State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China; School of Environment, Nanjing Normal University, Nanjing 210023, PR China.
Water Res. 2021 Oct 1;204:117597. doi: 10.1016/j.watres.2021.117597. Epub 2021 Aug 26.
In recent years, great efforts have been made to understand the capacity of microplastics to adsorb environmental pollutants; however, relatively little is known about the ability of microplastics to release inherent additives into peripheral environments. In this study, we investigated the leaching behavior of phthalate plasticizer from polyvinyl chloride (PVC) microplastics, in aqueous solutions relevant to aquatic and soil environments. It was found that plastic properties, such as particle size, plasticizer content and aging of plastics had a great effect on the leaching of dibutyl phthalate (DnBP). Phthalate release was generally higher in smaller particles and particles with higher phthalate content. Whereas, plastic aging caused by solar irradiation could either enhance phthalate release by increasing plastic hydrophilicity or decrease the leaching by reducing readily available fractions of phthalate. Regarding environmental factors, solution pH (3-9) and ionic strength (0-0.2 M NaCl) were found to have minor effect on phthalate release, while fulvic acid (0-200 mg/L) greatly promoted the release by improving phthalate solubility and solution-plastic affinity. Interestingly, we found that more DnBP was leached out when fulvic acid and NaCl coexisted, and the results from dissolved organic carbon (DOC) and three-dimensional fluorescence spectroscopy analyzes suggested that the leaching of other fulvic acid-like additives might have played a role. These findings would be helpful for predicting the potential of microplastics to release toxic additives under different environmental conditions.
近年来，人们在理解微塑料吸附环境污染物的能力方面做出了巨大努力；然而，对于微塑料将固有添加剂释放到周围环境中的能力，人们知之甚少。在这项研究中，我们研究了聚氯乙烯 (PVC) 微塑料中邻苯二甲酸酯增塑剂在与水相和土壤环境相关的水溶液中的浸出行为。结果表明，塑料特性，如粒径、增塑剂含量和塑料老化，对邻苯二甲酸二丁酯 (DnBP) 的浸出有很大影响。较小的颗粒和增塑剂含量较高的颗粒中邻苯二甲酸酯的释放通常更高。然而，由于太阳辐射引起的塑料老化，通过增加塑料亲水性，或者通过减少邻苯二甲酸酯的易获得部分，可能会增强邻苯二甲酸酯的释放。关于环境因素，发现溶液 pH 值（3-9）和离子强度（0-0.2 M NaCl）对邻苯二甲酸酯的释放影响较小，而腐殖酸（0-200 mg/L）通过提高邻苯二甲酸酯的溶解度和溶液-塑料亲和力，大大促进了邻苯二甲酸酯的释放。有趣的是，我们发现当腐殖酸和 NaCl 共存时，会有更多的 DnBP 浸出，并且来自溶解有机碳 (DOC) 和三维荧光光谱分析的结果表明，其他腐殖酸类添加剂的浸出可能起了作用。这些发现有助于预测微塑料在不同环境条件下释放有毒添加剂的潜力。
