Antibiotic Uptake by Vegetable Crops From Manure-Applied Soils.

Since their discovery, antibiotics have been instrumental in treating infectious diseases that were previously known to kill humans and animals. However, their widespread use as feed additives in livestock production has raised concerns on the appearance of antibiotics in the food and water supply. The main pathway for these impacts is when manure containing antibiotics is land applied. This study quantified uptake of five antibiotics (chlortetracycline, tylosin, monensin, virginiamycin, and sulfamethazine) by 11 vegetable crops (spinach, lettuce, cabbage, carrots, radish, onion, garlic, tomatoes, green pepper, sweet corn and potatoes) in two different soils (clay loam, and sandy loam) that have been fertilized with fresh vs. composted turkey and hog manures and inorganic fertilizer. Results show that there is no uptake of tylosin by any crop. There was significant degradation of chlortetracycline, monensin, and virginiamycin either during composting or between the period of manure application and vegetable harvest. As a result uptake of these vegetable was generally below the limits of quantification (LOQ). In several vegetables, sulfamethazine was present above the LOQ, mainly due to slow rate of its degradation. Overall, the amount of antibiotic present in any of the vegetables was very small such that one would have to consume large quantities of vegetables to come close to the acceptable daily intake values.