Nanoplastics potentiate mercury toxicity in a marine copepod under multigenerational exposure

• Published in: Aquatic toxicology 2023-05, Vol.258, p.106497-106497, Article 106497
• Main Authors: Xie, Dongmei, Zhang, Hongmai, Wei, Hui, Lin, Lin, Wang, Dazhi, Wang, Minghua
• Format: Article
• Language: English
• Subjects: Animals; Copepoda; Ecosystem; Life history traits; Marine copepod; Mercury - toxicity; Mercury accumulation; Microplastics; Mixture; Nanoplastics; Polystyrenes - toxicity; Transcriptome; Water Pollutants, Chemical - toxicity
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/j.aquatox.2023.106497

•Nanoplastics compromised the development and fecundity of Tigriopus japonicus.•Nanoplastics enhanced Hg bioaccumulation and its toxicity (e.g., reduced fecundity).•The defense/detoxification pathways were triggered by nanoplastics or Hg.•Combined exposure vs Hg further damaged DNA replication and reproduction pathway.•Combined nanoplastics and Hg can increase the risk of copepod's population. The continuous fragmentation of plastics and release of synthetic nanoplastics from products have been aggravating nanoplastic pollution in the marine ecosystem. The carrier role of nanoplastics may increase the bioavailability and toxicity effects of toxic metals, e.g., mercury (Hg), which is of growing concern. Here, the copepod Tigriopus japonicus was exposed to polystyrene nanoplastics (PS NPs) and Hg (alone or combined) at environmental realistic concentrations for three generations (F0-F2). Then, Hg accumulation, physiological endpoints, and transcriptome were analyzed. The results showed that the copepod's reproduction was significantly inhibited under PS NPs or Hg exposure. The presence of PS NPs caused significantly higher Hg accumulation, lower survival, and lower offspring production in copepods relative to Hg exposure, suggesting an increased threat to the copepod's survivorship and health. From the molecular perspective, combined PS NPs and Hg caused a graver effect on the DNA replication, cell cycle, and reproduction pathways relative to Hg exposure, linking to lower levels of survivorship and reproduction. Taken together, this study provides an early warning of nanoplastic pollution for the marine ecosystem not only because of their adverse effect per se but also their carrier role for increasing Hg bioaccumulation and toxicity in copepods. [Display omitted]