Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, 72076, Tübingen, Germany.
China National Institute of Standardization, Beijing, 100191, China.
Environ Monit Assess. 2024 Oct 14;196(11):1050. doi: 10.1007/s10661-024-13182-0.
Polyethylene (PE) and other polymers are widely and successfully used as passive samplers for organic pollutants in the environment. This study provides high-resolution experimental data from batch shaking tests on the uptake, reversibility, and linear equilibrium partitioning of polycyclic aromatic hydrocarbons (PAHs) using two different PE sheets of 30 µm and 80 µm thickness. Kinetics for phenanthrene are well described by a mechanistic first-order model with mass transfer limited by an aqueous boundary layer (with a mean thickness of 170 µm). Equilibration in laboratory batch systems during uptake and desorption is very rapid with characteristic times of 1-2 h but this depends on the boundary condition, e.g., the ratio of PE mass to water volume. Therefore, equilibration of PE in other setups, e.g., in soil slurries or sediment suspensions, may take orders of magnitude longer because the boundary condition for PE changes from finite to infinite bath conditions (soil or sediment particles may keep the concentration in water almost constant). Solid precipitates for high molecular weight PAHs explain partition coefficients below expected values because of kinetic limitations in such a system. Nevertheless, passive sampling can be employed safely if such limitations are considered; furthermore, partition coefficients can be estimated accurately by empirical relationships (e.g., within 0.1 log unit) based on molecular weight, octanol/water partition coefficients, or subcooled liquid solubilities.
聚乙烯 (PE) 和其他聚合物被广泛且成功地用作环境中有机污染物的被动采样器。本研究提供了使用两种不同厚度（30 µm 和 80 µm）的 PE 片进行批量摇瓶试验中多环芳烃 (PAHs) 吸收、可逆性和线性平衡分配的高分辨率实验数据。菲的动力学很好地用一个具有受水边界层限制的传质的机制一阶模型来描述（具有 170 µm 的平均厚度）。在吸收和解吸过程中，实验室批量系统中的平衡非常迅速，特征时间为 1-2 小时，但这取决于边界条件，例如 PE 质量与水体积的比例。因此，PE 在其他设置中的平衡，例如在土壤泥浆或沉积物悬浮液中，可能需要更长的时间，因为 PE 的边界条件从有限浴条件变为无限浴条件（土壤或沉积物颗粒可能使水中的浓度几乎保持不变）。对于高分子量 PAHs 的固体沉淀物解释了低于预期值的分配系数，因为在这样的体系中存在动力学限制。然而，如果考虑到这些限制，被动采样可以安全地使用；此外，通过基于分子量、辛醇/水分配系数或过冷液体溶解度的经验关系（例如，在 0.1 对数单位内）可以准确估计分配系数。
