Distribution Characteristics and Risk Assessment of Antibiotics and Polycyclic Aromatic Hydrocarbons in the Sediments of Desilting Demonstration Area in Baiyangdian Lake

A total of 22 antibiotics and 16 polycyclic aromatic hydrocarbons(PAHs) in sediments before and after desilting in typical areas(fish ponds and open water) of Baiyangdian Lake were analyzed using HPLC-MS/MS and GC/MS(high performance liquid chromatography and gas chromatography coupled with mass spectrometry), to evaluate their potentially risks to the ecological environment. The results showed that the contents of 22 antibiotics in Baiyangdian Lake sediments ranged from 0 to 52.89 ng·g-1, in which the quinolones content was the highest. After dredging treatment, the average content of antibiotics in Nanliuzhuang open water area decreased from 46.25 ng·g-1 to 9 ng·g-1(80.54% reduction), while the average content of antibiotic(19.07 ng·g-1) in Caiputai remained relatively stable. Therefore, the dredging treatment performed better in removing antibiotics from Naliuzhuang area. The total contents of 16 PAHs in sediments ranged from 23.79 ng·g-1 to 329.40 ng·g-1, in which Naphthalene was the highest(242.02 ng·g-1), while Fluoranthene was the lowest. The average content of PAHs in sediments in Nanliuzhuang decreased from 117.45 ng·g-1 to 50.49 ng·g-1 after dredging, while PAHs in Caiputai(57.98 ng·g-1) remained stable; the 57.01% reduction in PAHs in Nanliuzhuang open water indicated that dredging treatment exhibited stronger effects on PAHs variations in Nanliuzhuang compared to that of Caiputai. In addition, the ecological risk assessment showed that the risk of Enrofloxacin and Norfloxacin was high in area S2 of Nanliuzhuang open water, while PAHs exhibited relatively low ecological risk, in which the Naphthalene in area S1 of Fuhe river posed medium ecological risk while the remaining produced low ecological risks. The results indicated that quinolone antibiotics in sediments of the un-dredged area of Baiyangdian Lake should be monitored due to its higher ecological risk.