摘要
用二种方法(无机酸和酶混合模拟液及双酸模拟液)模拟研究了胃酸环境下杭州市城市灰尘中铅的生物可给性。研究结果表明,无机酸和酶混合模拟液的溶出量高于双酸模拟液的溶出量。灰尘中铅的生物可给性与胃酸的酸度和灰尘中铅的化学形态有关。灰尘中铅的溶出量随pH的下降而增加,当pH在3．5以上时,溶出量较低；当pH在2．5以下时,铅溶出量随pH的下降而显著增加。不同pH条件下,溶出的铅来自不同的化学形态,交换态和碳酸盐结合态优先溶出,在较低的pH条件下,有机结合态和氧化物结合态铅也可被部分溶出,表明具高比例的交换态和酸可溶态铅的灰尘有较大的潜在毒性。胃酸中磷酸盐的存在可降低铅的溶解,但当pH在2以下时,磷酸盐的作用不明显。在正常饮食的胃酸环境中(pH4～5),灰尘中Pb的溶出比例不高。
The possible human health effects resulting from the ingestion of dust bound lead is a major environmental concern.Understanding the bioaccessibility and chemical forms of lead （Pb） in urban dusts is necessary to predict potential impact of the dust Pb on human heath. In this study, six urban dust samples were collected from Hangzhou city, Zhejiang province, China, and chemical forms in the urban dusts were characterized by a sequential extraction. The samples were also subjected to determination of Pb bioaccessibility using two artificial biofluids. Lead form in the dusts from Hangzhou city was mainly associated with Fe and Mn oxides, organic matters as well as clay minerals. The concentration of exchangeable and carbonate bound Pb in the dusts was low. The Pb bioaccessibility of the urban dusts was related to pH in gastric system and chemical forms of the dusts. Solubility of Pb in the dusts was generally low when pH was above 3.5, and increased significantly with pH when pH was below 2.5. Exchangeable and carbonate bound Pb in the dusts were preferentially dissolved in the gastric system. These results suggested that bioaccessibility of Pb in dusts increased with increasing proportions of exchangeable and carbonate bound forms of Pb. However, in normal gastric condition （pH 4-5）, the bioaccessibility of Pb in the urban dusts was generally low.
出处
《科技通报》
2006年第4期482-486,489,共6页
Bulletin of Science and Technology
基金
国家自然科学基金(40471064)
浙江省自然科学基金(M403038)
关键词
铅
灰尘
化学形态
生物可给性
Lead
urban dust
chemical form
bioaccessibility
