Austin S G, Sielken R L
Austin Health Consultants, Inc, Fort Collins, CO 80525.
J Occup Med. 1988 Mar;30(3):236-45.
Characterization of the health risks associated with occupational and environmental exposure to ethylene oxide (a gaseous sterilization agent and chemical building block) is made difficult by the limited dose-response information contained in the few published epidemiologic studies available, and the absence of toxicologic data for chronic exposures in species other than the rat. Federal regulatory agencies have relied heavily on conventional quantitative risk assessment techniques in setting revised occupational exposure standards for ethylene oxide. This paper indicates the variability in risk assessment results that can be obtained using the multistage dose-response model and a single animal study depending on the method used to characterize risk, the health endpoint selected, the use of confidence intervals, and the method used to equate animal and human exposure levels. Selection of the most pessimistic options available in each of these four areas is shown to result in a virtually safe dose being characterized as 0.005 ppb, whereas other reasonable assumptions yield a safe dose estimate of 1.3 ppm.
由于现有少数已发表的流行病学研究中包含的剂量反应信息有限，且缺乏除大鼠以外其他物种慢性暴露的毒理学数据，因此对与职业和环境接触环氧乙烷（一种气体消毒剂和化学原料）相关的健康风险进行特征描述变得困难。联邦监管机构在制定环氧乙烷的修订职业接触标准时，严重依赖传统的定量风险评估技术。本文指出，根据用于描述风险的方法、所选的健康终点、置信区间的使用以及用于使动物和人类接触水平相等的方法，使用多阶段剂量反应模型和单一动物研究可获得的风险评估结果存在差异。结果表明，在这四个领域中选择最悲观的选项会导致实际上安全的剂量被描述为0.005 ppb，而其他合理假设得出的安全剂量估计为1.3 ppm。
