Acute toxicity of titanium dioxide (MTiO2 ) microparticles in Artemia salina nauplii instar I and II

Abstract

In this study, the toxicity effects of titanium dioxide (MTiO2) microparticles on A. salina nauplii instar I and II between 24 and 48 h was evaluated. The MTiO2 were characterized by X-ray Powder Diffraction (XRPD), Fourier Transform Infrared Spectra (FT-IR), Scanning Electron Microscopy (SEM), Zeta potential (ζ), Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). MTiO2 rutile phase with an average crystallite size of 114.5 ± 2.44 nm was used in toxicity tests at concentration of 12.5, 25, 50 and 100 ppm. No toxicity was observed in A. salina nauplii instar I at the time of 24 and 48 h. However, A. salina nauplii instar II toxicity was observed within 48 h of exposure. MTiO2 dispersed with concentrations of 25, 50 and 100 ppm were lethal for 30%, 50% and 30% of the individuals respectively, thus showing a significant difference (P ≤ 0.05) relative to the control group, artificial sea water (ASW). The mortality number of A. salina was recorded and LC50 value of 50 ppm was calculated. Analysis of optical and SEM revealed tissue damage and morphological changes in A. salina nauplii instar II. By using confocal laser scanning microscopy, cell damage was observed due to the toxicity of MTiO2 at a concentration of 20, 50 and 100 ppm in nauplii instar II. At this stage, A. salina was more affected by the action of MTiO2 with higher mortality rate, morphological alterations and cellular damage.