Environmental Transport, Biodegradation, and Bioaccumulation of Quantum Dots and Oxide NanoparticlesEPA Grant Number: R833861
Title: Environmental Transport, Biodegradation, and Bioaccumulation of Quantum Dots and Oxide Nanoparticles
Investigators: Aga, Diana S. , Banerjee, Sarbajit , Colon, Luis , Watson, David
Institution: University of Buffalo
EPA Project Officer: Lasat, Mitch
Project Period: July 1, 2008 through June 30, 2011
Project Amount: $400,000
RFA: Exploratory Research: Nanotechnology Research Grants Investigating Fate, Transport, Transformation, and Exposure of Engineered Nanomaterials: A Joint Research Solicitation - EPA, NSF, & DOE (2007) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
This research aims to investigate the influence of size and surface chemistry of quantum dots (QD) (i.e. CdS and CdSe) and engineered metal oxide (MO) nanomaterials (i.e. CeO2, HfO2, ZrO2, TiO2) on their environmental mobility, biodegradation, and bioaccumulation. The specific goals are to:  characterize the influence of natural organic matter (NOM) on the surface functionalization, solubility, and stability of QD and MO suspensions,  examine the effects of NOM on the transport behavior and degradation of various formulations of QD and MO in soil columns,  determine the biodegradability of QD and MO in activated sludge systems as a function of surface functionalization; and  measure the bioaccumulation of QD and MO as a function of size and NOM concentration in a model organism (Eisenia fetida). We hypothesize that size, surface chemistry, bioavailability, and solubility of QD and MO are closely related parameters that affect the environmental fate and potential ecological impacts of QD and MO nanomaterials. We also hypothesize that although some nanomaterials have very low water solubilities, the presence of NOM may increase their affinity for water and change their biodegradability and transport behavior in the environment.
To achieve these goals, we will prepare and characterize QD and MO with varying hydrophobicity of surface capping, and with varying particle size. We will examine the interactions of these engineered nanomaterials with model humic and fulvic acids using various spectroscopic techniques to monitor the changes in the vibrational spectra of the NOM upon surface binding. Further, we will conduct a series of experiments to measure the binding constants of QD and MO with humic and fulvic acids using capillary electrophoresis. Soil columns will be used to determine the influence of NOM on the leaching potential and stability of QD and MO; the amount of nanomaterials will be quantified in both the leachate and in the subsections of the soil column. Laboratory-scale experiments will be conducted to assess the amount of toxic metals that can be potentially released from QD and MO during biological wastewater treatment, and to measure bioconcentration factors of QD and MO in earthworms.
The proposed work will provide, for the first time, data on the environmental stability and mobility of QD and MO as a function of their formulation. The unique application of capillary electrophoresis in measuring binding constants of nanoparticles with NOM could provide a predictive tool in determining leaching potential of nanoparticles in the environment. Information on the biodegradation and bioaccumulation of QD and MO will help the regulatory agencies and industries to design effective treatment systems in advance, to prevent the exposure of humans, fish, and wildlife to potentially toxic nanomaterials.