Antibiotic Uptake by Plants from Soil Applied with Antibiotic-Treated Animal Manure

Food contamination through antibiotic uptake by plants has been one of the major concerns regarding animal manure amendment to agricultural land. Antibiotic uptake by plants was tested with three veterinary antibiotics such as chlortetracycline (CTC), tylosin (TYL), and sulfamethazine (SMT) and three plants such as lettuce, tomato, and hairy vetch. Antibiotic-treated swine slurry was applied to a greenhouse soil before transplanting or sowing the plants. The treated antibiotic concentrations to the swine slurry were 22.9 mg CTC L-¹, 27.8 mg TYL L-¹, and 32.4 mg SMT L-¹. Lettuce was harvested on 64 days after transplanting and 94 days for tomato and hairy vetch. Concentrations of CTC were 3.4 ng g-¹ for lettuce and 0.7 ng g-¹ for tomato on a fresh weight basis. For TYL, 20.1 ng g-¹ from lettuce leaves and 3.0 ng g-¹ from whole hairy vetch were detected. Sulfamethazine showed greatest concentration among the three antibiotics, 63.3 ng g-¹ in lettuce leaves, 30.2 ng g-¹ in tomato fruits, and 20.9 ng g-¹ in hairy vetch. The results imply that antibiotic uptake by plants may be dependent on antibiotic type and plant type.