School of Environmental Sciences, University of Guelph, Guelph, ON, Canada.
MTE Consultants Inc., Kitchener, ON, Canada.
Sci Total Environ. 2019 Jul 10;673:685-693. doi: 10.1016/j.scitotenv.2019.04.059. Epub 2019 Apr 6.
Frameworks for human health risk assessment often include the opportunity to correct the estimate of exposure for bioavailability, which could be predicted from bioaccessibility. Lead and As are the only metallic elements for which bioavailability and bioaccessibility have been correlated across a spectrum of mineralogy and particle types. The objective of the present study is to correlate in vivo bioavailability with ex vivo bioaccessibility for elevated Ni in soils of ultramafic origin and explore attribution of any variation in this correlation to mineralogical characterization of the Ni. Ultramafic soils were field collected in British Columbia, CA. Rietveld quantitative X-ray diffraction was used for the characterization and quantification of crystalline materials containing Ni. Bioaccessible Ni was determined using the in vitro method developed by the Solubility/Bioaccessibility Research Consortium. Bioavailable Ni was determined by gavage dose of the soils to Sprague-Dawley rats. Urine and feces were collected every 24 h. At the end of 72 h, the animals were humanely sacrificed using carbon dioxide as per the approved animal care protocol. All organs were harvested, washed and preserved. Fecal elimination of gavaged Ni ranged from 35 to 95% including positive control. Relative bioavailability (RBA) ranged from 5 to 18%. In vitro bioaccessibility (IVBA) of soil Ni ranged from 0 to 17%; IVBA explained 86% of the variation in RBA. Normalizing both axes to soil olivine accounted for an additional 10% of the variation in RBA. For risk assessment of Ni contaminated soils, IVBA would be a useful and cost effective tool in estimating exposure of mammals through ingestion of soil particles, with some additional benefit of considering Ni mineralogy.
人类健康风险评估框架通常包括校正暴露估计值的机会，该估计值可通过生物可利用度预测。在各种矿物学和颗粒类型中，只有铅和砷的生物利用度和生物可利用度得到了相关。本研究的目的是在超镁铁质起源的土壤中，将体内生物利用度与体外生物可利用度相关联，并探讨这种相关性的任何变化归因于 Ni 的矿物学特征。超镁铁质土壤是在加拿大不列颠哥伦比亚省现场采集的。Rietveld 定量 X 射线衍射用于表征和定量含有 Ni 的结晶物质。使用可溶解性/生物可利用性研究联盟开发的体外方法来确定生物可利用的 Ni。生物有效 Ni 是通过给 Sprague-Dawley 大鼠灌胃土壤来确定的。每隔 24 小时收集一次尿液和粪便。在 72 小时结束时，根据经过批准的动物护理方案，使用二氧化碳对动物进行人道安乐死。所有器官均被采集、清洗和保存。灌胃 Ni 的粪便排泄率为 35%至 95%，包括阳性对照。相对生物利用度（RBA）为 5%至 18%。土壤 Ni 的体外生物可利用度（IVBA）为 0%至 17%；IVBA 解释了 RBA 变化的 86%。将两个轴归一化为土壤橄榄石，额外解释了 RBA 变化的 10%。对于 Ni 污染土壤的风险评估，IVBA 将是一种有用且具有成本效益的工具，可通过摄入土壤颗粒来估计哺乳动物的暴露量，同时考虑 Ni 矿物学还会带来一些额外的好处。
