Occurrence and removal of sulfonamide antibiotics and antibiotic resistance genes in conventional and advanced drinking water treatment processes

摘要

Sulfonamides (SAs) and sul antibiotic resistance genes (ARGs) have been extensively detected in drinking water sources and warrant further studies on the removal of them in different drinking water treatment processes (DWTPs). The prevalence of 13 SAs, sul1, su12 and class I integrase gene intll in conventional and advanced processes was investigated using HPLC-MS/MS and real-time quantitative PCR (qPCR), respectively. The most abundant SA was sulfamethoxazole, with the maximum concentration of 67.27 ng/L. High concentration of sulfamethoxazole was also measured in finished water in both conventional (22.05 ng/L) and advanced (11.24 ng/L) processes. Overall, the removal efficiency of advanced process for each SA was higher than that of conventional process, except for sulfameter. The absolute concentrations of sul1, sul2 and intll in raw water ranged from L8 x 10(3) to 2.4 x 10(5) gene abundance/mL. After treatment, the residual sul ARGs and intil in finished water still remained at 10(2) - 10(4) gene abundance/mL. Conventional treatment units, including flocculation/sedimentation/sand filtration, played a more important role in removing sul1, sul2 and intll than oxidation (chlorination or ozonation) and granular activated carbon filtration treatments. Based on this work, more investigations are needed to help improve the removal of both antibiotics and ARGs in DWTPs.