Abstract：
The high use of plastic wraps leads to significant environmental pollution. In this study, the surface structure and microbial community evolution of commercially available plastic wraps [polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), and polylactic acid (PLA)] in constructed wetlands (CWs) were investigated. The results indicated that all plastic wraps gradually decreased in molecular weight, crystallinity, melting, and crystallization temperatures, whereas a gradual increase was observed in the surface roughness, polymer dispersity index (PDI), carbonyl index (CI) and Shannon index of microorganisms colonizing the CWs. The aging rate of the plastic wrap was in the order: PLA > PVC > PE > PVDC, at the same site in the CWs, and it was in the order: soil surface > plant roots > subsoil, for the same plastic wrap. The diversity of microorganisms colonizing the same plastic wrap was in the order: plant roots > subsoil > soil surface. The Shannon indices of microorganisms on plastic wraps were lower than those in the soil, indicating that the diversity of microorganisms colonizing plastic wraps is limited. Additionally, the microbial community structure on the plastic surface was co-differentiated by the plastic type, placement position in the CWs, and aging time. Significantly different microbial community structures were found on the PVC and PVDC wrap surfaces, revealing that the chlorine in plastics limits microbial diversity. Unclassified members of Rhizobiaceae and Pseudomonadaceae were the dominant genera on the surface of the plastic wraps, suggesting that they may be the microorganisms involved in plastic degradation processes. The study provides valuable perspectives to facilitate a comprehensive understanding of the migration, fate, and environmental risks associated with microplastics (MPs) in wetlands.
摘要：
大量使用塑料包装会导致严重的环境污染。在这项研究中,市售塑料包装的表面结构和微生物群落演变[聚乙烯(PE)，聚氯乙烯(PVC),聚偏二氯乙烯(PVDC)，和聚乳酸（PLA）]在人工湿地（CWs）中进行了研究。结果表明，所有塑料包装的分子量逐渐降低，结晶度熔化，和结晶温度，而表面粗糙度逐渐增加，聚合物分散指数(PDI)，微生物定殖CW的羰基指数(CI)和Shannon指数。保鲜膜的老化率依次为:PLA>PVC>PE>PVDC,在CW的同一地点，顺序是:土壤表面>植物根>底土，同样的塑料包装。同一保鲜膜定殖的微生物多样性依次为：植物根>底土>土壤表面。塑料包装上的微生物的香农指数低于土壤中的微生物，表明微生物定植塑料包装的多样性是有限的。此外,塑料表面的微生物群落结构被塑料类型共分化，CW中的放置位置，和老化时间。在PVC和PVDC包裹物表面上发现了明显不同的微生物群落结构，揭示了塑料中的氯限制了微生物的多样性。根瘤菌科和假单胞菌科的未分类成员是塑料包装表面的优势属，这表明它们可能是参与塑料降解过程的微生物。该研究提供了宝贵的观点，以促进对移民的全面了解，命运,以及与湿地微塑料(MPs)相关的环境风险。
