Unraveling individual and combined toxicity of nano/microplastics and ciprofloxacin to Synechocystis sp. at the cellular and molecular levels

• Published in: Environment international Vol. 157; p. 106842
• Main Authors: You, Xiuqi, Cao, Xiaoqiang, Zhang, Xuan, Guo, Jianhua, Sun, Weiling
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2021; Elsevier
• Subjects: adhesion; adsorption; Antibiotics; cell growth; ciprofloxacin; ecotoxicology; environment; glycerophospholipids; metabolism; Metabolomics; Microplastics; Nanoplastics; nucleotides; primary productivity; reactive oxygen species; Synechocystis; Toxicity; tricarboxylic acid cycle; Metabolomics; Microplastics; Antibiotics; Toxicity; Nanoplastics
• DOI: 10.1016/j.envint.2021.106842
• ISSN: 0160-4120; 1873-6750

[Display omitted] •Co-pollution of CIP and nano/microplastics showed antagonistic toxicity.•CIP adsorption on nano/microplastics resulted in their antagonistic effects.•Metabolomics revealed the toxicity mechanisms of CIP and nano/microplastics.•Multiple growth-cycle exposure highlighted risks of nano/microplastics in natural water. Although nanoplastics/microplastics (NPs/MPs) may interact with co-contaminants (e.g. antibiotics) in aquatic systems, little is known about their combined toxicity. Here, we compared the individual toxicity of NPs/MPs or ciprofloxacin (CIP, a very commonly detected antibiotic) and their combined toxicity toward a unicellular cyanobacterium Synechocystis sp. in terms of the cellular responses and metabolomic analysis. We found that CIP exhibited an antagonistic effect with NPs/MPs due to its adsorption onto the surface of NPs/MPs. Particle size-dependent toxic effects of NPs/MPs were observed. Reactive oxygen species (ROS) was verified as an important factor for NPs/MPs to inhibit cell growth, other than for CIP. Metabolomics further revealed that Synechocystis sp. up-regulated glycerophospholipids, amino acids, nucleotides, and carbohydrates to tolerate CIP pressure. NPs/MPs downregulated the TCA cycle and glycerophospholipids metabolism and impaired the primary production and membrane integrity via adhesion with Synechocystis sp.. Additionally, the toxicity of NPs/MPs throughout ten growth cycles at a sublethal concentration unveiled its potential risks in interfering with metabolism. Collectively, our findings provide insights into the joint ecotoxicity of NPs/MPs and antibiotics, and highlight the potential risks of co-pollutants at environmental relevant concentrations.