Bioaccumulation and Mass Balance Analysis of Veterinary Antibiotics in an Agricultural Environment

Veterinary antibiotics (VAs) released into the environment are a concern because of the possibility for increasing antibiotic-resistance genes. The concentrations of six VAs, chlortetracycline, oxytetracycline, tetracycline, sulfamethazine, sulfamethoxazole, and sulfathiazole, in manure-based compost, soil, and crops were measured using liquid chromatography-tandem mass spectrometry. Mass balance analysis was conducted based on the measured antibiotic concentration, cultivation area, and amount of manure-based compost applied. The result showed that the detected mean concentration of VAs ranges was 3.52 similar to 234.19 mu g/kg, 0.52 similar to 13.08 mu g/kg, and 1.05 similar to 39.57 mu g/kg in manure-based compost, soil, and crops, respectively, and the substance of VAs detected in different media was also varied. Mass balance analysis showed that the VAs released from the manure-based compost can remain in soil (at rates of 26% to 100%), be taken up by crops (at rates of 0.4% to 3.7%), or dissipated (at rates of 9% to 73%) during the cultivation period. Among the six VAs, chlortetracycline and oxytetracycline mainly remained in the soil, whereas sulfamethoxazole and sulfathiazole were mainly dissipated. Although we did not verify the exact mechanism of the fate and distribution of VAs in this study, our results showed that these can vary depending on the different characteristics of VAs and the soil properties.

Automated summary

The study found that the presence of veterinary antibiotics (VAs) in the environment is a concern due to the potential for increasing antibiotic resistance genes. The concentrations of six VAs in manure-based compost, soil, and crops varied, and mass balance analysis revealed that VAs can remain in soil, be taken up by crops, or dissipate during cultivation. Among the six VAs, different fate and distribution patterns were observed, with some remaining in soil and others dissipating.