Toxicology and Environmental Research and Consulting, The Dow Chemical Company, 1803 Building, Midland, MI 48674, USA.
Int J Environ Res Public Health. 2011 Jun;8(6):2212-25. doi: 10.3390/ijerph8062212. Epub 2011 Jun 16.
Due to the vast number of possible combinations of chemicals to which individuals are exposed and the resource-intensive nature of cumulative risk assessments, there is a need to determine when cumulative assessments are most required. This paper proposes the use of the maximum cumulative ratio (MCR) as a tool for this evaluation. MCR is the ratio of the cumulative toxicity received by an individual from exposure to multiple chemical stressors to the largest toxicity from a single chemical stressor. The MCR is a quantitative measure of the difference in an individual's toxicity estimated using a chemical-by-chemical approach and using an additive model of toxicity. As such, it provides a conservative estimate of the degree to which individuals' toxicities could be underestimated by not performing a cumulative risk assessment. In an example application, MCR is shown to be applicable to the evaluation of cumulative exposures involving up to 81 compounds and to provide key insights into the cumulative effects posed by exposures to multiple chemicals. In this example, MCR values suggest that individuals exposed to combinations of chemicals with the largest Hazard Indices were dominated by the contributions of one or two compounds.
由于个体接触的化学物质组合数量众多，且累积风险评估具有资源密集型特点，因此需要确定何时最需要进行累积评估。本文提出使用最大累积比（MCR）作为评估工具。MCR 是个体从接触多种化学胁迫源中所受到的累积毒性与单一化学胁迫源最大毒性的比值。MCR 是一种定量衡量个体毒性的指标，使用化学物质逐个评估方法和毒性相加模型进行估计。因此，它保守地估计了不进行累积风险评估可能导致个体毒性被低估的程度。在一个示例应用中，MCR 适用于评估涉及多达 81 种化合物的累积暴露，并为评估多种化学物质暴露的累积效应提供了关键见解。在这个示例中，MCR 值表明，接触危害指数最大的化学物质组合的个体受到一种或两种化合物的影响较大。
