Spatial-temporal Distribution and Risk Assessment of Quinolones Antibiotics in Soil of Shijiazhuang City

Abstract

Due to their importance in human medicine, quinolones (QNs), as a typical class of antibiotics, are considered to be the "highest priority critically important antimicrobials" by the World Health Organization (WHO). In order to clarify the spatial-temporal variation and risk of QNs in soil, 18 representative topsoil samples were respectively collected in September 2020 (autumn) and June 2021 (summer). The contents of QNs antibiotics in soil samples were determined using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and the ecological risk and resistance risk were calculated using the risk quotient method (RQ). The results showed that:① the average content of QNs decreased from autumn to summer (the average contents of QNs were 94.88 μg·kg-1in autumn and 44.46 μg·kg-1 in summer); the highest values appeared in the middle area. ② The average proportion of silt was without change, whereas the average proportion of clay and sand was increased and decreased, respectively; the average contents of total phosphorus (TP), ammonia nitrogen (NH4+-N), and nitrate nitrogen (NO3--N) also decreased. ③ The content of QNs was significantly correlated with soil particle size, nitrite nitrogen (NO2--N), and nitrate nitrogen (NO3--N) (P<0.05). ④ The combined ecological risk of QNs showed high risk level (RQsum>1), whereas the combined resistance risk of QNs showed medium risk level (0.1<RQsum ≤ 1). In terms of seasonal variation, RQsum showed a downward trend. Overall, the ecological risk and resistance risk of QNs in soil for Shijiazhuang City require further attention, and the risk control of antibiotics in soil should be strengthened in the future.