Bioavailability of Metallic Nanoparticles and Heavy Metals in LandfillsEPA Grant Number: R833893
Title: Bioavailability of Metallic Nanoparticles and Heavy Metals in Landfills
Investigators: Hu, Zhiqiang , Elias, Dwayne A. , Wall, Judy D.
Institution: University of Missouri - Columbia
EPA Project Officer: Lasat, Mitch
Project Period: April 1, 2009 through March 31, 2012
Project Amount: $399,262
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
The objectives of this research are to determine bioavailability of nanoparticles and heavy metal species in bioreactor landfills as compared to traditional municipal solid waste landfills; and to elucidate the mechanisms governing bioavailability as well as the mode of antimicrobial action by nanoparticles. In order to accomplish these objectives, three hypotheses will be tested: 1) nanoparticles that can leach into the water from landfill runoff are bioavailable; 2) nanoparticles enhance heavy metal bioavailability and leachate toxicity; and 3) the bioavailability of nanoparticles and heavy metals is higher in bioreactor landfills than in traditional landfills.
Silver and titanium dioxide nanoparticles will be used for bioavailability studies because of their wide applications and risk concern in the environment. Bioavailability inferred from biochemical methane potential (BMP) and leachate toxicity tests will be evaluated throughout the project. The BMP rates will be monitored using real-time anaerobic flow modules in the presence and absence of nanoparticles. Leachate toxicity will also be evaluated by a rapid and high throughput time-resolved fluorescence microrespirometry, with confirmation of the findings via the metal speciation (Ag, Ti, Cu, Zn, Ni, Cd, Pb, Cr) analysis by inductively coupled plasma mass spectrometry (ICP-MS). The bioavailability and toxicity of nanoparticles will be correlated with their size, shape, as well as the changes of dominant microbial community using quantitative polymerase chain reactions (qPCR). Research results including Ag nanoparticle transformation, enhanced metal availability in the presence of TiO2, and the changes of syntrophic microbial communities in lab-scale bioreactors will be compared with those in traditional landfill reactors via student’s t tests. The microbial-nanoparticle interactions will be visualized and determined using high resolution environmental scanning electron microscopy and two-photon laser scanning microscopy.
The project will provide some of the first data on the bioavailability and risk assessment of metallic nanomaterials in solid waste disposal systems. Considering the unintentional release of nanomaterials through disposal to landfills, we will establish a better understanding of transport, partitioning and toxicity of nanoparticles to syntrophic anaerobic communities that are likely occurring in more than 3,000 active landfills in the U.S. that could significantly impact the environment and public health.