The vast majority of studies measure the toxic effect of organisms exposed to nanoparticles (NPs) while there is still a lack of knowledge about the influence of NPs on the aquatic environment. It is unknown whether or not the interaction between NPs and algae will result in the variation of algal organic matter (AOM) and stimulate the production of more algal toxins. In this study, zinc oxide nanoparticles (nano-ZnO) as a typical representative of metal oxide NPs were used to evaluate the toxic effects and environmental feedback of Microcystis aeruginosa. Reactive oxygen species (ROS) and malondialdehyde (MDA) were measured to explain the toxicity mechanism. Changes of AOM, including the production of toxins, the molecular weight distribution and the excitation-emission matrices of algal solution were also studied as environmental feedback indicators after nano-ZnO destroyed the algae. As the nano-ZnO exceeded the comparable critical concentration (1.0 mg/L), the algae were destroyed and intracellular organic matters were released into the aquatic environment, which stimulated the generation of microcystin-LR (MC-LR). However, it is worth noting that the concentration of nano-ZnO would need to be high (at mg/L range) to stimulate more MC-LR production. These findings are expected to be beneficial in interpreting the toxicity and risks of the releasing of NPs through the feedback between algae and the aquatic environment.

绝大多数研究测量了暴露于纳米颗粒（NPs）的生物的毒性作用，但仍然缺乏关于NPs对水生环境影响的知识。尚不清楚NP与藻类之间的相互作用是否会导致藻类有机质（AOM）的变化并刺激更多藻毒素的产生。在这项研究中，使用氧化锌纳米颗粒（nano-ZnO）作为金属氧化物NPs的典型代表来评估铜绿微囊藻的毒性作用和环境反馈。测量了活性氧（ROS）和丙二醛（MDA）来解释其毒性机理。还研究了纳米ZnO破坏藻类后AOM的变化，包括毒素的产生，藻类溶液的分子量分布和激发-发射矩阵，作为环境反馈指标。当纳米ZnO超过临界浓度（1.0 mg / L）时，藻类被破坏，细胞内有机物释放到水生环境中，从而刺激了微囊藻毒素-LR（MC-LR）的产生。但是，值得注意的是，纳米ZnO的浓度需要较高（在mg / L范围内）以刺激更多的MC-LR产生。