Fate of radiolabeled C60 fullerenes in aged soils

Abstract

Fullerenes (e.g. C60, C70, etc.) present in soil may undergo changes in its retention with aging. In this study, the partitioning behavior of (14C)-C60 aged up to 12 weeks was investigated in biosolids-amended soil. Spiked samples were subjected to sequential partitioning using water, methanol, and toluene followed by total combustion of solids; the distribution of 14C across solvents and matrices were used to provide insights on C60 behavior. In most samples, 14C only partitioned in toluene with the remaining (non-extractable) activity detected in the solid phase. In all biosolids-amended soil samples, an increase in non-extractable 14C were observed for those exposed to light (vs dark) with the greatest difference observed in biosolids + sand samples. Possible processes that contribute to the observed 14C distribution, i.e. retention and potential transformation of C60, were discussed. Over-all, results suggest that environmental exposure to C60 and potentially transformed C60 species, as a result of their release from soils, is likely to be low.