Paustenbach D J, Bruce G M, Chrostowski P
ChemRisk, Alameda, California 94501, USA.
Risk Anal. 1997 Oct;17(5):533-44. doi: 10.1111/j.1539-6924.1997.tb00895.x.
Due to the presence of mercury at a number of major contaminated sites in the United States, the bioavailability of inorganic mercury in soil following ingestion has emerged as an important public health issue. Studies of the leachability/solubility of inorganic mercury in soil have shown that it is largely immobile, thereby suggesting that it will not be readily available for absorption in the gastrointestinal tract. Ignoring the effect of the soil matrix on decreasing bioavailability may result in a substantial overprediction of risks due to ingestion of contaminated soil. This paper discusses current knowledge about the oral bioavailability of inorganic mercury in soil and offers suggestions about how these data may be applied in human health risk assessment. Though precise estimates are not available, in vivo and in vitro estimates of the bioavailability of different inorganic mercury species in different matrices suggest that the bioavailability of mercury in soil is likely to be significantly less, on the order of at least three- to tenfold, than the bioavailability of mercuric chloride, the species used to derive the toxicity criteria for inorganic mercury. Because bioavailability can vary significantly with soil type, soil aging, the presence of co-contaminants and other factors, it is suggested that whenever the fiscal aspects justify a more precise estimate of bioavailability, site-specific estimates be developed. To develop a database for identifying a less expensive and more efficient method for estimating bioavailability, it is suggested that in vivo studies be conducted concurrently with in vitro studies. However, due to the lack of precision associated with the derivation of the most widely-used health guidance value for inorganic mercury (the USEPA RfD), additional work to address the uncertainties in the RfD is recommended.
由于美国多个主要污染场地存在汞，土壤中无机汞经口摄入后的生物可利用性已成为一个重要的公共卫生问题。对土壤中无机汞的浸出性/溶解性研究表明，它在很大程度上是不移动的，因此表明它在胃肠道中不易被吸收。忽视土壤基质对降低生物可利用性的影响，可能会因摄入受污染土壤而导致对风险的大幅高估。本文讨论了关于土壤中无机汞经口生物可利用性的现有知识，并就如何将这些数据应用于人类健康风险评估提出了建议。尽管无法获得精确估计值，但对不同基质中不同无机汞物种生物可利用性的体内和体外估计表明，土壤中汞的生物可利用性可能比用于推导无机汞毒性标准的氯化汞的生物可利用性显著更低，至少低三到十倍。由于生物可利用性会因土壤类型、土壤老化、共存污染物的存在及其他因素而有显著差异，建议只要财政方面允许对生物可利用性进行更精确的估计，就应开展特定场地的估计。为建立一个数据库以确定一种更便宜、更有效的生物可利用性估计方法，建议同时进行体内研究和体外研究。然而，由于用于推导无机汞最广泛使用的健康指导值（美国环保署参考剂量）缺乏精确性，建议开展更多工作以解决参考剂量中的不确定性问题。
