Buckminsterfullerene's (C60) octanol-water partition coefficient (Kow) and aqueous solubility

To assess the risk and fate of fullerene C(60) in the environment, its water solubility and partition coefficients in various systems are useful. In this study, the log K(ow) of C(60) was measured to be 6.67, and the toluene-water partition coefficient was measured at log K(tw) = 8.44. From these values and the respective solubilities of C(60) in water-saturated octanol and water-saturated toluene, C(60)'s aqueous solubility was calculated at 7.96 ng/L(1.11 x 10(-11) M)for the organic solvent-saturated aqueous phase. Additionally, the solubility of C(60) was measured in mixtures of ethanol-water and tetrahydrofuran-water and modeled with Wohl's equation to confirm the accuracy of the calculated solubility value. Results of a generator column experiment strongly support the hypothesis that clusters form at aqueous concentrations below or near this calculated solubility. The K(ow) value is compared to those of other hydrophobic organic compounds, and bioconcentration factors for C(60) were estimated on the basis of K(ow).