Institute of Marine Science and Technology, Shandong University, Qingdao 266237, PR China.
Institute of Marine Science and Technology, Shandong University, Qingdao 266237, PR China.
Sci Total Environ. 2022 Jul 10;829:154571. doi: 10.1016/j.scitotenv.2022.154571. Epub 2022 Mar 15.
The combined toxic effects of nanoplastics and heavy metals on aquatic organisms have attracted widespread attention; however, the results are inconsistent and the mechanisms remain unclear. In this study, the single and combined toxicity effects of Cu and two types of polystyrene nanoplastics (PS-NPs; 50 nm PS and 55 nm PS-COOH) on Platymonas helgolandica var. tsingtaoensis were investigated, including growth inhibition, chlorophyll content, and oxidative stress. An adverse dose-response relationship on growth inhibition was found in the Cu treatment groups, which was related to the decrease in chlorophyll content and damage to cell membranes. The growth inhibitory effect of PS-NPs on microalgae increased with exposure time and concentration, and no significant difference was found in the two types of PS-NPs because of the negligible contribution of functional groups. A more significant increase in chlorophyll content was found in PS treatments than in PS-COOH treatments at 96 h because of the microscale aggregates formed by PS. Higher concentrations (≥ 50 mg/L) of PS-NPs caused membrane lipid peroxidation, which might be responsible for growth inhibition. In the combined exposure experiments, a synergistic effect on the growth inhibition rate was obtained using the independent action model and Abbott model. Combined exposure triggered more severe oxidative damage to the microalgae. Adsorption experiment results showed that there was no adsorption between PS-NPs and Cu, while the interaction of Cu and algal cells could be promoted due to the presence of the PS-NPs, which explained the increasing combined toxicity. This study could improve our understanding of the combined toxicity of nanoplastics and heavy metals and could provide a new explanation for the mechanism of combined toxicity.
纳米塑料和重金属对水生生物的联合毒性作用引起了广泛关注；然而，结果不一致，其机制仍不清楚。在这项研究中，研究了 Cu 和两种类型的聚苯乙烯纳米塑料（PS-NPs；50nm PS 和 55nm PS-COOH）对青岛大扁藻的单一和联合毒性作用，包括生长抑制、叶绿素含量和氧化应激。Cu 处理组的生长抑制表现出不利的剂量-反应关系，这与叶绿素含量的降低和细胞膜损伤有关。PS-NPs 对微藻的生长抑制作用随暴露时间和浓度的增加而增加，由于功能基团的贡献可以忽略不计，两种类型的 PS-NPs 之间没有发现显著差异。由于 PS 形成的微尺度团聚体，PS 处理在 96h 时发现叶绿素含量的增加更为显著，而 PS-COOH 处理则不然。较高浓度（≥50mg/L）的 PS-NPs 会引起膜脂质过氧化，这可能是生长抑制的原因。在联合暴露实验中，使用独立作用模型和 Abbott 模型得到了对生长抑制率的协同作用。联合暴露对微藻造成了更严重的氧化损伤。吸附实验结果表明，PS-NPs 和 Cu 之间没有吸附，而由于 PS-NPs 的存在，Cu 和藻类细胞之间的相互作用可以得到促进，这解释了联合毒性的增加。这项研究可以提高我们对纳米塑料和重金属联合毒性的认识，并为联合毒性的机制提供新的解释。
