Grantee Research Project Results
The Effect of Surface Coatings on the Environmental and Microbial Fate of Nanoiron and Feoxide Nanoparticles
EPA Grant Number: R833326Title: The Effect of Surface Coatings on the Environmental and Microbial Fate of Nanoiron and Feoxide Nanoparticles
Investigators: Lowry, Gregory V. , Tilton, Robert D. , Alvarez, Pedro J. , Kim, Chris , Minkley, Edwin
Institution: Carnegie Mellon University , Chapman University , Rice University
EPA Project Officer: Aja, Hayley
Project Period: September 1, 2006 through August 31, 2009
Project Amount: $400,000
RFA: Exploratory Research: Nanotechnology Research Grants Investigating Environmental and Human Health Effects of Manufactured Nanomaterials: a Joint Research Solicitation-EPA, NSF, NIOSH, NIEHS (2006) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
Description:
Responsible use of manufactured nanomaterials in environmental applications (e.g. nanoiron) and prudent management of the associated risks requires a fundamental understanding of their mobility, bioavailability, and impacts on a wide variety of organisms. We lack a fundamental understanding of the environmental and microbial fate of nanoiron and its metal oxide oxidation product (magnetite) under environmental conditions. It is also not clear what effect surface coatings present on nanoiron (and many other NPs) will have on the rate and extent of oxidation, their mobility after reaction (and hence potential exposure risk), their interactions with soil bacteria, their effect on the soil microbial health and diversity under natural environmental conditions, or on human health.
Objective:
The study objectives are to determine the effect of common NP surface coatings on nanoiron reactivity, mobility, fate, and effect on soil bacteria. This will be accomplished by: 1) examining the fate of coated and uncoated nanoiron and Fe-oxide NPs in active and sterilized soil microcosms; 2) determining the mobility of fresh and reacted NPs in soil columns; 3) evaluating the impact of surface coatings on NP-bacteria interactions and toxicity; and 4) evaluating the changes in microbial ecology due to nanoiron and Fe-oxide NP exposure. NP mobility and fate in the environment, negative or beneficial interactions with soil bacteria, and reactivity with soil contaminants are controlled by particle surface chemistry. Adsorbed surface coatings, e.g. polymers, polyelectrolytes, and surfactants dictate the interactions of NPs with environmental media and microbes and therefore can be used to control their environmental fate and potential toxicity, and to enhance synergistic biogeochemical interactions of nanoiron with soil microorganisms such as biostimulation by cathodic hydrogen production and reductive dissolution of inert Fe(III) oxides that passivate the nanoiron surface.
Expected Results:
This project will provide fundamental information on the effects of typical NP surface coatings on the fate and mobility of nanoiron and Fe-oxide NPs after exposure under realistic environmental conditions, and the impact of these surface coatings on microbial processes important to site remediation and ecosystem health. This will enable the synthesis and use of ecofriendly surface-coated nanoiron and Fe-oxide NPs, and enable rational risk-based decision making regarding their production, use, and disposal.