Titanium dioxide (TiO2) nanoparticles are being produced and used in greater and greater quantities and the toxicological effects of these nanoparticles to environmental systems are currently not well understood. To date most of the aquatic ecotoxicological studies of the environmental effects of TiO2 nanomaterials have focused on pelagic organisms; however, many studies show that when TiO2 nanomaterials enter the environment they readily aggregate and settle from the water column. This indicates that benthic systems may be more exposed to TiO2 nanoparticles than pelagic organisms.

This Masters thesis will focus on the potential for toxic effects of TiO2 nanoparticles on benthic food chains. As benthic biofilms are composed of many different types of organisms, including primary producers (such as heterotrophic bacteria) and predacious organisms (such as nematodes, rotifers and protozoa), this Masters thesis will focus on the effects of nanoparticles to these two broad groups of test organisms. By using heterotrophic biofilms we aim to determine if nanoparticles can be taken up by heterotrophic biofilms or become trapped in the extracellular matrix of these biofilms, and do these interactions result in toxic effects to the biofilms. By using predacious organisms we aim to determine if titanium dioxide nanoparticles be transferred through a benthic food chain from benthic biofilms to biofilm predators and then determine what effects this food chain transfer has on these higher level predators.
Determining the toxicity of titanium dioxide nanoparticles to heterotrophic biofilms and the ability for trophic transfer of nanoparticles through a benthic food chain, this Masters thesis will provide much needed information for assessing the environmental implications of our growing use of TiO2 nanoparticles.