Researchers Report that Antibiotics May Be Absorbing into U.S. Crops

Antibiotics Used for Cattle May End Up on Your Kitchen Table

In a new research study published in the upcoming August issue of the Journal of Environmental Quality, scientists report that antibiotics fed to livestock can accumulate in the soil that eventually is used in agriculture for domestic crops.

The study was conducted by Holly Dolliver, Academic from the Department of Soil, Water, and Climate at the University of Minnesota in Saint Paul, and Satish Gupta, Affiliate of the Research and Development Section of the Metropolitan Water Reclamation District of Greater Chicago. 

The government-sponsored research was published with the title "Sulfamethazine Uptake by Plants from Manure-Amended Soil" and was a featured presentation at the annual conference of the Soil Science Society of America (SSSA).

The study was prompted by questions regarding the impact of feeding antibiotics to livestock. This is a common practice done in the cattle industry to protect animals from environmental infections, but it is also done for non-therapeutic reasons such as growth promotion and to comply with government regulations in the management of animal materials. The research team was particularly interested in assessing if food crops that are grown in soil that has been treated with manure can incorporate antibiotics.

The study was conducted under controlled conditions in a greenhouse setting. The research team utilized an antibiotic belonging to the sulfonamide class (sulfamethazine) that is commonly used by the beef cattle industry.

The investigators used three main crops that included corn (Zea mays L), lettuce (Lactuca Sative L), and potato (Slanum tuberosum L) and were grown in a soil that had been amended with manure. The plants were then fed three different doses of sulfamethazine at a constant rate during 45 days.

The research team found that all three crops absorbed the antibiotic in considerable fashion with reported concentrations of 0.1 to 1.2 mg of antibiotic per kg of dried plant weight. All crops also exhibited a dose-dependent absorption of the antibiotic with corn and lettuce displaying the highest incorporation rates followed by potatoes.