van der Voet Hilko, Slob Wout
Wageningen UR, Biometris and RIKILT Institute of Food Safety, Wageningen, The Netherlands.
Risk Anal. 2007 Apr;27(2):351-71. doi: 10.1111/j.1539-6924.2007.00887.x.
A method is proposed for integrated probabilistic risk assessment where exposure assessment and hazard characterization are both included in a probabilistic way. The aim is to specify the probability that a random individual from a defined (sub)population will have an exposure high enough to cause a particular health effect of a predefined magnitude, the critical effect size (CES). The exposure level that results in exactly that CES in a particular person is that person's individual critical effect dose (ICED). Individuals in a population typically show variation, both in their individual exposure (IEXP) and in their ICED. Both the variation in IEXP and the variation in ICED are quantified in the form of probability distributions. Assuming independence between both distributions, they are combined (by Monte Carlo) into a distribution of the individual margin of exposure (IMoE). The proportion of the IMoE distribution below unity is the probability of critical exposure (PoCE) in the particular (sub)population. Uncertainties involved in the overall risk assessment (i.e., both regarding exposure and effect assessment) are quantified using Monte Carlo and bootstrap methods. This results in an uncertainty distribution for any statistic of interest, such as the probability of critical exposure (PoCE). The method is illustrated based on data for the case of dietary exposure to the organophosphate acephate. We present plots that concisely summarize the probabilistic results, retaining the distinction between variability and uncertainty. We show how the relative contributions from the various sources of uncertainty involved may be quantified.
提出了一种综合概率风险评估方法，其中暴露评估和危害表征均以概率方式纳入。目的是确定来自特定（亚）人群的随机个体暴露水平高到足以导致预定义程度的特定健康效应（即临界效应大小，CES）的概率。在特定个体中导致恰好该CES的暴露水平是该个体的个体临界效应剂量（ICED）。人群中的个体通常在其个体暴露（IEXP）和ICED方面都表现出变异性。IEXP的变异性和ICED的变异性均以概率分布的形式进行量化。假设两个分布相互独立，它们（通过蒙特卡罗方法）合并为个体暴露边际（IMoE）的分布。IMoE分布中小于1的比例是特定（亚）人群中临界暴露概率（PoCE）。使用蒙特卡罗方法和自助法对总体风险评估中涉及的不确定性（即关于暴露和效应评估的不确定性）进行量化。这会得出任何感兴趣统计量的不确定性分布，例如临界暴露概率（PoCE）。基于饮食中有机磷乙酰甲胺磷暴露情况的数据对该方法进行了说明。我们展示了简洁总结概率结果的图表，保留了变异性和不确定性之间的区别。我们展示了如何量化所涉及的各种不确定性来源的相对贡献。
