Predictive model of the fate and transport of antibiotic resistance genes in Iowa rivers
Project Period:
2017
Project Investigator(s):
K. Ikuma, C Rehmann, Department of Civil, Construction and Environmental Engineering, Iowa State University
Abstract:
The aquatic environment can act as a reservoir for antibiotic resistance genes (ARGs) and therefore contribute to human health risk. Effluent discharges from wastewater treatment plants (WWTPs) provide a constant and significant point source of environmental ARGs even in agricultural areas like Iowa. As the first step towards accurate risk assessment of the environmental dissemination of antibiotic resistance, a predictive and quantitative model of ARG persistence in Iowa rivers will be constructed and evaluated. The tasks of the proposed work involve constructing and evaluating a model that accounts for physical, chemical, and biological mechanisms of fate and transport of ARGs. Modeling will start with mass balances applied to the water column, suspended particles, sediment bed, and biofilms. The model will be evaluated by comparing with measurements in controlled laboratory microcosms and field measurements in the Ames, IA WWTP and its receiving river.
Project Results:
This project involves constructing and testing a model to predict the fate and transport of antibiotic resistance genes (ARGs) in rivers. Rivers, streams, and lakes can act as a reservoir for ARGs and therefore contribute to human health risk. Two important sources of ARGs in the environment are effluent discharges from wastewater treatment plants and runoff from agricultural areas. As a step toward developing a more comprehensive approach, the model will start by focusing on the first of the two, and it will be evaluated with results from controlled laboratory experiments and field measurements in the South Skunk River near Ames. A reliable model will help in predicting the risk to human health posed by antibiotic resistance in Iowa and elsewhere.
Important findings from this study included:
- Wastewater treatment plants contribute not just intracellular antibiotic resistance genes (iARGs) but also extracellular ARGs (eARGs).
- eARGs are an underestimated form of ARGs that can be transported through rivers and spread antibiotic resistance in environmental bacteria.
- A preliminary model of the fate and transport of ARGs in streams has been developed that incorporates both iARGs and eARGs.