Matthies Michael, Berding Volker, Beyer Andreas
Institute of Environmental Systems Research, University of Osnabrück, Germany.
Environ Toxicol Chem. 2004 Oct;23(10):2494-502. doi: 10.1897/03-529.
The European Union System for the Evaluation of Substances (EUSES) is a computerized model system to facilitate and harmonize health and environmental risk assessment of previously notified and new substances. For calculation of regional background exposure, a multimedia distribution model is used. In the present study, the uncertainty of this regional model is analyzed. Environmental parameters were collected for North Rhine Westphalia (Germany), which resembles the standard region of EUSES. Probability distribution functions of various types (uniform, triangular, normal, log normal) depending on data availability were derived for environmental input parameters, including geometric parameters. Generic log-normal distribution functions with fixed standard deviations were chosen for solubility in air, water, and n-octanol as well as for degradation half-lives. Monte Carlo simulations were carried out for 10 reference substances having different properties. Contribution of environmental parameter uncertainty to total output uncertainties is higher than that of substance parameters. Range of output uncertainty, defined as the ratio of the logarithms of the 90th and 10th percentiles of the cumulative probability distribution function, shows an increase from air and water to soil. The highest-occurring range is 1.4 orders of magnitude, which means that total uncertainty of the regional model is relatively low and, usually, is lower than the range of measured values. The median of output probability distributions lies above the point estimate. Influence of input parameters was estimated as their rank correlation coefficients to output uncertainty. Substance and environmental parameters contribute differently to output variance depending on individual substance properties and environmental compartment. Hence, the present study underlines the need to perform uncertainty analyses instead of either using a set of simple rules or just looking at certain parameters.
欧盟物质评估系统（EUSES）是一个计算机化模型系统，旨在促进和协调对先前已通报物质和新物质的健康与环境风险评估。为了计算区域背景暴露，使用了一个多介质分布模型。在本研究中，分析了该区域模型的不确定性。收集了德国北莱茵 - 威斯特法伦州的环境参数，该地区类似于EUSES的标准区域。根据数据可用性，为包括几何参数在内的环境输入参数推导了各种类型（均匀、三角、正态、对数正态）的概率分布函数。对于在空气、水和正辛醇中的溶解度以及降解半衰期，选择了具有固定标准差的通用对数正态分布函数。对10种具有不同性质的参考物质进行了蒙特卡罗模拟。环境参数不确定性对总输出不确定性的贡献高于物质参数的贡献。输出不确定性范围定义为累积概率分布函数第90百分位数与第10百分位数对数的比值，从空气和水到土壤呈增加趋势。出现频率最高的范围为1.4个数量级，这意味着区域模型的总不确定性相对较低，通常低于测量值范围。输出概率分布的中位数高于点估计值。输入参数的影响通过它们与输出不确定性的等级相关系数来估计。物质和环境参数对输出方差的贡献因个别物质性质和环境介质而异。因此，本研究强调了进行不确定性分析的必要性，而不是要么使用一组简单规则，要么只关注某些参数。
