Environmental Biogeochemistry, Centro de Química Estrutural, IST-UL, Lisboa, Portugal; IPMA - Instituto Português do Mar e da Atmosfera, Algés, Portugal.
Bioxeoquímica Mariña, Instituto de Investigacións Mariñas IIM-CSIC, Vigo, Spain.
Sci Total Environ. 2020 Jun 20;722:137954. doi: 10.1016/j.scitotenv.2020.137954. Epub 2020 Mar 16.
Road dust is a major reservoir of anthropogenic Pt and Rh. However, information about how these elements are released to the aquatic systems under environmentally relevant conditions is scarce. In this work, an innovative combination of analytical strategies is used to provide insight into the speciation analysis of those elements. A composite sample of road dust thoroughly characterized was incubated over 7 days in synthetic rainwater and seawater. In the filtered (<0.45 μm) solutions, truly dissolved Pt and Rh concentrations were measured by adsorptive cathodic stripping voltammetry, while total concentrations were determined by inductively coupled plasma mass spectrometry. Truly dissolved species corresponded to a small fraction of total Pt and Rh in the road dust; accordingly, values of 0.01% and 0.1% were obtained in both media for Pt and Rh, respectively, which remained constant over time. The concentration of total filter-passing species predominates for both elements by a factor of 10 and 2-3 for Pt and Rh, respectively, evidencing that particulate species coexist with truly dissolved forms. Temporal variations were observed for Pt, as opposed to Rh. These findings contribute to the gap in knowledge regarding Pt and Rh mobility in aquatic systems.
道路灰尘是人为 Pt 和 Rh 的主要储存库。然而，关于这些元素在何种环境条件下释放到水生系统中的信息却很少。在这项工作中，创新性地结合了多种分析策略，用于深入了解这些元素的形态分析。对经过充分表征的道路灰尘进行了复合样本培养，在合成雨水和海水中孵育了 7 天。在过滤（<0.45 μm）溶液中，通过吸附阴极剥离伏安法测量了真正溶解的 Pt 和 Rh 浓度，而总浓度则通过电感耦合等离子体质谱法测定。在道路灰尘中，真正溶解的物质仅占总 Pt 和 Rh 的一小部分；因此，在两种介质中，Pt 和 Rh 的溶解率分别为 0.01%和 0.1%，且随时间保持不变。对于这两种元素，总过滤物种的浓度分别是 Pt 和 Rh 的 10 倍和 2-3 倍，这表明颗粒物质与真正溶解的物质共存。Pt 与 Rh 相反，观察到了时间变化。这些发现有助于填补有关 Pt 和 Rh 在水生系统中迁移性的知识空白。
