Cr（VI），以络合Cr（III）并降低萃取过程中氧化的可能性。在提取之前，将同位素富集的53Cr（VI）添加到每个样品中，以说明物种之间的相互转化。使用NIST SRM 2700和2701证实了该方法的准确性。土壤样品中的Cr（VI）浓度范围为0.03至0.29 mg kg-1，显着低于英国居民对Cr（VI）的21 mg kg筛选值。 -1。数据表明，该场所对六价铬的暴露对环境/人类健康构成低风险。在提取之前，将同位素富集的53Cr（VI）添加到每个样品中，以说明物种之间的相互转化。使用NIST SRM 2700和2701证实了该方法的准确性。土壤样品中的Cr（VI）浓度范围为0.03至0.29 mg kg-1，显着低于英国居民对21 mg kg Cr（VI）的筛查值。 -1。数据表明，该场所对六价铬的暴露对环境/人类健康构成低风险。在提取之前，将同位素富集的53Cr（VI）添加到每个样品中，以说明物种之间的相互转化。使用NIST SRM 2700和2701证实了该方法的准确性。土壤样品中的Cr（VI）浓度范围为0.03至0.29 mg kg-1，显着低于英国居民对21 mg kg Cr（VI）的筛查值。 -1。数据表明，该场所对六价铬的暴露对环境/人类健康构成低风险。