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C60 reduces the bioavailability of mercury in aqueous solutions

Abstract

The effects of C60 on mercury bioavailability and sorption were investigated at different C60 dosages, reaction times, and pH ranges[…]. The results demonstrated that the bioavailability of mercury (Hg(2+)) decreased with increasing C60 dosage. Approximately 30% of aqueous mercury became biologically unavailable 2h after interaction with C60 at a mass ratio of C60 to mercury as low as 0.01. However, this reduction in bioavailability plateaued at a mass ratio of C60 to mercury of 10 with a further increase in C60 concentrations resulting in only a 20% additional decrease in bioavailability. If this reduction in bioluminescence output is attributable to mercury sorption on C60, then each one log-order increase in C60 concentration resulted in a 0.86 log-order decrease in the mercury partitioning coefficient (Kd). This relationship implies the presence of high mercury-affinitive sites on C60. [..] These results suggest that C60 may be useful in capturing soluble mercury and thus reducing mercury biotoxicity.

Highlights

  • 30% of Hg2+ became biologically unavailable when C60 is 1% of the mass of Hg2+
  • Increase in C60 dosage reduces mercury bioavailability.
  • Reaction time length is more important than C60 dosage.
  • Lowering solution pH from 7.2 to 5.8 decreases mercury bioavailability.
  • The pH effect is more significant at lower C60 dosages

Conclusions

Based on the bioavailability profiles of the E. coli ARL1 bioluminescent bioreporter, it was demonstrated that C60 is efficient in reducing the bioavailability of Hg2+ through association primarily mediated by sorption. The sorption efficiency varies with C60 dosage, reaction time, and pH. Specific findings of this study are:
  • Increases in C60 dosage reduce mercury bioavailability. Thirty percent of Hg2+ became unavailable to the ARL1 bioreporter bacteria when the mass ratio of C60 to Hg2+ was 0.01.
  • The length of reaction time plays a more important role than C60 dosage in reducing Hg2+ bioavailability, suggesting slow kinetics of the C60–Hg interactions.
  • Lowering the solution pH from 7.2 to 5.8 decreases mercury bioavailability, and this effect is more significant at lower C60
  • dosages.

(PDF) C60 reduces the bioavailability of mercury in aqueous solutions. Available from: https://www.researchgate.net/publication/257813518_C60_reduces_the_bioavailability_of_mercury_in_aqueous_solutions [accessed Jun 17 2018].

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