Contamination Of Antibiotics In Intensive Mariculture Areas

Antibiotic pollution has become a hot and difficult problem in the global environment.Aquaculture as one of the most widely used fields of antibiotics,have caused environmental pollution,ecological environmental effects and food safety problems.This study chose Sansha Bay,a typical intensive mariculture in Ningde,southeast of China as a study area,and selected 48 kinds of antibiotics from five types as the target.We studied the contamination,temporal and spatial characteristics of antibiotics in the environment,and antibiotic residues in Larimichthys crocea at different growth stages and its relationship with environmental concentrations,the health risk of croaker was also been evaluated.It provides scientific basis and data support for regional antibiotic management and health risk assessment.The contents of this study mainly include the following points:(1)Several kinds of antibiotic residues were detected in surface water and sediment samples in Sansha Bay,the overall concentration of antibiotics was at ng/L and ng/g levels.The total concentration of antibiotics was higher in winter(163.92～465.42 ng/L)than in spring(2.60～109.14 ng/L)in surface water.The composition of antibiotics was also varied in different seasons,sulfonamides and quinolones were the main antibiotics in spring,accounting for 55.34%and 38.69%of the total antibiotics burden,quinolones and tetracyclines were the main antibiotics,accounting for 29.83%and 31.11%of the total burden in winter,respectively.Higher concentration of antibiotics were observed in aquaculture areas,indicating that aquaculture activities had an important effect on antibiotic residues in surface water.When compared with other breeding areas in China the total concentration of antibiotic residues in surface water of Sansha Bay area was at a medium level,but the concentration of quinolones was higher.The concentration of antibiotics in winter(21.56～930.27 ng/g)was higher than spring(2.25～139.41 ng/g)in sediment samples.Quinolones was the predominant antibiotics in different seasons,followed by tetracyclines>macrolides>chloramphenicols and sulfonamides.Based on the use and discharge of antibiotics in Sansha Bay area,the quinolones and tetracyclines detected in sediment samples were mainly from fishery,while the macrolides was mainly affected by land source input.Compared with other aquaculture areas in China,the antibiotic residues in the sediments of Sansha Bay was at a medium level,but the concentrations of sulfonamides and macrolides were relatively low.(2)The composition changes of antibiotics in different growth stages of Larimichthys crocea in Sansha Bay were tracked and analyzed.Antibiotic residues were prevalent in the surface water of aquaculture cages,the total concentration of antibiotics was 63.40～1033.71 ng/L and tetracyclines were the most important detected substances.The total concentration of antibiotics was 7.91～36.56 ng/g in sediment.Quinolones were the main detected substances.Antibiotic residues were also been detected in fish tissues,and the total concentration of antibiotics was higher in liver(7.43～636.79 ng/g)than in muscle(3.94～321.08 ng/g).Quinolones was the main substances in muscle and composition of antibiotics varied greatly at different stages in fish liver.Due to the differences in antibiotic usage and metabolism of fish body,antibiotics residues varied in fish tissues at different stages,which were specifically manifested as the trends:breeding stage>species overwintering stage>adult fish culture stage.(3)Quinolones were the strongest biogenic antibiotics in the tissues of Larimichthys crocea,followed by tetracyclines,while macrolides showed no bioenrichment behavior in fish tissues.In addition,bioenrichment behavior of antibiotics was easy to be observed in the stage of fish breeding and species overwintering,but not in the stage of adult fish cultivation.In comparison with the regulations of the department of agriculture on antibiotic residues,the antibiotic residues in aquatic products meet the national standards in all months except February.Of all the antibiotics detected,enoxacin had the highest HQ value(0.12～0.14),which showed moderate health risk to children,adolescents and adults of both sexes,the remaining classes of antibiotics are all at low risk.