CHEEC Seed Grants: FY 2005

Adsorption of Environmental Pollutants Using Nanocrystalline Zeolites
S. Larsen, Department of Chemistry, University of Iowa

Development of molecular techniques for the detection of vinyl chloride degrading bacteria in the environment 
T. Mattes, Department of Civil and Environmental Engineering, University of Iowa

Passive Sampling of Ambient Air Particulate Matter 
T. Peters, D. Ott, Department of Occupational and Environmental Health, University of Iowa

White-tailed Deer, Mosquitoes, and the Ecology of West Nile Virus 
J. Gill, K. Rainwater, University Hygienic Laboratory, University of Iowa

 


Adsorption of Environmental Pollutants Using Nanocrystalline Zeolites 
Investigator: S. Larsen, Department of Chemistry, University of Iowa 
Zeolites are crystalline, aluminosilicate molecular sieves with pores of molecular dimensions that are widely used as catalysts, adsorbents and ion exchangers. Nanocrystalline zeolites are synthetic zeolites with discrete, uniform crystals of less than 100 nm in size. Nanocrystalline zeolites have increased surface areas relative to commercial, micron-sized zeolites. In our laboratory, we have synthesized several different zeolites (ZSM-5, Y and silicalite) with crystal sizes of approximately 20 nm. These materials have enhanced adsorption capacities due to the increased surface areas relative to micron-sized zeolites. The nanocrystalline zeolite external surface can be functionalized to tailor its properties for adsorption of pollutants in different environments. The hypothesis of the proposed study is that nanocrystalline zeolites will be effective adsorbents for volatile organic compounds (formaldehyde, benzene and trichloroethylene) and inorganic oxyanions (chromate, arsenate, selenate). These environmental pollutants have been linked to many health problems due to their toxicity.                                                                                                                                                                                                                                                                  Publication:  Petushkov A, Intra J, Graham JB, Larsen SC, Salem AK. Effect of crystal size and surface functionalization on the cytotoxicity of silicalite-1 nanoparticles. Chem Res Toxicol. 2009 22(7):1359-68.

Development of molecular techniques for the detection of vinyl chloride degrading bacteria in the environment 
Investigators: T. Mattes, Department of Civil and Environmental Engineering, University of Iowa 
Vinyl chloride (VC), a known human carcinogen, neurotoxin and common groundwater contaminant, represents a serious threat to public health if VC contaminates drinking water source zones. The presence and activity of VC-degrading bacteria at a contaminated site is a crucial line of evidence for demonstrating natural attenuation and a subsequent reduction of risk to human health. Because VC-degrading bacteria appear to be a specialized, non-ubiquitous subset of the ubiquitous ethene-degrading bacteria, there is currently no sequence-based method to distinguish an ethene-degrading bacterium from a VC-degrading bacterium. This is a serious shortcoming for site assessment and bioremediation studies. To alleviate this shortcoming and enhance our ability to compete for external research support, we propose to sequence VC and ethene biodegradation genes from several VC-degrading and solely ethene-degrading bacteria. This work will generate a gene database to facilitate molecular probe design and will shed light on possible VC acclimation mechanisms.                                                                                                                                                                                                                                                                                      Publication:  Jin YO, Mattes TE. Adaptation of aerobic, ethene-assimilating Mycobacterium strains to vinyl chloride as a growth substrate. ES&T 2008 42:4784-4789.

Passive Sampling of Ambient Air Particulate Matter 
Investigators: T. Peters, D.Ott, Department of Occupational and Environmental Health, University of Iowa 
Adverse health outcomes have been associated with exposure to atmospheric particulate matter (PM). National Ambient Air Quality Standards aim to protect Americans from these exposures through state-run monitoring networks; states must reduce particle concentrations when they exceed national standards. Costs associated with traditional samplers severely limit the number of monitoring sites, which hampers efforts to identify and control key sources of particles. The work proposed here will adapt a new passive sampler for its use in PM networks via three tasks: [i] design an outdoor housing for the new sampler; [ii] assess its precision and accuracy for concentrations typical of the atmosphere; and [iii] use these samplers to identify any key sources of particulate within Iowa City. Passive samplers are substantially more economical than traditional samplers; thus, this work will enable more observations so that actions taken by states to reduce particle concentrations will have a greater likelihood of success.                                                                                                                                                                                                                                                                                                                                                                  Publication:  Ott DK, Kumar N, Peters TM. Passive sampling to capture spatial variability in PM 10-2.5 Atmospheric Environment 2007, doi:10.1016/j.atmosenv.2007.09.058

White-tailed Deer, Mosquitoes, and the Ecology of West Nile Virus 
Investigators: J. Gill, K. Rainwater, University Hygienic Laboratory, University of Iowa
The rapid spread of West Nile Virus (WNV) in the United States has emphasized public health officials concerns about emergent zoonotic diseases. As deer populations continually expand in neighborhoods and areas of significant human activity, Iowans are at an increased risk of several zoonotic infections. We propose a pilot study of over one thousand white-tailed deer (WTD) and several thousand mosquitoes 1) to determine exposure of WTD to WNV, 2) to investigate whether WTD serve as a competent, peri-domestic reservoir for WNV, and 3) to determine anthropophilic mosquitoes that serve as bridge vectors to humans. Serologic testing of deer sera, identification of mosquito host blood, and testing of mosquitoes by polymerase chain reaction will be performed to document risk of Iowans to potential WNV infection. We believe these results will lead to improved surveillance, prevention, and control methods of WNV infections in humans.