Distribution characteristics and ecological risk assessment of antibiotics in representative coastal rivers in Jiangsu Province
To investigate the pollution status of antibiotics in aquatic environments,a solid-phase extraction combined with liquid chromatography-tandem mass spectrometry method was used to study the distribution characteristics of 16 typical antibiotics in surface water and suspended sediment samples from representative coastal rivers(Bencha Tea Canal,Sheyang River,Suzhou Irrigation Canal,Xinyi River and Guahe River)in Jiangsu Province,China.Ecological risk assessment was conducted using risk quotient.The results showed that thirteen antibiotics were detected in the five coastal rivers with 100%detection rates for roxithromycin(RXM)and lincomycin(LIN)in both surface water and suspended sediments.The total concentrations of macrolides(MLs),sulfonamides(SAs),quinolones(QNs)and tetracyclines(TCs)in surface water were 493.91,91.79,370.93 and 58.70 ng/L,respectively.In suspended sediments,the highest mass fraction was ofloxacin(OFX)at 24.58 ng/g,followed by RXM(12.37 ng/g),with the remaining eleven antibiotics detected at mass fractions below 10 ng/g.Spatially,the antibiotics levels in surface water and suspended sediments from sampling site R2(Sheyang River)were higher than those from the other sampling sites.The partition coefficient(Kd)showed that Kd values of RXM and azithromycin(AZM)were significantly correlated with their concentrations in surface water and suspended sediments.Redundancy analysis showed that antibiotic concentration was positively correlated with conventional water quality indicators.Ecological risk assessment showed that sampling site R1(Bencha Tea Canal)had the highest combined risk quotient(Qcom)value indicating a high risk,while RXM was a potential ecological risk factor.