Assessment of oral bioaccessibility of organochlorine pesticides in soil using an in vitro gastrointestinal model.
Assessment of oral bioaccessibility of organochlorine pesticides in soil using an in vitro gastrointestinal model.
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DOI：
10.1021/es900188c
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发表时间：
2009-05
影响因子：
11.4
通讯作者：
S. Tao;Yan Lu;Diyu Zhang;Yifeng Yang;Yu Yang;Xiaoxia Lu;D. Sai
中科院分区：
文献类型：
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作者：
S. Tao;Yan Lu;Diyu Zhang;Yifeng Yang;Yu Yang;Xiaoxia Lu;D. Sai
采用静态胃肠道模型研究了不同有机质含量污染土壤中有机氯农药（HCHs和DCPs）及其代谢产物的生物可利用性。测试的一个关键假设是，一部分移动的污染物在消化后吸附在固体上，并且由于小肠吸收溶解的部分，该部分可以解吸并在肠道中变得生物可及。如果在体外试验中通过离心或过滤将吸附部分从流体中分离，则会低估生物可利用性。在我们的实验中，开发了一种使用多个流体-固体比率的程序来表征吸附。结果表明，8-38%的有机氯农药被吸附在残渣上，分离后残留在固相中。考虑到吸附分数，测得的OCPs的生物accessibility变化从4%到97%，这取决于土壤和化合物的属性。研究的手性化合物的对映体比率也被确定，以区分生物（酶）和非生物（化学提取）过程中的体外消化模型。研究发现，尽管未处理土壤中的甲型六氯环己烷是外消旋的，但（+）-甲型六氯环己烷在胃消化液中富集，而在肠消化液中则减少。
A static in vitro gastrointestinal model was used to investigate the oral bioaccessibility of organochlorine pesticides (OCPs) including hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane and metabolites in contaminated soils with different organic matter contents. A key hypothesis tested was that a fraction of the mobilized contaminants is sorbed on the solid after digestion, and this fraction could be desorbed and become bioaccessible in the intestinal tract due to absorption of the dissolved fraction by the small intestine. The bioaccessibility would be underestimated if the sorbed fraction was separated from the fluid by centrifugation or filtration in an in vitro test. In our experiment, a procedure using multiple fluid-to-solid ratios was developed to characterize the sorption. It was found that 8-38% of the mobilized OCPs were sorbed on the residue and remained in the solid phase after the separation. Taking into consideration the sorbed fraction, the measured bioaccessibilities of the OCPs varied from 4% to 97% depending on the properties of the soils and the compounds. The enantiomeric ratios of chiral compounds studied were also determined to distinguish biotic (enzymatic) and abiotic (chemical extraction) processes in the in vitro digestion model. It was found that although alpha-HCH in the raw soils was racemic, (+)-alpha-HCH was enriched in the gastric digestive fluid but depleted in the intestinal digestive fluid.