National Engineering Research Center of Protected Agriculture, Shanghai Engineering Research Center of Protected Agriculture, Tongji University, Shanghai 200092, China; State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Water Res. 2024 Aug 1;259:121841. doi: 10.1016/j.watres.2024.121841. Epub 2024 May 26.
The toxicity of microplastics (MPs) on freshwater plants has been widely studied, yet the influence of aged MPs remains largely unexplored. Herein, we investigated the influence of polyvinyl chloride (PVC) MPs, both before and after aging, at different environmentally relevant concentrations on Chlorella pyrenoidosa, a freshwater microalgae species widely recognized as a valuable biomass resource. During a 96-h period, both virgin and aged MPs hindered the growth of C. pyrenoidosa. The maximum growth inhibition rates were 32.40 % for virgin PVC at 250 mg/L and 44.72 % for aged PVC at 100 mg/L, respectively. Microalgae intracellular materials, i.e., protein and carbohydrate contents, consistently decreased after MP exposure, with more pronounced inhibition observed with aged PVC. Meanwhile, the MP aging significantly promoted the nitrogen uptake of C. pyrenoidosa, i.e., 1693.45 ± 42.29 mg/L (p < 0.01), contributing to the production of humic acid-like substances. Additionally, aged PVC induced lower chlorophyll a and Fv/Fm when compared to virgin PVC, suggesting a more serious inhibition of the photosynthesis process of microalgae. The toxicity of MPs to C. pyrenoidosa was strongly associated with intercellular oxidative stress levels. The results indicate that MP aging exacerbates the damage to photosynthetic performance and bioenergy production in microalgae, providing critical insights into the toxicity analysis of micro(nano)plastics on freshwater plants.
微塑料（MPs）对淡水植物的毒性已得到广泛研究，但老化 MPs 的影响在很大程度上仍未得到探索。在此，我们研究了聚氯乙烯（PVC） MPs 在不同环境相关浓度下的原始和老化状态对淡水微藻物种栅藻的影响，栅藻被广泛认为是有价值的生物质资源。在 96 小时的时间内，原始和老化 MPs 均阻碍了栅藻的生长。在 250mg/L 时，原始 PVC 的最大生长抑制率为 32.40%，在 100mg/L 时，老化 PVC 的最大生长抑制率为 44.72%。暴露于 MPs 后，微藻细胞内物质（即蛋白质和碳水化合物含量）持续下降，老化 PVC 的抑制作用更为明显。同时，MP 老化显著促进了栅藻的氮吸收，即 1693.45±42.29mg/L（p<0.01），有助于产生腐殖酸样物质。此外，与原始 PVC 相比，老化 PVC 诱导的叶绿素 a 和 Fv/Fm 更低，表明微藻光合作用过程受到更严重的抑制。 MPs 对栅藻的毒性与细胞间氧化应激水平密切相关。结果表明，MP 老化加剧了对微藻光合作用性能和生物能生产的破坏，为分析微（纳）塑料对淡水植物的毒性提供了重要的见解。
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