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

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 -Al2O3 (50 nm and 3.5 m) and -Al2O3 (5 nm and 0.4 m) 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 mu m for spherical NPs and from 250 to 756 nm for rod-shaped NPs. The phase contrast microscope images showed that NPs deposited inside the guts as aggregates. Inductively coupled plasma mass spectrometry analysis showed that large particles (3.5 m -Al2O3) were not taken up by Artemia, whereas fine NPs (0.4 m -Al2O3) and ultra-fine NPs (5 nm -Al2O3 and 50 nm -Al2O3) accumulated substantially. Differences in toxicity were detected as changing with NP size and morphology. The malondialdehyde levels indicated that smaller -Al2O3 (5 nm) NPs were more toxic than larger -Al2O3 (0.4 mu m) particulates in 96 h. The highest mortality was measured as 34% in 96 h for -Al2O3 NPs (5 nm) at 100 mg/L (LC50 > 100 mg/L). -Al2O3 NPs were more toxic than -Al2O3 NPs at all conditions. (c) 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 109-118, 2015.