Distribution Characteristics And Risk Assessment Of Quinolone Antibiotics In Qingshitan Reservoir,Guangxi

As antibiotic contamination has overused in the global environment,the problem of antibiotic contamination has raised widespread concern.So the residual characteristics of antibiotics in the research environment are of great significance.Qingshitan reservoir is an important source of water in Guilin.Before 2013,the cage culture area in the reservoir area was nearly 300,000 m~2.The domestic sewage around the reservoir area and the untreated sewage of pig farms along the coast have seriously polluted the water quality of the reservoir.However,there are few studies on antibiotic pollution in Qingshitan reservoir.So the contents,distribution characteristics and risk of quinolones antibiotics(Ofloxacin(OFX),Norfloxacin(NOR),Ciprofloxacin(CIP),Enrofloxacin(ENR))of water,sediment and fish(Cyprinus carpio,Carassius auratus,Pelteobagrus fulvidraco,Ctenopharyngodon idellus,Silurus asotus,Sinibrama macrops and Hemiculter leucisculus)were investigated in Qingshitan reservoir of Guangxi region,which was to analysis the relationship between quinolones antibiotics and quality parameters of water and sediment.The main results were listed as follow:1.Quinolone antibiotics were detected in all sampling sites of Qingshitan reservoir.The contents were:NOR<CIP<ENR<OFX(3.49~660.13 ng/L).The result of correlation analysis showed that the relationship between NOR and pH was extremely significant(P<0.01).The correlation between NOR and turbidity was significant(P<0.05).The correlation between CIP and total phosphorus(TP)concentration was significant(P<0.05).OFX and ENR had no significant relationship with water quality parameters.2.The detection rate of four quinolone antibiotics in the sediments of Qingshitan reservoir was 100%.The contents were:OFX<ENR<CIP<NOR(1.03~722.18?g/kg).There was a significant correlation between OFX and total nitrogen(TN)(P<0.05).NOR was significantly correlated with TP and total organic carbon(TOC)(P<0.05).ENR was significantly correlated with TP(P<0.05).CIP had no significant relationship with sediment quality parameters.3.The content of fish were:NOR<ENR<CIP<OFX(6.73~968.66?g/kg).The fish with the highest OFX and NOR content were Silurus asotus and Carassius auratus respectively,while CIP and ENR are Sinibrama macrops and Hemiculter leucisculus respectively.From the perspective of fish diet,carnivorous fish have the highest antibiotic content,followed by herbivorous fish and omnivorous fish have the lowest antibiotic content.From the perspective of fish habitat,the dimmersal fish have the highest antibiotic concentration,followed by the benthopelagic fish and the lowest is the pelagic fish.4.The result of ecological risk assessment showed that OFX posed a high risk in Qingshitan Reservoir while NOR,CIP and ENR were at the medium risk level.The risk quotient(RQ)values of the four quinoxatics in the sediment were all greater than 1,indicating the four quinolone antibiotics posed a high risk to the sediment environment.The result of health risk assessment showed that the health risk index of water samples at each sampling sites was similar to the maximum acceptable risk level and the main edible fish of Qingshitan reservoir had high dietary safety.