Laboratório de Microcontaminantes Orgânicos e Ecotoxicologia Aquática -, Instituto de Oceanografia -, Universidade Federal do Rio Grande (FURG). Caixa Postal 474, CEP: 96203-900, - Rio Grande, RS, Brazil.
Laboratório de Microcontaminantes Orgânicos e Ecotoxicologia Aquática -, Instituto de Oceanografia -, Universidade Federal do Rio Grande (FURG). Caixa Postal 474, CEP: 96203-900, - Rio Grande, RS, Brazil.
Mar Pollut Bull. 2024 Oct;207:116854. doi: 10.1016/j.marpolbul.2024.116854. Epub 2024 Aug 15.
This study investigated the impact of ocean acidification on the photodegradation of three microplastics (MPs): polypropylene (PP), expanded polystyrene (EPS), and ethylene-vinyl acetate (EVA), under accelerated UV radiation at three pH levels (i.e., 8.1, 7.8, and 7.5), simulating marine conditions. The acidification system simulated current and projected future environmental conditions. As expected, an increase in partial pressure of CO2, total inorganic carbon, bicarbonate ion, and CO2 resulted in more acidic pH levels, with the reverse being true for the carbonate ion. Structural changes of MPs were evaluated, revealing that all weathered samples underwent higher degradation rate compared to the virgin samples. The oxidation state and crystallinity of PP and EVA MPs were higher in samples exposed to the lowest pH, whereas no significant increase in the degradation rate of EPS samples was observed. Saltwater acidification in this study contributed to enhance the photo-oxidation of MPs depending on their polymeric composition.
本研究考察了在三种 pH 值（即 8.1、7.8 和 7.5）下，加速 UV 辐射下海洋酸化对三种微塑料（MPs）：聚丙烯（PP）、膨胀聚苯乙烯（EPS）和乙烯-醋酸乙烯酯（EVA）的光降解的影响，模拟海洋环境。酸化系统模拟了当前和未来的环境条件。正如预期的那样，二氧化碳分压、总无机碳、碳酸氢根离子和二氧化碳的增加导致 pH 值更低，而碳酸根离子则相反。评估了 MPs 的结构变化，结果表明，所有风化的样品比原始样品经历了更高的降解速率。在暴露于最低 pH 值的样品中，PP 和 EVA MPs 的氧化态和结晶度较高，而 EPS 样品的降解速率没有明显增加。本研究中的海水酸化有助于根据聚合物组成增强 MPs 的光氧化。
