The potential intrinsic and extrinsic toxicity of silica nanoparticles and its impact on marine organisms

Abstract

The intrinsic and extrinsic toxicity of SiO2 nanoparticles (Aerosil OX50, ϕ ~ 40 nm) are investigated with a comparison to the particles in micron size (SiO2 gel, ϕ ~ 1.5 μ m). Nanoparticles potentially functioned as a carrier of harmful substances transfer was assessed by examining the surface adsorption behavior of the nanoparticles towards γ-picoline (4-methylpyridine), recognized as one type of the marine pollutants, as well as the penetration behavior of the nanoparticles towards a typical marine macro-organism (Caulerpa taxifolia). Silica nanoparticle surface can take up to 2.6 molecules/nm2 of γ-picoline in an aqueous solution comparable to the marine environment. These nanoparticles can further travel onto the surface and into the bulk of the algae (Caulerpa taxifolia) with a depth of ~ 1 μm while carrying toxic γ-picoline. The integrated intrinsic and extrinsic toxicity of SiO2 nanoparticles has a significant effect on the growth of the algae. The large surface area of the silica nanoparticles results in a high adsorption capability and allows the particles to participate in possible toxic carrier activities in water medium towards marine organisms.