Dissipation and persistence of sulfonamides, quinolones and tetracyclines in anaerobically digested biosolids and compost during short-term storage under natural conditions.

This study investigated the dissipation and persistence of three groups of residual antibiotics (sulfonamides, quinolones, and tetracyclines) in anaerobically digested (AD) biosolids and compost during 28 days of storage under environmental conditions. Results showed that the total dissipation of sulfonamides was above 70%, which was higher than that of quinolones and tetracyclines. Quinolones were more persistent in compost than in AD biosolids. Similar dissipation rates in AD biosolids and compost were observed for tetracyclines. Of the four commonly used models, the availability-adjusted first-order model (AAFO) was the optimal to fit the dissipation of antibiotics, which was mainly governed by their initial concentrations, matrix pH, and the presence of organic matter and microorganisms. The half-lives of sulfonamides, quinolones, and tetracyclines in AD biosolids were 6-51 days, 1-136 days, and 15-19 days; while those were 3-21 days, 3-74 days, and 7-27 days in compost, respectively. In particular, enrofloxacin and ofloxacin were the most persistent in AD biosolids and compost, respectively. Moreover, tetracyclines were more prone to cause pseudo-persistent pollution due to their much higher residuals in comparison to sulfonamides and quinolones. Thus, both AD biosolids and compost should be further treated before their farmland applications to control antibiotic introduction to the environment.