Distribution and risk assessment of antibiotics under water level fluctuation in the riparian zone of the Hanjiang River

Occurrence profiling, risk assessment, and correlations of antimicrobials in surface water and groundwater systems in Southwest Nigeria

The presence of antimicrobials in water has grown into a major global health concern. This study thus focused on the presence, ecological implications, and potential health risks associated with nine antimicrobials: five antibiotics (ampicillin, chloramphenicol, ciprofloxacin, metronidazole, and tetracycline) and four parabens (methylparaben, ethylparaben, propylparaben, and butylparaben) in surface water and groundwater samples collected from three Southwestern States in Nigeria (Osun, Oyo, and Lagos States). These antimicrobials were widely detected across the three States with ciprofloxacin being the most dominant having maximum average concentrations of 189 μg L-1 and 319 μg L-1 in surface water and groundwater respectively. The range of average concentrations of antibiotics in surface water are 47.3-235 μg L-1 (Osun), 27.9-166 μg L-1 (Oyo) and 52.1-159 μg L-1 (Lagos). For groundwater, it is 35.3-180 μg L-1 (Osun), 26.5-181 μg L-1 (Oyo) and 32.3-319 μg L-1 (Lagos). The average concentrations of all parabens were 32.4-153 μg L-1, 53.4-80.1 μg L-1, and 83.2-132 μg L-1 for surface water and 46.7-55.7 μg L-1, 53-117 μg L-1, and 62.4-118 μg L-1 for groundwater in Osun, Oyo, and Lagos States respectively. Methylparaben was most frequently detected paraben with average concentrations of 153 μg L-1 and 117 μg L-1 in surface water and groundwater respectively. The measured environmental concentrations of these antimicrobials pose a significant ecological risk while those of ciprofloxacin and ampicillin pose a high health risk to all population groups studied. The average concentrations of antibiotics investigated in this study exceeded their threshold values for Predicted No-Effect Concentrations (PNEC) associated with resistance selection, except for tetracycline.

Antibiotics and antibiotic resistance genes in the water sources of the Wuhan stretch of the Yangtze River: Occurrence, distribution, and ecological risks

Given the ubiquitous detection of antibiotics and antibiotic resistance genes (ARGs) in waterbodies worldwide and increasing public attention to water resource safety, this study investigated the presence of antibiotics and ARGs in the water sources of the Wuhan stretch of the Yangtze River (YR) as well as potential ecological risks. In this study, 15 antibiotics and 10 ARGs in a source of drinking water were analyzed using solid-phase extraction-ultra performance liquid chromatography-mass spectrometry technology (SPE-UPLC-MS/MS) and real-time fluorescence quantitative polymerase chain reaction (qPCR). Fourteen antibiotics were detected in the samples from 18 water sources, with the highest concentration detected for tetracycline, reaching up to 1708.33 ng/L. The detection rates of norfloxacin, enrofloxacin, ofloxacin, tetracycline, and roxithromycin were 100%. The concentrations of antibiotics were highest in She Shui, followed by the Wuhan stretch of the lower reaches of the YR, whereas the lowest concentrations were found in the Wuhan stretch of the upper reaches of the YR which were approximately equal to those in the Han River (HR). Ofloxacin and roxithromycin presented a substantial threat to aquatic organisms with high sensitivity at the majority of the sampling sites. The overall abundance of ARGs was notably greater in the lower reaches of the YR compared with the upper reaches and the HR. The highest absolute abundance was observed for sulfa ARGs. Integron intl1 strongly correlated with sul1, sul2, ermB, and qnrS, and antibiotics, strongly correlated with multiple ARGs, suggesting that antibiotics and ARGs are present in water sources in Wuhan and may present a plausible hazard to both human and ecological well-being. Hence, regulating the spread and dissemination of antibiotics and ARGs in the environment is imperative. The findings of this research offer significant insights into the stewardship and safeguarding of aquatic reserves in the Wuhan stretch of the YR.