Bruce Scott, Noller Barry, Matanitobua Vitukawalu, Ng Jack
National Research Centre for Environmental Toxicology, University of Queensland, Coopers Plains, Queensland, Australia.
J Toxicol Environ Health A. 2007 Oct;70(19):1700-11. doi: 10.1080/15287390701434901.
In vivo models show that the bioavailability of soil contaminants varies between site and type of matrix. Studies demonstrated that assuming 100% bioavailability of arsenic (As) and lead (Pb) from soils and mine waste materials overestimates the risk associated with human exposure. In in vitro systems, the simulated bioavailability of a contaminant is referred to as the "bioaccessibility" and is used as an alternative quantitative indicator for in vivo derived bioavailability estimates. The general concept of the in vitro extraction test is to predict the bioavailability of inorganic substances from solid matrices by simulating the gastrointestinal tract (GIT) environment. The aims of this study were to: (1) investigate the bioaccessibility of As and Pb from various mine wastes, including tailings, heap leach, and waste rock, using a physiologically based extraction test (PBET); (2) validate the bioaccessibility values from PBET with in vivo bioavailability values measured using animal models; and (3) correlate PBET results with the bioavailability values measured from alternative in vivo models (rats and cattle, from Bruce, 2004). Significant correlation was observed between bioaccessibility values from PBET, and bioavailability values generated for both rats and cattle, demonstrating the potential to utilize PBET as a relatively inexpensive alternative to in vivo models for bioavailability assessment.
体内模型表明，土壤污染物的生物有效性因地点和基质类型而异。研究表明，假设土壤和矿山废料中砷（As）和铅（Pb）的生物有效性为100%会高估与人类接触相关的风险。在体外系统中，污染物的模拟生物有效性被称为“生物可及性”，并被用作体内衍生生物有效性估计的替代定量指标。体外提取试验的总体概念是通过模拟胃肠道（GIT）环境来预测固体基质中无机物质的生物有效性。本研究的目的是：（1）使用基于生理学的提取试验（PBET）研究各种矿山废料（包括尾矿、堆浸物和废石）中As和Pb的生物可及性；（2）用动物模型测量的体内生物有效性值验证PBET的生物可及性值；（3）将PBET结果与从其他体内模型（大鼠和牛，来自Bruce，2004）测量的生物有效性值相关联。观察到PBET的生物可及性值与大鼠和牛产生的生物有效性值之间存在显著相关性，这表明利用PBET作为生物有效性评估的体内模型的相对廉价替代方法具有潜力。
