The calculation of a species sensitivity distribution (SSD) is a commonly accepted approach to derive the predicted no‐effect concentration (PNEC) of a substance in the context of environmental risk assessment. The SSD approach usually is data demanding and incorporates a large number of ecotoxicological values from different experimental studies. The probabilistic SSD (PSSD) approach is able to fully consider the variability between different exposure conditions and material types, which is of great importance when constructing an SSD for any chemical, especially for nanomaterials. The aim of our work was to further develop the PSSD approach by implementing methods to better consider the uncertainty and variability of the input data. We incorporated probabilistic elements to consider the uncertainty associated with uncertainty factors by using probability distributions instead of single values. The new PSSD method (named “PSSD+”) computes 10 000 PSSDs based on a Monte Carlo routine. For each PSSD calculated, the hazardous concentration for 5% of species (HC₅) was extracted to provide a PNEC distribution based on all data available and their associated uncertainty. The PSSD+ approach also includes the option to consider a species weighting according to a typically constituted biome. We applied this PSSD+ approach to a previously published data set on C nanotubes and Ag nanoparticles. The evaluation of the uncertainty factor distributions and species weighting have shown that the proposed PSSD method is robust with respect to the calculation of the PNEC value. Furthermore, we demonstrated that the PSSD+ can handle both small and more comprehensive data sets because the PNEC distributions are a close representation of the data available. Finally, the sensitivity testing toward data set variations showed that the maximum variation of the mean PNEC was of a factor of about 2, so that the method is relatively insensitive to missing data points as long as the most sensitive species is included. Integr Environ Assess Manag 2020;16:211–222. © 2019 SETAC

中文翻译：

---

概率物种敏感性分布中参数不确定性和可变性的系统考虑。

物种敏感度分布（SSD）的计算是在环境风险评估的背景下得出物质的预测无效应浓度（PNEC）的公认方法。SSD方法通常需要数据，并结合了来自不同实验研究的大量生态毒理学价值。概率SSD（PSSD）方法能够充分考虑不同暴露条件和材料类型之间的差异，这对于为任何化学品（尤其是纳米材料）构建SSD至关重要。我们的工作目的是通过实施更好地考虑输入数据的不确定性和可变性的方法来进一步开发PSSD方法。我们结合了概率元素，通过使用概率分布而不是单个值来考虑与不确定性因素相关的不确定性。新的PSSD方法（名为“ PSSD +”）基于蒙特卡洛例程计算了10000个PSSD。对于每个计算出的PSSD，有害物质的浓度为5％（HC₅根据所有可用数据及其关联的不确定性提取），以提供PNEC分布。PSSD +方法还包括根据典型组成的生物群系考虑物种权重的选项。我们将此PSSD +方法应用于先前发布的有关碳纳米管和银纳米颗粒的数据集。对不确定因素分布和物种加权的评估表明，所提出的PSSD方法相对于PNEC值的计算是可靠的。此外，我们证明PSSD +可以处理较小和更全面的数据集，因为PNEC分布是可用数据的近似表示。最后，对数据集变化的敏感性测试表明，平均PNEC的最大变化约为2倍。Integr环境评估管理2020； 16：211–222。©2019 SETAC