Abstract：
With advances in plastic resource utilization technologies, polystyrene (PS) and sulfonated polystyrene (SPS) microplastics continue to be produced and retained in environmental media, potentially posing greater environmental risks. These plastics, due to their different physicochemical properties, may have different environmental impacts when compounded with other pollutants. The objective of this study was to investigate the combined toxic effects of PS and SPS on wheat using cadmium (Cd) as a background contaminant. The results demonstrated that Cd significantly impeded the normal growth of wheat by disrupting root development. Both PS and SPS exhibited hormesis at low concentrations and promoted wheat growth. Under combined toxicity, PS reduced oxidative stress and promoted the uptake of essential metal elements in wheat. Additionally, KEGG pathway analysis revealed that PS facilitated the repair of Cd-induced blockage of the TCA cycle and glutathione metabolism. However, high concentrations of SPS in combined toxicity not only enhanced oxidative stress and interfered with the uptake of essential metal elements, but also exacerbated the blocked TCA cycle and interfered with pyrimidine metabolism. These differences are related to the different stability (Zeta potential, Hydrodynamic particle size) of the two microplastics in the aquatic environment and their ability to carry heavy metal ions, especially Cd. The results of this study provide important insights into understanding the effects of microplastics on crops in the context of Cd contamination and their environmental and food safety implications.
摘要：
随着塑料资源利用技术的进步，聚苯乙烯（PS）和磺化聚苯乙烯（SPS）微塑料继续生产并保留在环境介质中，可能带来更大的环境风险。这些塑料,由于它们不同的物理化学性质，当与其他污染物混合时，可能会产生不同的环境影响。本研究的目的是以镉（Cd）为背景污染物，研究PS和SPS对小麦的联合毒性作用。结果表明，Cd通过破坏根系发育，显著阻碍了小麦的正常生长。PS和SPS在低浓度下都表现出兴奋作用，并促进了小麦的生长。在联合毒性下，PS降低了小麦的氧化应激，促进了小麦对必需金属元素的吸收。此外,KEGG通路分析显示，PS促进了Cd诱导的TCA循环阻断和谷胱甘肽代谢的修复。然而,高浓度SPS的复合毒性不仅增强了氧化应激，而且干扰了必需金属元素的摄取，但也加剧了TCA循环的阻滞并干扰了嘧啶的代谢。这些差异与不同的稳定性(Zeta电位，水动力粒径）两种微塑料在水生环境中的携带重金属离子的能力，尤其是Cd。这项研究的结果提供了重要的见解，以了解在Cd污染及其对环境和食品安全的影响的背景下，微塑料对作物的影响。
