The uptake and effects on survival of nano silver and nano titanium dioxide in brine shrimp (Artemia nauplii)

Abstract

Particles with a size below 100 nm are called nanoparticles. Nowadays these particles can be found in a wide range of consumer products and nanotechnology is a continuously growing area of research. Even though nanoparticles have a lot of convenient characteristics some have already proven to be quite toxic, especially to aquatic life forms. In this report an exposure study of brine shrimp (Artemia nauplii) is described. Brine shrimp were exposed to 4 different concentrations of silver and titanium dioxide, both nano and bulk. The particles were characterised by use of a zetasizer and their actual size was determined. To compare the effects of silver ions and nano silver an additional group of brine shrimp was exposed to silver nitrate. The control group was exposed to bovine serum albumin, since this was added to all solutions to keep the nanoparticles in suspension. After 6, 12 and 24 hours lethality was assessed. For each substance the mean survival after 24 hours was calculated per concentration. These results were compared to the survival in the control group. In the silver and titanium groups the lowest concentrations showed the largest effect on survival, whereas in the silver nitrate the highest concentration was most lethal. The characterisation of the particles showed a wide spread in sizes and most particles were much larger than the advertised size. This was due to high aggregation of the particles. Because of this and the similar results for the nano and bulk in the lethality test no conclusions can be made about size dependent effects. However it can be concluded that agglomerates do cause a decrease in survival.