title: Concomitant uptake of antimicrobials and Salmonella in soil and into lettuce following wastewater irrigation.
abstract: The use of wastewater for irrigation may introduce antimicrobials and human pathogens into the food supply through vegetative uptake. The objective of this study was to investigate the uptake of three antimicrobials and Salmonella in two lettuce cultivars. After repeated subirrigation with synthetic wastewater, lettuce leaves and soil were collected at three sequential harvests. The internalization frequency of Salmonella in lettuce was low. A soil horizon-influenced Salmonella concentration gradient was determined with concentrations in bottom soil 2 log CFU/g higher than in top soil. Lincomycin and sulfamethoxazole were recovered from lettuce leaves at concentrations as high as 822 ng/g and 125 ng/g fresh weight, respectively. Antimicrobial concentrations in lettuce decreased from the first to the third harvest suggesting that the plant growth rate may exceed antimicrobial uptake rates. Accumulation of antimicrobials was significantly different between cultivars demonstrating a subspecies level variation in uptake of antibiotics in lettuce.
authors.affiliation: University of Nebraska-Lincoln, Department of Civil Engineering, N104 SLNK, Lincoln, NE 68588-0531, USA.
authors.forename: J Brett
authors.initials: JB
authors.lastname: Sallach
authors.affiliation: University of Nebraska-Lincoln, Department of Civil Engineering, N104 SLNK, Lincoln, NE 68588-0531, USA.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: University of Nebraska-Lincoln, Department of Agronomy and Horticulture, 377N PLSH, Lincoln, NE 68583-0724, USA. Electronic address: lhodges1@unl.edu.
authors.forename: Laurie
authors.initials: L
authors.lastname: Hodges
authors.affiliation: University of Nebraska-Lincoln, Water Sciences Laboratory, 202 Water Sciences Laboratory, 1840 North 37th Street, Lincoln, NE 68583-0844, USA. Electronic address: dsnow1@unl.edu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Snow
authors.affiliation: University of Nebraska-Lincoln, Department of Civil Engineering, N104 SLNK, Lincoln, NE 68588-0531, USA. Electronic address: xuli@unl.edu.
authors.forename: Xu
authors.initials: X
authors.lastname: Li
authors.affiliation: University of Nebraska-Lincoln, Department of Civil Engineering, 203B Peter Kiewit Institute, Omaha, NE 68182-0178, USA. Electronic address: sbartelt2@unl.edu.
authors.forename: Shannon
authors.initials: S
authors.lastname: Bartelt-Hunt
mesh_terms: D057914:Agricultural Irrigation / Q000379:methods*; D000890:Anti-Infective Agents / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D018545:Lactuca / Q000378:metabolism* / Q000382:microbiology; D018515:Plant Leaves; D012475:Salmonella / Q000254:growth & development*; D012987:Soil; D012988:Soil Microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology
chemical_list: D000890:Anti-Infective Agents; D012987:Soil; D062065:Wastewater
keywords: Antimicrobial; Lettuce; Salmonella; Uptake; Wastewater irrigation