Su Yuanyuan, Gao Liu, Xu Elvis Genbo, Peng Licheng, Diao Xiaoping, Zhang Yumeng, Bao Ruiqi
Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou 570228, China; School of Environmental Science and Engineering, Hainan University, Haikou 570228, China; State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou 570228, China; School of Environmental Science and Engineering, Hainan University, Haikou 570228, China.
Water Res. 2025 Apr 1;273:123008. doi: 10.1016/j.watres.2024.123008. Epub 2024 Dec 18.
Microplastics (MPs) commonly coexist with microalgae in aquatic environments, can heteroaggregate during their interaction, and potentially affect the migration and impacts of MPs in aquatic environments. The hetero-aggregation may also influence the fate of other pollutants through MPs' adsorption or alter their aquatic toxicity. Here, we explored the hetero-aggregation process and its key driving mechanism that occurred between green microalga Chlorella vulgaris (with a cell size of 2-10 μm) and two types of MPs (polystyrene and polylactide, 613 μm). Furthermore, we investigated the environmental impacts of the microplastics-microalgae aggregates (MPs-microalgae aggregates) by comparing their adsorption of Cu(II) with that of pristine MPs and evaluating the effects of hetero-aggregation on MPs aging and their toxicity to microalgae. Our results indicated that microalgal colonization occurred on the surface of MPs, possibly through electrostatic interactions, hole-filling, hydrophilic interactions, and algae-bacteria symbiosis. The hetero-aggregation led to a stronger Cu(II) adsorption by MPs-microalgae aggregates than pristine MPs due to electrostatic interactions, coordination, complexation, and ion exchange. Exposure to either MPs (pristine or aged) or Cu(II) inhibited the cell growth of C. vulgaris, while the integrated biomarker response (IBR) showed more pronounced inhibitory effects resulting from aged MPs compared to pristine MPs and an antagonistic effect on microalgae was caused by the co-exposure to MPs and Cu(II). These findings suggest that the hetero-aggregation of MPs and microalgae may alter their environmental fates and co-pollutant toxicity.
微塑料（MPs）在水生环境中通常与微藻共存，在相互作用过程中会发生异质聚集，并可能影响微塑料在水生环境中的迁移和影响。这种异质聚集还可能通过微塑料的吸附作用影响其他污染物的归宿，或改变其水生毒性。在此，我们探究了普通小球藻（细胞大小为2-10μm）与两种微塑料（聚苯乙烯和聚乳酸，613μm）之间发生的异质聚集过程及其关键驱动机制。此外，我们通过比较微塑料-微藻聚集体（MPs-微藻聚集体）与原始微塑料对Cu(II)的吸附情况，并评估异质聚集对微塑料老化及其对微藻毒性的影响，来研究微塑料-微藻聚集体的环境影响。我们的结果表明，微藻可能通过静电相互作用、填孔、亲水相互作用和藻菌共生等方式在微塑料表面定殖。由于静电相互作用、配位、络合和离子交换，异质聚集导致MPs-微藻聚集体对Cu(II)的吸附比原始微塑料更强。暴露于微塑料（原始或老化的）或Cu(II)都会抑制普通小球藻的细胞生长，而综合生物标志物响应（IBR）显示，与原始微塑料相比，老化微塑料对微藻的抑制作用更明显，并且微塑料和Cu(II)共同暴露对微藻产生了拮抗作用。这些发现表明，微塑料和微藻的异质聚集可能会改变它们在环境中的归宿以及共污染物的毒性。
