Start Date: Sep 01, 2013
End Date: Aug 31, 2017
Losses of antibiotics and antibiotic-resistant bacteria will be determined in runoff and tile-drainage at existing field sites near Ames, Iowa; Nashua, Iowa; and Platteville, Wisconsin, which receive chicken, swine, and beef manure, respectively. The antibiotics, tylosin, tetracycline, and sulfamethazine, are the focus of the study, and these will be measured in soil and water by extraction and HPLC-MS/MS or ELISA (tetracycline). Antibiotic-resistance will be assessed by measuring antibiotic-resistance genes relevant to the focus antibiotics using qPCR methods. In addition, total and antibiotic-resistant Enterococcus will also be measured using cultural methods. In addition to the field monitoring studies, rainfall simulations will be conducted after manure application to facilitate modeling of contaminants by macropore transport. The persistence and transport of antibiotics will be modeled using the Root Zone Water Quality Model (RZWQM). The simulated rainfall experiments will provide the data for model calibration, allowing modeling of the field site data.