Research Profiles

The production of significant and increasing quantities of synthetic nanomaterials will inevitably result in the release of these materials into the natural environment. With the increased presence of nanomaterials in commercial products, a growing public debate is emerging on whether the environmental and social costs of nanotechnology outweigh its many benefits. To date, very few studies have investigated the environmental and toxicological impacts of direct and indirect exposure to nanomaterials, and there are no clear guidelines to quantify these effects.

The goal of this project is to develop a comprehensive understanding of the fate of manufactured nanomaterials in the subsurface environment (i.e., soil and groundwater). Whether nanomaterials will pose a threat of groundwater contamination will depend primarily on their stability (against degradation and agglomeration) and mobility. Mobility is controlled by how strongly the nanoparticles interact with the inorganic and organic components of the soil and aquifer materials. In addition to being possible contaminants themselves, nanoparticles may be capable of sorbing toxic materials because of their large surface area and high reactivity and hence facilitate the transport of otherwise stable contaminants in soil and groundwater aquifers.

We plan to carry out systematic studies to evaluate the mobility and transformation (e.g., agglomeration) of selected nanoparticles through integrated experiments at different scales. The following experiments are now under way: (1) dynamic light scattering experiments in a well-controlled batch system to determine agglomeration behavior of titanium dioxide (TiO₂) and iron oxide (Fe₃O₄) under conditions relevant to the subsurface environment, and (2) confocal microscopy experiments to assess attachment of these particles to various interfaces in a model soil system.

Our long-term goals for current and future studies are to provide insight into processes controlling nanoparticle stability and mobility, generate data to evaluate the utility of existing conceptual models to predict the transport of nanoparticles in porous media, and provide guidelines for evaluating exposure pathways and human health impacts that the manufactured nanomaterials may have after they are released into the environment. In addition, we hope to develop protocols that may be used to assess the fate of future nanomaterials in the subsurface environment before they enter widespread production.