Biomarkers of exposure: a case study with inorganic arsenic.
Biomarkers of exposure: a case study with inorganic arsenic.
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DOI：
10.1289/ehp.9058
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发表时间：
2006-11
影响因子：
10.4
通讯作者：
Hughes, Michael F
中科院分区：
文献类型：
--
作者：
Hughes, Michael F
环境污染物无机砷（iAs）是一种人体毒物和致癌物。大多数哺乳动物通过将iAs还原为三价，然后氧化甲基化为五价来代谢iAs。iAs及其甲基化代谢物主要在4-5天内由大多数物种经尿液排泄，生物蓄积率相对较低。在甲基化的iAs的个体内和个体间的差异可能会影响砷的不良健康影响。无机和有机三价砷都是比五价砷更强的毒物。已经提出了几种砷致毒性的作用机制，但尚未达成科学共识。暴露的生物标志物可用于量化iAs暴露。最常见的iAs暴露生物标志物是尿总砷的测量。然而，食用含有高浓度有机砷的海产品可能会混淆对iAs暴露的估计。由于这些有机物质被认为是相对无毒的，它们在尿液中的存在可能并不代表风险增加。尿砷的无机和有机形态，甚至氧化态的形态，提供了一个更明确的指示暴露于砷。然而，问题仍然存在，如何可靠地测量尿砷，无论是总的或物种，可以预测砷浓度在靶组织，以及如何测量可以用来评估慢性暴露于iAs。
The environmental contaminant inorganic arsenic (iAs) is a human toxicant and carcinogen. Most mammals metabolize iAs by reducing it to trivalency, followed by oxidative methylation to pentavalency. iAs and its methylated metabolites are primarily excreted in urine within 4–5 days by most species and have a relatively low rate of bioaccumulation. Intra- and interindividual differences in the methylation of iAs may affect the adverse health effects of arsenic. Both inorganic and organic trivalent arsenicals are more potent toxicants than pentavalent forms. Several mechanisms of action have been proposed for arsenic-induced toxicity, but a scientific consensus has not been achieved. Biomarkers of exposure may be used to quantify exposure to iAs. The most common biomarker of exposure for iAs is the measurement of total urinary arsenic. However, consumption of seafood containing high concentrations of organic arsenic can confound estimation of iAs exposure. Because these organic species are thought to be relatively nontoxic, their presence in urine may not represent increased risk. Speciation of urinary arsenic into inorganic and organic forms, and even oxidation state, gives a more definitive indication of the exposure to iAs. Questions still remain, however, as to how reliably the measurement of urinary arsenic, either total or speciated, may predict arsenic concentrations at target tissues as well as how this measurement could be used to assess chronic exposures to iAs.