Abstract
To examine the residual and distributions of tetracycline antibiotics in the Weihe River, SPE-UPLC (solid phase extraction-ultra performance liquid chromatography with UV-Vis detection) was employed to analyze the oxytetracycline (OTC), chlortetracycline (CTC), and minocycline (MC) of 41 surface water and 35 sediment samples collected from main streams, tributaries, and main sewage outlets. The results showed that: (1) The order of residual levels of tetracycline antibiotics in water and sediment from high to low was the following: OTC > CTC > MC., considering the water solubilities are 313 mg/L, 630 mg/L, and 50200mg/L and octanol water partition coefficients (Kow) are 7.94, 4.16, and 1.12 for OTC, CTC, and MC, respectively. Thus, the distribution of antibiotics was not only related to the basic properties of antibiotics, but also some environmental factors. The concentrations of OTC in water and sediment were in the range of 1.56–87.89 ng/L and 6.13–45.38 ng/g (mean value of 16.13 ng/L and 20.60 ng/g), respectively; while CTC was 1.07–26.78 ng/L and 6.17–32.29 ng/g (mean value of 4.96 ng/L and 14.48 ng/g), respectively; and MC was 0.28–12.35 ng/L and 4.80–29.74 ng/g (mean value of 1.70 ng/L and 12.96 ng/g), respectively. There were maximum concentrations in all sewage outlets. Compared with other areas in China, tetracyclines residual in the Weihe river were at a medium level; (2) in spatial distribution, the levels of tetracyclines in water and sediment from the middle and upper reaches were higher than the lower reaches. Meanwhile, the sewage outfalls and livestock farm waste water discharge appeared to be the main sources of tetracycline antibiotics in the Weihe River; (3) ecological risk assessment revealed that in main streams and tributaries, OTC and CTC may be at a low ecological risk level; while in sewage outfalls, they may represent a medium ecological risk level.
Highlights
Antibiotics can selectively impair or influence the function of other organisms at low concentrations [1]
The objectives of this study were to: (1) investigate the occurrence of three kinds of antibiotics in water and sediment in the Weihe River; (2) evaluate the spatial distribution and the sources of the antibiotics based on the correlations between environmental variables and antibiotic concentrations; (3) assess the ecologic risk of the antibiotics to the aquatic organisms according to the calculated risk quotients (RQs)
The detectable rates of three kinds of tetracycline (OTC, CTC, and MC) in 41 water samples were 100%, indicating that this type of antibiotic is widely distributed in water of the Weihe River
Summary
Antibiotics can selectively impair or influence the function of other organisms at low concentrations [1]. Antibiotics are an important pollutant in water [2]. China is the largest producer and user of antibiotics in the world. The total usage for the 36 chemicals was 92700 tons in 2013, and eventually, 53800 tons of them entered into the environment [3]. Because antibiotics were not completely degraded by organism metabolism, 25–75% in the form of a matrix or its metabolic product were released out of the body to the environment, which posed a serious threat to the ecological environment and human health [4]. Tetracyclines (TCs) are considered as one of the most widely used antibiotics because of their advantages of a broad spectrum, high quality, and low price [5].
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