Rapid determination, pollution characteristics and risk evaluations of antibiotics in drinking water sources of Hainan, China

A simple method using ultra-performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-MS/MS) was developed for simultaneous determination of 50 antibiotics in drinking water sources of Hainan Province, China. Antibiotics analyzed included 23 sulfonamides, 19 quinolones, 5 tetracyclines, and 3 chloramphenicols. This new method consisted of a simple water sample preparation procedure followed by direct injection into UPLC-MS/MS, rendering the method a time-saver which required much less sample preparation time and also smaller sample volumes than conventional techniques. The method detection limits (MDLs) were 0.8–12.0 ng/L. The average recoveries ranged from 74% to 118%, with a relative standard deviation of 0.21%–11.3%. Six antibiotics, i.e., oxytetracycline (OTC), sulfamonomethoxine (SMM), sulfamethoxazole (SMX), sulfachlorpyridazine (SCP), sulfadiazine (SD), and florfenicol (FF), were detected in drinking water sources of Hainan, with the highest concentrations being 9.5, 79.7, 42.5, 14.1, 41.5, and 62.3 ng/L, respectively. The median concentrations of antibiotics ranged from 5.7 to 20.8 ng/L with 3.3%–30% detection frequencies. Based on ecological risk assessment, SMX posed a high risk to the pertinent sensitive aquatic organisms (Synechococcus leopoliensis) in two drinking water sources of Hainan. With regard to human health risk, the likelihood of posing a major risk to consumer health due to antibiotic exposure through drinking water intake was extremely low, as the risk quotients were all below 0.005. Nevertheless, the long-term ecological concerns and probable health risks of antibiotics in drinking water sources of Hainan need to be taken into consideration.