Evaluation of Alpha and Gamma Aluminum Oxide Nanoparticle Accumulation Toxicity and Depuration in Artemia Salina Larvae

摘要

In this study, Artemia salina (crustacean filter feeders) larvae were used as a test model to investigate the toxicity of aluminum oxide nanoparticles (Al2O3 NPs) on marine microorganisms. The uptake, toxicity and elimination of α-Al2O3 (50 nm and 3.5 μm) and γ-Al2O3 (5 nm and 0.4 μm) NPs were studied. Twenty-four and ninety-six hour exposures of different concentrations of Al2O3 NPs to Artemia larvae were conducted in a seawater medium. When suspended in water, Al2O3 NPs aggregated substantially with the sizes ranging from 6.3 nm to > 0.3 μm for spherical NPs, and from 250 to 756 nm for rod-shaped NPs. The phase contrast microscope images revealed that NPs deposited inside the guts as aggregates. ICP-MS analysis showed that large particles (3.5 μm α-Al2O3) were not taken up by Artemia, while fine NPs (0.4 μm γ-Al2O3) and ultra-fine NPs (5 nm γ-Al2O3 and 50 nm α-Al₂O₃) accumulated substantially. Differences in toxicity were detected as changing with NP size and morphology. The malondialdehyde (MDA) levels indicated that smaller γ-Al₂O₃ (5 nm) NPs were more toxic than larger γ-Al₂O₃ (0.4 μm) particulates in 96 h. The highest mortality was measured as 34% in 96 h for γ-Al₂O₃ NPs (5 nm) at 100 mg/L (LC₅₀ > 100 mg/L). γ-Al₂O₃ NPs were more toxic than α-Al₂O₃ NPs at in all conditions.