| Summary: | Industrial scale production, coupled with unique material properties, underpin
rising concerns of nano-scale materials inadvertently impacting the health and function of
natural systems. Fullerenes, C60 in particular, have been proposed for a variety of
applications and are soon expected to be produced in multi-ton quantities. Understanding
how these materials behave in natural matrixes, specifically aqueous systems, is needed
for accurate risk assessment and to manage waste disposal practices appropriately.
Research presented here addresses outstanding questions and expands upon
current knowledge regarding C60 nano-scale aggregation in water (nano-C60). Four areas
of focus are: 1.) Aggregate formation, composition, and stability 2.) Reactivity with a
dissolved reactant (ozone) 3.) Association with mineral surfaces and 4.) Interaction with
selected biological systems. Results indicate that aggregates are crystalline in order and
remain as underivatized C60 throughout the formation/stabilization process. The
aggregate suspensions readily react with dissolved ozone resulting in a molecularly
soluble, highly oxidized fullerene. Furthermore, nano-C60 associates with mineral
surfaces as a function of surface charge and is observed to accumulate at the cell wall of a
fungal culture. Taken together, results indicate that nano-scale, fullerene aggregates must
be considered appropriately, as they deviate from predictions based on bulk and
molecular property estimates.
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