Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China.
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China.
Environ Pollut. 2022 Mar 1;296:118758. doi: 10.1016/j.envpol.2021.118758. Epub 2021 Dec 27.
Microplastics (MPs) are detected in drinking water and plastic used during water treatment and distribution is one of the possible sources of MPs. This work aimed to investigate the MPs release behavior from ozone-exposed plastic pipe materials. The changes on physicochemical properties of the plastic materials were analyzed. The carbonyl groups introduction, the oxidation induction time variation, and the surface topography altering were detected after ozone exposure. The MPs release behavior varied between different plastic materials. As the ozone exposure duration of plastic materials prolonged, the released MPs abundance from the materials sharply increased, especially for LDPE, HDPE and PP. PVC was an exception where the released MPs abundance had little changes (p > 0.05). The total released MPs concentration from 20 h-aged samples could be ranked in order as follows: LDPE (656 ± 20 MP L) > PP (349 ± 20 MP L) > HDPE (337 ± 22 MP L) > PVC (63 ± 13 MP L). MPs release behavior was more likely to occur for LDPE, which was possibly related to the low oxidation resistance and weak stability of LDPE under ozone exposure. There was a more dominant contribution to MPs abundance increase caused by MPs release from aged plastic pipe materials than secondary MPs generation from original plastic particles. The generated MPs from 20 h-aged LDPE, HDPE, and PP accounted for 88.4%, 82.2%, and 88.3% of the total released MPs, respectively. For ozone-exposed plastic materials, the surface crack propagation and fragmentation posed an entry point for MPs generation. The proportion of generated MPs with polymer composition consistent with pipe materials (PE/PP) increased as the ozone exposure proceeded. Small-sized particles, especially 1-10 μm, were released more predominantly. This study provides an implication that possible MPs release from long-term aged plastic pipe materials under proper conditions could not be ignored.
微塑料（MPs）在饮用水中被检出，而在水处理和分配过程中使用的塑料是 MPs 的可能来源之一。本工作旨在研究臭氧暴露塑料管材材料的 MPs 释放行为。分析了塑料材料理化性质的变化。臭氧暴露后，检测到羰基基团的引入、氧化诱导时间的变化和表面形貌的改变。不同塑料材料的 MPs 释放行为不同。随着塑料材料臭氧暴露时间的延长，材料中释放的 MPs 丰度急剧增加，尤其是 LDPE、HDPE 和 PP。PVC 是一个例外，其释放的 MPs 丰度几乎没有变化（p＞0.05）。从 20 小时老化样品中释放的总 MPs 浓度可按以下顺序排列：LDPE（656±20 MPs L）＞PP（349±20 MPs L）＞HDPE（337±22 MPs L）＞PVC（63±13 MPs L）。LDPE 更有可能发生 MPs 释放行为，这可能与 LDPE 在臭氧暴露下的低抗氧化性和弱稳定性有关。老化塑料管材材料中 MPs 的释放比原始塑料颗粒二次 MPs 的生成对 MPs 丰度增加的贡献更大。从 20 小时老化的 LDPE、HDPE 和 PP 中产生的 MPs 分别占总释放 MPs 的 88.4%、82.2%和 88.3%。对于臭氧暴露的塑料材料，表面裂纹的扩展和破碎为 MPs 生成提供了切入点。随着臭氧暴露的进行，与管材材料（PE/PP）组成一致的生成 MPs 的比例增加。小尺寸颗粒，特别是 1-10 μm 的颗粒，释放得更为突出。本研究表明，在适当条件下，长期老化的塑料管材材料中可能会释放 MPs，这一点不容忽视。
