Development of an in vitro digestion model for estimating the bioaccessibility of soil contaminants
Development of an in vitro digestion model for estimating the bioaccessibility of soil contaminants
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DOI：
10.1007/s00244-002-1278-0
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发表时间：
2003-04-01
影响因子：
4
通讯作者：
Sips, AJAM
中科院分区：
文献类型：
--
作者：
Oomen, AG;Rompelberg, CJM;Sips, AJAM
土壤摄入可能是人类接触许多固定土壤污染物的主要途径。目前的风险评估是基于毒性研究，其中污染物通常以液体或食物基质的形式摄入。污染物在土壤基质中摄取的生物利用度差异未被考虑在内。为了成为生物可利用性，污染物首先需要成为生物可及性，即它们必须在消化过程中从土壤中被动员起来。土壤污染物的生物可及性可能低于液体或食物中的污染物，因此风险可能被高估。本文描述了一种基于生理的体外人体消化模型的发展。它可以作为一种评估生物可及性的工具。我们解释了模型实验设计背后的基本原理。我们解决了胃肠道模拟隔间、温度、土液比、消化液比、运输时间、离心、pH值、混合、成分及其浓度和胆汁等方面的问题。以优化后的体外消化模型为例进行了实验研究。测定了上釉陶片中铅的生物可及性，并与去釉陶片土壤中铅的生物可及性进行了比较。数据表明，陶片中铅的生物可达性（0.3 +/- 0.2%）明显低于无陶片土壤中铅的生物可达性（同一地点为42-66%，同一城镇其他地点为28-73%）。此外，土壤中铅的生物可及性值似乎低于膳食铅的计算生物可及性值（这是根据荷兰风险评估使用的标准和文献吸收数据得出的）。这表明，考虑摄入基质会影响铅的暴露评估。体外消化模型是研究摄取基质对生物可及性影响的一种很有前景的工具。
Soil ingestion can be a major route of human exposure to many immobile soil contaminants. The present risk assessment is based on toxicity studies in which contaminants are typically ingested in liquid or food matrices. The difference in bioavailability of contaminants ingested in a soil matrix is not taken into account. To become bioavailable, contaminants first need to become bioaccessible, i.e., they must be mobilized from the soil during digestion. Soil contaminants may be less bioaccessible than contaminants from liquid or food, so that the risks can be overestimated. This article describes the development of an in vitro human digestion model that is physiologically based. It can be used as a tool to assess bioaccessibility. We explain the rationale behind the experimental design of the model. We address the aspects of the simulated compartments of the gastrointestinal tract, temperature, soil-to-fluid ratio, ratio of digestive juices, transit times, centrifugation, pH values, mixing, constituents and their concentrations, and bile. The optimized in vitro digestion model was applied in a case study. The bioaccessibility of lead in pottery flakes with glazing was determined and compared to the bioaccessibility of lead in the soil from which the pottery flakes were removed. The data indicate that pottery flake lead is considerably less bioaccessible (0.3 +/- 0.2%) than lead in soil without pottery flakes (42-66% at the same site, and 28-73% at other sites in the same town). Furthermore, bioaccessibility values of lead in soil appear to be less than calculated bioaccessibility values for dietary lead (which are based on the criterion used by the Dutch risk assessment and on literature absorption data). This indicates that accounting for the matrix of ingestion can affect the exposure assessment for lead. The in vitro digestion model is a promising tool for studying the effect of the ingestion matrix on bioaccessibility.