As environmental awareness increases, the use of recyclable plastics has risen. However, it is currently unclear whether recycled microplastics (MPs) pose a lesser or greater environmental risk than pristine MPs. Cadmium (Cd), known for its toxicity to most organisms, can bind with MPs and accumulate in sediments. Few studies have explored the environmental risks posed by the coexistence of recycled MPs and pristine MPs with Cd to rooted macrophytes. We investigated the effects of recycled PVC MPs (R-PVC-MPs) and pristine PVC MPs (PVC-MPs) on Vallisneria natans in the presence and absence of Cd. Results showed that at moderate and high Cd levels, R-PVC-MPs reduced plant Cd enrichment. Despite this, the fresh weight of V. natans exposed to R-PVC-MPs was significantly lower than those exposed to PVC-MPs. Furthermore, R-PVC-MPs had more negative impacts on the physiological traits of V. natans than PVC-MPs, as chlorophyll was significantly reduced across all Cd levels. At high Cd levels, both R-PVC-MPs and PVC-MPs caused significantly high oxidative stress, with no significant differences observed. The PCoA plot showed that different MPs cause noticeable variations within the same Cd concentration. The trait network diagrams illustrated strong interactions among traits, with R-PVC-MPs showing the highest complexity. Lower average degree and decreased edge density indicate that traits of plants with R-PVC-MPs addition are more independent of each other. Our findings suggest that recycled PVC MPs pose a greater environmental risk than pristine PVC MPs, offering reference for assessing the risks of recycled plastics in freshwater ecosystems.

中文翻译：

---

可回收塑料环保吗？回收的 PVC 微塑料在 Vallisneria natan 上显示出比原始 PVC 更高的毒性，无论镉含量如何


随着环保意识的提高，可回收塑料的使用有所增加。然而，目前尚不清楚回收的微塑料 （MP） 是否比原始微塑料 MP 构成更小或更大的环境风险。镉 （Cd） 以其对大多数生物体的毒性而闻名，可以与 MP 结合并积聚在沉积物中。很少有研究探讨回收的 MP 和原始 MP 与 Cd 共存对根系大型植物所带来的环境风险。我们研究了在存在和不存在 Cd 的情况下，回收的 PVC MPs （R-PVC-MPs） 和原始 PVC MPs （PVC-MPs） 对 Vallisneria natans 的影响。结果表明，在中高 Cd 水平下，R-PVC-MPs 降低了植物 Cd 富集。尽管如此，暴露于 R-PVC-MPs 的 V. natans 的鲜重显著低于暴露于 PVC-MPs 的 V. natans。此外，R-PVC-MPs 对 V. natans 生理特性的负面影响大于 PVC-MPs，因为所有 Cd 水平的叶绿素均显著减少。在高 Cd 水平下，R-PVC-MPs 和 PVC-MPs 均引起显著的高氧化应激，未观察到显著差异。PCoA 图显示，不同的 MP 在相同的 Cd 浓度内会引起显著变化。性状网络图说明了性状之间的强相互作用，其中 R-PVC-MP 显示出最高的复杂性。较低的平均度和较低的边缘密度表明添加 R-PVC-MPs 的植物的性状彼此更加独立。我们的研究结果表明，再生 PVC MPS 比原始 PVC MP 构成更大的环境风险，为评估再生塑料在淡水生态系统中的风险提供了参考。