Nanotox: Cross-Media Environmental Transport, Transformation, and Fate of Manufactured Carbonaceous Nanomaterials

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0537117 Marr Research that accounts for cross-media effects is needed to understand the environmental fate of manufactured nanomaterials. All known studies of manufactured nanomaterials in aquatic systems have used the pure, or "fresh," form of the compounds. However, nanoparticles that are released into the atmosphere undergo transformations (coagulation, coating, and reactions) that will change the particles' size, chemical composition, and surface properties. When these "aged" particles later deposit onto the earth's surface, they may have very different fates in the aquatic and terrestrial environments compared to the "fresh" compounds.Objectives: The overall objective of this research is to conduct a cross-media assessment of the transport, transformation, and fate of manufactured nanomaterials in atmospheric, aquatic, and terrestrial environments. A key component of the project is to examine how "fresh" versus atmospherically "aged" nanomaterials behave in aquatic and terrestrial systems. The experiments focus on carbonaceous nanomaterials (CNMs, including fullerenes, endohedral metallofullerenes, and carbon nanotubes) that are being produced in large quantities at a facility in Virginia.Experimental approach: In the first set of experiments, we will determine the mechanisms and rates at which airborne CNMs transform under naturally occurring conditions. In the second set of experiments, we will examine the interactions of both "fresh" and atmospherically "aged" CNMs with water and soil in order to evaluate their environmental transport and reactivity. Specific tasks are to (1) calibrate a photoemission detector for the fast, real-time detection of airborne CNMs; (2) quantify the rate of reaction of airborne CNMs with ozone; (3) age CNMs in an outdoor aerosol processing chamber; (4) evaluate transport of "fresh" and atmospherically "aged" CNMs in porous media; (5) develop CNM-functionalized atomic force microscope tips; and (6) characterize CNM interactions with soil surfaces in aquatic systems.