title: Transport of three veterinary antimicrobials from feedlot pens via simulated rainfall runoff.
abstract: Veterinary antimicrobials are introduced to wider environments by manure application to agricultural fields or through leaching or runoff from manure storage areas (feedlots, stockpiles, windrows, lagoons). Detected in manure, manure-treated soils, and surface and ground water near intensive cattle feeding operations, there is a concern that environmental contamination by these chemicals may promote the development of antimicrobial resistance in bacteria. Surface runoff and leaching appear to be major transport pathways by which veterinary antimicrobials eventually contaminate surface and ground water, respectively. A study was conducted to investigate the transport of three veterinary antimicrobials (chlortetracycline, sulfamethazine, tylosin), commonly used in beef cattle production, in simulated rainfall runoff from feedlot pens. Mean concentrations of veterinary antimicrobials were 1.4 to 3.5 times higher in surface material from bedding vs. non-bedding pen areas. Runoff rates and volumetric runoff coefficients were similar across all treatments but both were significantly higher from non-bedding (0.53Lmin(-1); 0.27) than bedding areas (0.40Lmin(-1); 0.19). In keeping with concentrations in pen surface material, mean concentrations of veterinary antimicrobials were 1.4 to 2.5 times higher in runoff generated from bedding vs. non-bedding pen areas. Water solubility and sorption coefficient of antimicrobials played a role in their transport in runoff. Estimated amounts of chlortetracycline, sulfamethazine, and tylosin that could potentially be transported to the feedlot catch basin during a one in 100-year precipitation event were 1.3 to 3.6ghead(-1), 1.9ghead(-1), and 0.2ghead(-1), respectively. This study demonstrates the magnitude of veterinary antimicrobial transport in feedlot pen runoff and supports the necessity of catch basins for runoff containment within feedlots.
authors.affiliation: Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta T1J 4B1, Canada. Electronic address: Srinivas.Sura@ec.gc.ca.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Sura
authors.affiliation: Alberta Innovates Technology Futures, Edmonton, Alberta T6N 1E4, Canada. Electronic address: Dani.Degenhardt@albertainnovates.ca.
authors.forename: Dani
authors.initials: D
authors.lastname: Degenhardt
authors.affiliation: Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan S7N 0X2, Canada. Electronic address: Allan.Cessna@agr.gc.ca.
authors.forename: Allan J
authors.initials: AJ
authors.lastname: Cessna
authors.affiliation: Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta T1J 4B1, Canada. Electronic address: Francis.Larney@agr.gc.ca.
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Larney
authors.affiliation: Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta T1J 4B1, Canada. Electronic address: Andrew.Olson@agr.gc.ca.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Olson
authors.affiliation: Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta T1J 4B1, Canada. Electronic address: Tim.McAllister@agr.gc.ca.
authors.forename: Tim A
authors.initials: TA
authors.lastname: McAllister
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000032:analysis*; D002751:Chlortetracycline / Q000032:analysis; D004784:Environmental Monitoring; D008372:Manure / Q000032:analysis; D011891:Rain; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D013418:Sulfamethazine / Q000032:analysis; D015645:Tylosin / Q000032:analysis; D019155:Veterinary Drugs / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D000890:Anti-Infective Agents; D008372:Manure; D012987:Soil; D012989:Soil Pollutants; D019155:Veterinary Drugs; D014874:Water Pollutants, Chemical; D013418:Sulfamethazine; D002751:Chlortetracycline; D015645:Tylosin
keywords: Antimicrobial transport; Beef cattle manure; Chlortetracycline; Feedlot pen runoff; Runoff export coefficient; Sulfamethazine; Tylosin; Veterinary antimicrobials; Volumetric runoff coefficient