Center of Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China; University of Chinese Academy of Sciences, Beijing, China.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
Aquat Toxicol. 2024 Aug;273:107024. doi: 10.1016/j.aquatox.2024.107024. Epub 2024 Jul 14.
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.
随着环境意识的提高，可回收塑料的使用有所增加。然而，目前尚不清楚再生微塑料 (MPs) 是否比原始 MPs 带来更小或更大的环境风险。镉 (Cd) 是一种对大多数生物都具有毒性的物质，可以与 MPs 结合并在沉积物中积累。很少有研究探讨过与 Cd 共存的再生 MPs 和原始 MPs 对有根大型植物带来的环境风险。我们研究了再生聚氯乙烯 MPs (R-PVC-MPs) 和原始聚氯乙烯 MPs (PVC-MPs) 在存在和不存在 Cd 的情况下对苦草的影响。结果表明，在中等和高 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 的鲜重明显低于暴露于 PVC-MPs 的。此外，R-PVC-MPs 对 V. natans 的生理特性的负面影响大于 PVC-MPs，因为所有 Cd 水平下的叶绿素均显著降低。在高 Cd 水平下，R-PVC-MPs 和 PVC-MPs 均导致明显的高氧化应激，没有观察到显著差异。PCoA 图表明，不同的 MPs 在相同的 Cd 浓度下会引起明显的变化。性状网络图表明性状之间存在强烈的相互作用，其中 R-PVC-MPs 表现出最高的复杂性。较低的平均度和减少的边缘密度表明添加 R-PVC-MPs 的植物的性状彼此之间更加独立。我们的研究结果表明，再生聚氯乙烯 MPs 比原始聚氯乙烯 MPs 带来更大的环境风险，为评估再生塑料在淡水生态系统中的风险提供了参考。
