Environmental fate of data poor inorganic contaminants- Developing novel tools and a better fundamental understanding

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Thousands of new products and materials, with novel properties and reactivity, are being developed each year. Indeed, many of the technology critical materials used to fabricate solar cells, high performance magnets, electronics and catalysts incorporate either the lanthanide series elements or highly reactive nanomaterials. Although these emerging products have numerous applications and a greatly expanding production, few data are available about their potential environmental impacts. One critical missing element of ecological risk assessments for these novel materials are robust determinations of their concentrations, speciation and fate in complex environmental media. The overall research objective of our group is to identify, better understand and quantify the main biophysicochemical processes that control the fate and bioavailability of metals in environmental systems. The Discovery grant will be used to develop the underpinning science and analytical capacity that is required to rigorously evaluate the ecological risk of nanomaterials and rare earth metals. Funding will support the most fundamental aspects of our research, by specifically advancing three related fields of study: (i)development of our analytical capacity to measure low concentrations of small nanoparticles in complex systems and to distinguish anthropogenic from natural NP; (ii)improvements to our fundamental understanding of the main physicochemical processes (dissolution, agglomeration, heteroagglomeration, etc.) that determine the fate of nanomaterials in natural systems; (iii)increasing our mechanistic understanding on how the chemical speciation of metals in natural systems is related to their bioavailability. For nanoparticles, their colloidal stability (with respect to agglomeration) and dissolution are certain to influence their bioavailability. Analytical developments will be pursued to provide us with a novel ability to measure the fate of the smallest nanoparticles (1-20 nm) in both real and simulated natural systems. We will perform mechanistic studies on particle fate by varying important environmental parameters. The imminent addition of a time of flight - inductively coupled mass spectrometer (ICP-TOFMS) will provide us with the capacity to distinguish engineered nanomaterials from natural colloids and allow us to more closely examine heteroagglomeration under near natural conditions. Finally, work will be designed to eludicate the mechanism underlying the apparent bioavailability of rare earth metal complexes and to determine whether or not the greater than expected biouptake leads to increased biological effects. As seen above, the proposed work is extremely interdisciplinary and fundamental in nature and is designed to increase our overall understanding of environmental risk by carefully examining the molecular basis controlling the fate and bioavailability of emerging inorganic contaminants.