(217c) Synthesis of Labeled TiO2 Nanoparticles as a Tool for Examining the Environmental Transport and Fate of Engineered Nanoparticles

As public concern for the environmental consequences of the inclusion of manufactured nanomaterials in products is growing, research on these aspects is only starting to gain momentum. It is now accepted that manufactured nanoparticles are entering the environment and may have harmful effects on certain organisms. However, little is known about how manufactured nanoparticles interact with environmental matrices like soils, sediments and natural waters. These interactions will govern environmental fate, transport and transformation and will ultimately control exposure (concentration and form of nanomaterials) to organisms in natural environments. A primary factor limiting access to this information is the lack of suitable methods for detecting manufactured nanoparticles in environmental matrices. For some classes of nanomaterials, a major issue is simply distinguishing between manufactured nanoparticles and the natural background concentration of the element(s) in question.

We are working to develop a methodology to prepare TiO₂ nanoparticles labeled with elements that have low background concentrations in the environment (e.g., lanthanides, gold, etc); the concentration of the tracer element can therefore be used as a proxy identifier for the presence of the nanoparticles. Preliminary investigations have focused on hafnium and europium as tracer elements, but other dopants are currently being evaluated. We will discuss nanoparticle synthesis procedures, characterization of the physical/chemical characteristics of the labeled particles in comparison to their unlabeled counterparts, and evaluation of the utility of labeled nanoparticles through quantification of removal during conventional water treatment processes.