CHEEC Seed Grants: FY 2000

Characteristics of BTEX Plumes in Iowa: A survey of Plume Dimensions and Stability 
PJ Alvarez, Department of Civil and Environmental Engineering, The University of Iowa

Comparison of Biological and Chemical Endpoints for Evaluating the Success of Phytoremediation of Pesticide-Contaminated Soil 
J Coats, J Belden, Department of Entomology Pesticide Toxicology Laboratory, Iowa State University

Enhancing Bioaerosol Exposure Assessment: A Comparison of Three Commercially Available Impingers 
T Pearce, P Thorne, Department of Occupational and Environmental Health, The University of Iowa

Exploratory and Experimental GIS Studies of the Association of Rural Ambient Air Quality with Asthmatic Children of a Small Area Cohort 
G Rushton, E Svendsen, Department of Geography, P Thorne, Department of Occupational and Environmental Health, The University of Iowa

The Role of Surface Precipitates in Remediation Technologies Based on Iron Metal 
M Scherer, Department of Civil and Environmental Engineering, The University of Iowa

Changes in Rhizosphere Microbial Populations and Arsenic Speciation as a Result of Phytoremediation of Contaminated Soils 
J Simeonsson, Department of Chemistry, P Alverez, Department of Civil and Environmental Engineering, The University of Iowa

Reactivity of Disinfection By-Products with Distribution System Pipe Deposits and Cast Iron 
R Valentine, M Scherer, Department of Civil and Environmental Engineering, University of Iowa

 


Characteristics of BTEX Plumes in Iowa: A survey of Plume Dimensions and Stability
Investigator: PJ Alvarez, Department of Civil and Environmental Engineering, The University of Iowa 
Groundwater contamination by petroleum product releases is a common threat to public health. Contaminant plume dimensions and stability are important to characterize for risk management because they determine the area of influence and the potential duration of exposure. This project will analyze data from about 600 sites to identify central tendencies, variability, and regional trends of hydrocarbon plume characteristics. The data will be obtained from the Iowa Department of Natural Resources electronic database. Statistical analysis will be conducted to answer important questions, such as: What is a typical 'safe' distance down gradient of the source, beyond the reach of the plume? Technical Report Available.

Comparison of Biological and Chemical Endpoints for Evaluating the Success of Phytoremediation of Pesticide-Contaminated Soil
Investigators: J Coats, J Belden, Department of Entomology Pesticide Toxicology Laboratory, Iowa State University 
The study will evaluate several biological and chemical endpoints as possible indicators of remediation success as compared to traditional chemical analysis. Endpoints to be evaluated will include: chemical analysis of body residues in exposed earthworms, toxicity of soil to lettuce (germination and growth), toxicity of aqueous soils extractions to Daphnia magna, chemical analysis of aqueous soil extractions, toxicity of soil column leachate to D. magna, chemical analysis of soil column leachate, and analysis of soil by rigorous solvent extraction. The proposed endpoints will provide measurements of terrestrial and aquatic toxicity along with thorough evaluation of the pesticides leaching potential. At the end of the study, a better understanding of how phytoremediation may affect bioavailability and the presence of toxic metabolites will be gained.

Publication:  Henderson KL, Belden JB, Zhao S, Coats JR; Phytoremediation of Pesticide Wastes in Soil. Z Naturforsch C. 2006; 61(3-4):213-221

Enhancing Bioaerosol Exposure Assessment: A Comparison of Three Commercially Available Impingers Investigators 
T Pearce, P Thorne, Department of Occupational and Environmental Health, The University of Iowa 
Currently there are no definitions of acceptable exposure or enforceable standards to hazardous bioaerosols that are associated with a high burden of morbidity and mortality. Emerging airborne diseases intensifies the importance of improving methodology for bioaerosol exposure assessment. Improvements will require characterizing the capabilities and limitations of existing methodology and the development of new techniques. Impinger samplers hold promise for current assessments, as they possess high collection efficiency and sample analysis flexibility. The study seeks to characterize the collection efficiencies of three commercially available impinger samplers using culture based and non-culture based methods of analysis. Information and data generated is intended to advance bioaerosol assessment in the present and improve methodology in the future.

Exploratory and Experimental GIS Studies of the Association of Rural Ambient Air Quality with Asthmatic Children of a Small Area Cohort
Investigators: G Rushton, E Svendsen, Department of Geography, P Thorne, Department of Occupational and Environmental Health, The University of Iowa 
Ambient air pollution sources are one of the potential environmental exposure sources that have been suggested to influence childhood asthma. Though asthma research has been done in many cities, little is known about asthma risk factors in rural populations. This study will both explore and experiment on the distributions of asthma cases and controls from the Keokuk County Rural Health Study in the context of neighboring point source air polluters such as hog-lots and grain mills. Space, time, space-time interaction, space-time clustering, and spatial regression analyses will be performed using recently developed spatial statistical tools. The hypothesis will be tested that asthma cases are found to be significantly closer to point source air polluters within the Keokuk Country area than the control group.

The Role of Surface Precipitates in Remediation Technologies Based on Iron Metal
Investigator: M Scherer, Department of Civil and Environmental Engineering, The University of Iowa 
Recent work on remediation of oxidized chemicals with permeable reactive barriers (PRBs) containing iron metal (Fe0) has shown that remediation performance is strongly affected by the layers of precipitates that form on the iron surface over time, and that the quantity and composition of these precipitates vary greatly depending on the composition of the groundwater. Despite the enormous success of Fe0 PRBs, the identity and significance of this surface precipitate is still unclear. This research proposes to develop a series of experimental protocols to characterize the composition of the surface precipitates forming in the Fe0 PRBs and evaluate how variations in solution chemistry are linked to changes in the precipitate coatings, which then enhance or inhibit PRB performance.

Publication:  Alowitz MJ, Scherer MM; Kinetics of nitrate, nitrite, and CR(VI) reduction by iron metal. Environ Sci Technol. 2002; 36(3):299-306

Changes in Rhizosphere Microbial Populations and Arsenic Speciation as a Result of Phytoremediation of Contaminated Soils
Investigators: J Simeonsson, Department of Chemistry, P Alverez, Department of Civil and Environmental Engineering, The University of Iowa 
This study is designed to evaluate whether the speciation of soil arsenic (As) is altered as a result of phytoremediation and whether microbial communities in the root zone are associated with changes in speciation. It is also of interest to determine whether microbial communities are associated with the volatilization of As compounds. Plant growth experiments will be conducted in controlled environments. Poplar saplings will be grown while exposed to varying amounts of soil-based As. Changes in speciation and volatilization will be investigated through measurements of As in soil, plant and air samples collected from the test chambers. Microbial populations in the rhizosphere of the saplings will be enumerated based on their ability to change the speciation of soil As.

Reactivity of Disinfection By-Products with Distribution System Pipe Deposits and Cast Iron 
Investigators: R Valentine, M Scherer, Department of Civil and Environmental Engineering, University of Iowa 
This project will investigate reactions that could potentially reduce Disinfection By-Products (DBPs) in distribution systems. The researchers hypothesize that the dominant abiotic loss pathways involve reactions with pipe deposit material and with nascent cast iron, especially under reduced conditions. The objective of this research is to characterize the reactivity of selected DBPs with model and collected pipe deposit material, and with cast iron. A special emphasis will be on reactions with unidentified organic halide containing compounds, referred to as unidentified Total Organic Halogen uTOX. This material generally accounts for over 75% of the total halogen incorporated into organic matter.

Publication: Vikesland PJ, Valentine RL; Iron oxide surface-catalyzed oxidation of ferrous iron by monochloramine: implications of oxide type and carbonate on reactivity. Environ Sci Technol. 2002; 36(3):512-519