Department of Chemical and Biomolecular Engineering, Universidad de Cantabria, Spain.
Department of Chemical and Biomolecular Engineering, Universidad de Cantabria, Spain.
Chemosphere. 2021 Mar;267:129181. doi: 10.1016/j.chemosphere.2020.129181. Epub 2020 Dec 2.
The bioaccessibility of metal(loid)s in ambient particulate matter (PM) has been recently used to represent the risk of inhalation exposure. Nevertheless, different methodological factors affect the bioaccessibility values; among these, the type and composition of surrogate biological fluids and the liquid to solid ratio have been revealed to be the most important. To better understand how these methodological aspects affect the bioaccessibility, a reference material corresponding to urban dust (SRM1648a) was contacted with synthetic biological fluids commonly used in the literature representing surrogate fluids that may interact with fine (Gamble's solutions, artificial lysosomal fluid (ALF)) and coarse particles (gastric fluid), for liquid to solid (L/S) ratios ranging from 500 to 20,000. Visual MINTEQ 3.1. was used to enhance the discussion on how the solubility of metals in the leaching solution depends on the composition of the simulated fluids and the speciation of metals. The results obtained indicate that a small change in the composition of Gamble's solution (the presence of glycine) may increase significantly the bioaccessibility at a L/S ratio of 5,000. The highest bioaccessibility of most of the studied metal(loid)s at a L/S ratio of 5,000 was found for ALF fluid. The study of the effect of the L/S ratio showed that metal(loid)s bioaccessibility in Gamble's fluid increased logarithmically with increasing L/S ratio, while it remained practically constant in ALF and gastric fluid. This different behavior is explained assuming that the leaching of metal(loid)s in Gamble's solution is solubility-controlled, while in ALF and gastric fluid is availability-controlled.
金属（类）在环境颗粒物（PM）中的生物可给性最近被用来表示吸入暴露的风险。然而，不同的方法因素会影响生物可给性值；其中，替代生物流体的类型和组成以及液固比被证明是最重要的。为了更好地了解这些方法方面如何影响生物可给性，用与城市灰尘（SRM1648a）接触的参考物质，用文献中常用的合成生物流体代表可能与细颗粒（甘保尔溶液、人工溶酶体液（ALF））和粗颗粒（胃液）相互作用的替代液，液固比范围从 500 到 20000。使用 Visual MINTEQ 3.1 来增强对金属在浸出溶液中的溶解度如何取决于模拟液组成和金属形态的讨论。结果表明，甘保尔溶液组成的微小变化（甘氨酸的存在）可能会在液固比为 5000 时显著增加生物可给性。在液固比为 5000 时，大多数研究的金属（类）的最高生物可给性是在 ALF 流体中发现的。研究液固比的影响表明，甘保尔溶液中金属（类）的生物可给性随液固比的增加呈对数增加，而在 ALF 和胃液中则基本保持不变。这种不同的行为可以通过假设在甘保尔溶液中金属（类）的浸出是由溶解度控制的，而在 ALF 和胃液中是由可用性控制的来解释。
