Toxicity and Transcriptomic Analysis in Hyalella azteca Suggests Increased Exposure and Susceptibility of Epibenthic Organisms to Zinc Oxide Nanoparticles

• Published in: Environmental science & technology 2013-08, Vol.47 (16), p.9453-9460
• Main Authors: Poynton, Helen C, Lazorchak, James M, Impellitteri, Christopher A, Blalock, Bonnie, Smith, Mark E, Struewing, Katherine, Unrine, Jason, Roose, Deborah
• Format: Article
• Language: English
• Subjects: Amphipoda - drug effects; Amphipoda - metabolism; Animal, plant and microbial ecology; Animals; Applied ecology; Aquatic ecology; Biological and medical sciences; Cross-disciplinary physics: materials science; rheology; Crustaceans; Dissolution; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Profiling; Hyalella azteca; Materials science; Nanomaterials; Nanoparticles; Nanoparticles - toxicity; Nanoscale materials and structures: fabrication and characterization; Physics; Risk Assessment; Sediments; Toxicity; Toxicity Tests, Acute; Zinc Oxide - toxicity; Zinc oxides; Zinc Sulfate - toxicity
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es401396t

Nanoparticles (NPs) are expected to make their way into the aquatic environment where sedimentation of particles will likely occur, putting benthic organisms at particular risk. Therefore, organisms such as Hyalella azteca, an epibenthic crustacean which forages at the sediment surface, is likely to have a high potential exposure. Here we show that zinc oxide (ZnO) NPs are more toxic to H. azteca compared with the corresponding metal ion, Zn2+. Dissolution of ZnO NPs contributes about 50% of the Zn measured in the ZnO NP suspensions, and cannot account for the toxicity of these particles to H. azteca. However, gene expression analysis is unable to distinguish between the ZnO NP exposures and zinc sulfate (ZnSO4) exposures at equitoxic concentrations. These results lead us to hypothesize that ZnO NPs provide an enhanced exposure route for Zn2+ uptake into H. azteca, and possibly other sediment dwelling organisms. Our study supports the prediction that sediment dwelling organisms are highly susceptible to the effects of ZnO NPs and should be considered in the risk assessment of these nanomaterials.