Estimation of lead and arsenic bioavailability using a physiologically based extraction test
Estimation of lead and arsenic bioavailability using a physiologically based extraction test
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DOI：
10.1021/es950057z
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发表时间：
1996-02-01
影响因子：
11.4
通讯作者：
Sellstone, CM
中科院分区：
文献类型：
--
作者：
Ruby, MV;Davis, A;Sellstone, CM
基于生理的提取试验(PBET)是一种体外测试系统，用于预测固体基质中金属的生物可利用性，并结合了代表人体的胃肠道参数(包括胃和小肠的pH值和化学、土壤与溶液的比例、胃的混合和胃排空率)。对于铅，PBET的结果与SpragueDawley大鼠模型的结果呈线性相关(r(2)=0.93，体外和体内结果，n=7)。对于砷(AS)，PBET的结果高估了兔和灵长类动物模型的生物利用度研究结果(体外和体内结果相差2-11%，具体取决于动物模型)。PBET的设计并不是为了取代使用动物模型进行的生物利用度研究，而是在没有动物研究结果的情况下估计铅和砷的生物利用度。铅在酸性胃环境中的溶解对pH有很强的依赖性；当胃的pH值从1.3增加到2.5时，铅的溶解程度降低了65%。在相同的pH范围内，砷的溶解度仅下降了16%。在小肠模拟过程中，铅从溶液中的去除程度大于As，这与中性pH值下发生的吸附和沉淀反应一致，但不是As。除了为控制铅和砷的生物有效性提供机械解释外，PBET还允许为暴露评估的目的估计特定地点土壤中的铅和砷的生物有效性。
The physiologically based extraction test (PBET) is an in vitro test system for predicting the bioavailability of metals from a solid matrix and incorporates gastrointestinal tract parameters representative of a human (including stomach and small intestinal pH and chemistry, soil-to-solution ratio, stomach mixing, and stomach emptying rates). For lead (Pb), the results of the PBET are linearly correlated with results from a Sprague-Dawley rat model (r(2) = 0.93 between in vitro and in vivo results, n = 7). For arsenic (As), the results of the PBET are overpredicting bioavailability study results in rabbit and primate models (2-11% difference between in vitro and in vivo results, depending on the animal model). The PBET was not designed to supplant bioavailability studies using animal models, but rather to estimate Pb and As bioavailability when animal study results are not available. Dissolution of Pb in the acidic stomach environment was strongly pH dependent; the extent of dissolution decreased by 65% when stomach pH was increased from 1.3 to 2.5. Arsenic solubility decreased by only 16% over the same pH range. Lead was removed from solution to a greater extent than As by neutralization during the small intestinal simulation, consistent with adsorption and precipitation reactions occurring for Pb-but not As-at neutral pH values. In addition to providing mechanistic explanations for controls on Pb and As bioavailability, the PBET allows estimates of site-specific Pb and As bioavailability from soil for the purpose of exposure assessment.