我国人群胃肠消化环境中土壤Pb的人体可给性

Bioaccessibility of Lead in Soil Based on Chinese Gastrointestinal Digestion Characteristics

当前土壤中污染物人体可给性的体外模拟测试方法主要依据西方人群的胃肠环境制定,为建立能够客观表征土壤中污染物在我国人群胃肠消化环境中的人体可给性测试方法,以铅(Pb)污染土样为对象,采用《中华人民共和国药典:一部》(简称“《药典》”)中记载的我国人群胃肠液组分配置模拟胃肠消化液,对采自广西壮族自治区、辽宁省和湖南省的13个土样中Pb的人体可给性进行研究.结果表明:供试土样中Pb在胃消化阶段的人体可给性平均值为51.9%(范围为0.4%~86.1%),显著高于其在肠消化阶段的人体可给性平均值0.6%(范围为0.0025%~3.1%),与采用国际上常用的UBM(Unified Bioaccessibility Model)方法的测试结果无明显差异,表明我国《药典》中推荐的胃肠液组分能够用于开展土样中Pb的人体可给性测试.研究显示,模拟胃液的pH是影响土样中Pb在胃消化阶段人体可给性测试结果的关键因素,测试过程中pH宜维持在1.0左右,而且,可将《药典》推荐的模拟胃液组分进一步优化为HCl和去离子水,以降低测试成本;模拟肠液应严格按《药典》推荐的组分进行配置,测试体系的pH宜维持在8.0左右.

The currently used bioaccessibility test assays are developed based on the gastrointestinal digestive characteristics of westerners.In this paper,the components of gastric and intestinal juice recommended by the Chinese Pharmacopoeia were used to study the bioaccessibility of Pb in 13 soil samples collected from Dalian,Hunan and Guangxi,aiming to develop a test method to characterize the bioaccessibility of Pb in the digestive tract of Chinese people.The results revealed that the average Pb bioaccessibility in the stomach was 51.9%(0.4%-86.1%),which was much higher than the average value 0.6%(0.0025%-3.1%)in the intestine.No significant difference was observed between the results in this study and those obtained using UBM assay,indicating that the components recommended by the Chinese Pharmacopoeia can be used as simulated gastrointestinal juice to test Pb bioaccessibility in soil.The pH of simulated gastric juice is the key parameter controlling the bioaccessibility of Pb in the stomach,and it should be kept at about 1.0 throughout the experiment.In addition,the components of simulated gastric juice recommended by the Chinese Pharmacopoeia can be further optimized to HCl and deionized water,contributing to the reduction of test cost.The components recommended by the Chinese Pharmacopoeia should be strictly followed when it is used to test the bioaccessibility of Pb in the intestine,and the pH should be kept at around 8.0 throughout the experiment.