Cellular Partitioning of Nanoparticulate versus Dissolved Metals in Marine Phytoplankton

• Published in: Environmental science & technology Vol. 48; no. 22; pp. 13443 - 13450
• Main Authors: Bielmyer-Fraser, Gretchen K, Jarvis, Tayler A, Lenihan, Hunter S, Miller, Robert J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 18.11.2014
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Aquatic life; Aquatic Organisms - drug effects; Biological and medical sciences; Cross-disciplinary physics: materials science; rheology; Ecotoxicology, biological effects of pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Marine and brackish environment; Materials science; Metal Nanoparticles - toxicity; Metal oxides; Metals; Metals - toxicity; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Oxides - toxicity; Physics; Phytoplankton - cytology; Phytoplankton - drug effects; Phytoplankton - growth & development; Phytoplankton - metabolism; Plankton; Population growth; Risk assessment; Thalassiosira weissflogii; Toxicity; Marine environment; Nanoparticles; Heterokontophyta; Bacillariophyta; Pollutant behavior; Algae; Metals; Phytoplankton; Phase partition; Nanostructured materials
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es501187g

Discharges of metal oxide nanoparticles into aquatic environments are increasing with their use in society, thereby increasing exposure risk for aquatic organisms. Separating the impacts of nanoparticle from dissolved metal pollution is critical for assessing the environmental risks of the rapidly growing nanomaterial industry, especially in terms of ecosystem effects. Metal oxides negatively affect several species of marine phytoplankton, which are responsible for most marine primary production. Whether such toxicity is generally due to nanoparticles or exposure to dissolved metals liberated from particles is uncertain. The type and severity of toxicity depends in part on whether phytoplankton cells take up and accumulate primarily nanoparticles or dissolved metal ions. We compared the responses of the marine diatom, Thalassiosira weissflogii, exposed to ZnO, AgO, and CuO nanoparticles with the responses of T. weissflogii cells exposed to the dissolved metals ZnCl2, AgNO3, and CuCl2 for 7 d. Cellular metal accumulation, metal distribution, and algal population growth were measured to elucidate differences in exposure to the different forms of metal. Concentration-dependent metal accumulation and reduced population growth were observed in T. weissflogii exposed to nanometal oxides, as well as dissolved metals. Significant effects on population growth were observed at the lowest concentrations tested for all metals, with similar toxicity for both dissolved and nanoparticulate metals. Cellular metal distribution, however, markedly differed between T. weissflogii exposed to nanometal oxides versus those exposed to dissolved metals. Metal concentrations were highest in the algal cell wall when cells were exposed to metal oxide nanoparticles, whereas algae exposed to dissolved metals had higher proportions of metal in the organelle and endoplasmic reticulum fractions. These results have implications for marine plankton communities as well as higher trophic levels, since metal may be transferred from phytoplankton through food webs vis à vis grazing by zooplankton or other pathways.