Toxicity of aqueous fullerene nC 60 to activated sludge: Nitrification inhibition and microtox test

Abstract

The increasing production and use of fullerene nanomaterials raised their exposure potential to the activated sludge during biological wastewater treatment process. In this study, the toxicity of aqueous nanoscaled C 60 (nC 60) to activated sludge was investigated using nitrification inhibition and Microtox test. The test solutions of nC 60 were prepared using two methods: long stirring (Stir/nC 60) and toluene exchange (Tol/nC 60). The nC 60 aggregation in test medium was also evaluated for toxicity assessment. The results showed that the nC 60 aggregation behaved differently in two test mediums during the incubation periods. The nC 60 toxicity was greatly influenced by the preparation method. Stir/nC60 presented no significant toxicity to both the nitrification sludge and bioluminescent bacteria at the maximum concentration studied. In contrast, the EC 20 of Tol/nC 60 was obtained to be 4.89mg/L (3h) for the nitrification inhibition and 3.44mg/L (30min) for Microtox test, respectively. Copyright © 2012 Yongkui Yang et al.