RESPONSE OF SOIL ENZYMES TO TWO ANTIBIOTICS: POLYMYXIN B AND PENICILLIN G.

The increased use of antibiotics has raised concern regarding the environmental impacts of antibiotic residues in soil. In this study, we performed a laboratory experiment to compare the effect of two antibiotics: polymyxin B and penicillin G on the activity of alkaline phosphatase, acid phosphatase, dehydrogenases, and urease, in sandy loam and loamy sand. Antibiotics were applied to soil samples at the dosages: 2, 20, and 200 mg/kg DM. Soil without antibiotics was used as a control sample. The results showed that the contamination of soil with antibiotics affects the soil enzymes. Polymyxin B caused greater changes in enzyme activities than that of penicillin G. Moreover, greater changes in soil enzyme activities were observed in loamy sand than in sandy loam. Phosphatases were the most sensitive to the soil contamination with antibiotics. Principal component analysis showed that dehydrogenases were the most negatively correlated with PC1. [ABSTRACT FROM AUTHOR]