Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
Instituto Hidrográfico, R. Trinas 49, 1249-093 Lisboa, Portugal.
Environ Sci Technol. 2022 Aug 2;56(15):11080-11090. doi: 10.1021/acs.est.2c01828. Epub 2022 Jul 13.
The quantification and comparison of microplastic contamination of sediments are affected by sample heterogeneity and the systematic and random effects affecting sample analysis. The quantification and combination of these components in the measurement uncertainty allows the objective interpretation of analysis results. This work presents the first detailed evaluation of the uncertainty of microplastic contamination quantification in sediments. The random and systematic effects affecting microplastic counts are modeled by the Poisson-lognormal distribution with inputs estimated from duplicate sediment analysis and the analysis of sediments spiked with microparticles. The uncertainty from particle counting was combined with the uncertainty from the determination of the dry mass of the analytical portion by the Monte Carlo method. The developed methodology was implemented in a user-friendly spreadsheet made available as the Supporting Information. The contamination of sediment samples collected in various inland Portuguese waters was determined, ranging from [0; 160] to [361; 2932] kg for a 99% confidence level, and compared by assessing if the difference between contamination levels is equivalent to zero for the same confidence level. Several samples proved to have metrologically different microplastic contamination. This work represents a contribution to the objectivity of the assessment of environmental contamination with microplastics.
沉积物中微塑料污染的量化和比较受到样品不均匀性以及影响样品分析的系统和随机效应的影响。在测量不确定度中对这些成分进行量化和组合，可实现对分析结果的客观解释。本工作首次详细评估了沉积物中微塑料污染量化的不确定度。通过泊松-对数正态分布对影响微塑料计数的随机和系统效应进行建模，输入值是通过对沉积物重复分析和用微颗粒对沉积物进行加标分析来估算的。通过蒙特卡罗法将颗粒计数的不确定度与分析部分干质量测定的不确定度相结合。开发的方法学已在一个用户友好的电子表格中实施，该电子表格作为支持信息提供。在置信水平为 99%的情况下，测定了在葡萄牙内陆不同水域采集的沉积物样本的污染程度，范围为[0；160]至[361；2932]kg，并通过评估同一置信水平下污染水平的差异是否等于零来进行比较。有几个样本被证明具有不同的微塑料污染。本工作为微塑料对环境污染评估的客观性做出了贡献。
