College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China.
Zhoushan Institute for Food and Drug Control, Zhoushan, 316021, China.
Environ Sci Pollut Res Int. 2020 Nov;27(33):42082-42091. doi: 10.1007/s11356-020-10136-0. Epub 2020 Jul 24.
The pollution of contaminants brought by plastic fragments is worth paying attention in the study of microplastic. The additives, like phthalates (PAEs), introduced during manufacture, are physically dispersed and can easily release into environment. Polyvinyl chloride pipes are widely used in China, and DBP is also a typical kind of additives in PVC materials. Here, the release behavior of DBP from PVC plastic pipe fragments was investigated in water environment under different conditions. Low-density polyethylene (LDPE) passive sampler was used to monitor the contents of DBP. The curve of DBP concentration started from the first increasing stage until a short equilibrium after 45 days' incubation followed by a second increasing part. The release kinetics and the rate-limiting step were discussed. For the whole migration period, the release process was better fitted to pseudo-second order which was participated by both intraparticle and plastic-water film diffusion processes while the two separated parts had different results. Moreover, light, smaller fragments, and higher temperature could all accelerate the release rate and increase the migration amount of DBP. The effect of temperature was the most significant of all, and higher temperature showed more significant effects. Besides, DBP tended to migrate in a long-time continuously. However, the release of additives will be promoted by various physical and chemical processes in nature compared to laboratory tests. Consequently, microplastic (plastic fragments with sizes smaller than 5 mm) with additives acts as a vector for pollutants, and will bring more threat to both environment and organisms.
在微塑料的研究中，值得关注的是塑料碎片带来的污染物污染。在制造过程中引入的添加剂，如邻苯二甲酸酯（PAEs），会被物理分散，并容易释放到环境中。聚氯乙烯管道在中国被广泛使用，而邻苯二甲酸二丁酯（DBP）也是 PVC 材料中典型的添加剂之一。在这里，研究了在不同条件下水环境中 PVC 塑料管道碎片中 DBP 的释放行为。使用低密度聚乙烯（LDPE）被动采样器监测 DBP 的含量。DBP 浓度曲线从第一个增长阶段开始，在 45 天孵育后短暂达到平衡，然后进入第二个增长阶段。讨论了释放动力学和限速步骤。在整个迁移期间，释放过程更符合伪二级动力学，这是由颗粒内扩散和塑料-水膜扩散过程共同参与的，而两个分离的部分有不同的结果。此外，光照、较小的碎片和较高的温度都可以加速释放速率，增加 DBP 的迁移量。温度的影响最为显著，较高的温度显示出更显著的效果。此外，DBP 往往会在长时间内持续迁移。然而，与实验室测试相比，添加剂会促进各种物理和化学过程在自然环境中的释放。因此，含有添加剂的微塑料（尺寸小于 5 毫米的塑料碎片）作为污染物的载体，将对环境和生物带来更大的威胁。
