Department of Civil and Environmental Engineering, Shantou University, Shantou 515063, China; Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs of China, Tianjin 300191, China.
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs of China, Tianjin 300191, China.
J Hazard Mater. 2022 Jan 5;421:126694. doi: 10.1016/j.jhazmat.2021.126694. Epub 2021 Jul 19.
Although the compound pollution of microplastics and arsenic (As) in paddy soil can affect the growth and quality of rice, relevant research on this phenomenon was limited. Therefore, we combined a pot experiment with computational chemistry to explore the effects and mechanism of polystyrene (PSMP) and polytetrafluoroethylene (PTFE) microplastics on As bioavailability. PSMP and PTFE interacted with rice root exudates through van der Waals forces, approached the rice root system, inhibited root activity, reduced the relative abundance of Geobacteria and Anaeromyxobacter, and consequently reduced the iron plaques on the root surfaces. Consequently, As uptake by the rice was inhibited. PSMP and PTFE reduced the hemoglobin content by directly destroying its tertiary structure, thereby retarding rice growth. In contrast, As increased the hemoglobin content by inducing reactive oxygen species in rice. Under the influence of PSMP, PTFE, and As, the activities of soluble starch synthase and pyrophosphorylase in rice grains were inhibited, and starch accumulation decreased. Thus, PSMP, PTFE, and As reduced rice biomass and yield owing to their physiological toxicity and adverse impacts on root activity. Grain yields in soil with an As content of 86.3 mg·kg, 0.5% small particle-sized PSMP, and 0.5% small particle-sized PTFE decreased by 30.7%, 20.6%, and 19.4%, respectively, compared to the control. This study determined the comprehensive mechanism through which PSMP and PTFE affect As bioavailability, which is critical for managing rice biomass and low yields in As and microplastic co-contaminated soil.
尽管稻田土壤中微塑料和砷（As）的复合污染会影响水稻的生长和品质，但对此现象的相关研究有限。因此，我们结合盆栽实验和计算化学来探究聚苯乙烯（PSMP）和聚四氟乙烯（PTFE）微塑料对 As 生物有效性的影响及其机制。PSMP 和 PTFE 通过范德华力与水稻根分泌物相互作用，接近水稻根系，抑制根的活性，降低地杆菌属和厌氧单胞菌属的相对丰度，从而减少根表面的铁膜。因此，水稻对 As 的吸收受到抑制。PSMP 和 PTFE 通过直接破坏其三级结构来降低血红蛋白含量，从而抑制水稻生长。相比之下，As 通过诱导水稻中的活性氧来增加血红蛋白含量。在 PSMP、PTFE 和 As 的影响下，水稻籽粒中可溶性淀粉合酶和焦磷酸化酶的活性受到抑制，淀粉积累减少。因此，PSMP、PTFE 和 As 由于其生理毒性和对根活性的不利影响，降低了水稻的生物量和产量。与对照相比，土壤中 As 含量为 86.3 mg·kg、小粒径 PSMP 含量为 0.5%和小粒径 PTFE 含量为 0.5%时，水稻的籽粒产量分别降低了 30.7%、20.6%和 19.4%。本研究确定了 PSMP 和 PTFE 影响 As 生物有效性的综合机制，这对于管理 As 和微塑料复合污染土壤中水稻的生物量和低产至关重要。
