Study On The Ecotoxicity Of Quinolone Antibiotics In Aquatic Food Chain

In the past 50 years,antibiotics have been widely used in medical treatment of human health,animal breeding and husbandry production.Due to limited by the metabolize ability of target organisms to antibiotics,a large number of antibiotics were released into the water environment,so caused a very serious problem of water environment pollution.By the processes such as rainfall,urban sewage and so on,all antibiotics residues in the terrestrial environment will eventually enter the aquatic ecosystem,and antibiotics will be the most harmful for aquatic organisms.Therefore,the dangerous of aquatic ecosystem caused by the enrichment and transmission of antibiotics in the aquatic food chain had been attracted more and more attention.(1)Through the ecotoxicity tests of enrofloxacin and ciprofloxacin to four kinds of planktonic algae(Chlorella vulgaris,Scenedesmus quadricauda,Tetradesmus obliquus,Microcystis aeruginosa),the EC50 values of these four microalgae were explored,and the effect of microcystins(MC)production of M.aeruginosa under the stress of these two quinolone antibiotics was also researched;(2)Through the ecotoxicity tests of enrofloxacin and ciprofloxacin to Daphnia magna and Quasipaa spinosa tadpoles,the LC50 values and safe concentration(SC)of D.magna and Q.spinosa tadpoles were explored,And the effects of enrofloxacin and ciprofloxacin on the growth parameters of large mackerel population were studied by chronic toxicity test;(3)Through setting up two short food chains of C.vulgaris-D.magna and C.vulgaris-Q.spinosa tadpoles,the bioaccumulation characteristics of enrofloxacin and ciprofloxacin in C.vulgaris,D.magna,and Q.spinosa tadpoles were studied.The enrichment abilities of D.magna and Q.spinosa tadpoles to these two quinolone antibiotics through direct exposure groups and feeding groups on phytoplankton were compared.the related characteristics of bioaccumulation,tissue distribution and food chain transmission behavior of enrofloxacin and ciprofloxacin in the food chain were evaluated.The effects of enrofloxacin and ciprofloxacin on antioxidant enzymes were measured,and liver and muscle histology of Q.spinosa tadpoles were also studied.The results showed that:(1)The acute toxicity of enrofloxacin to the three green algae,D.magna and tadpoles was stronger than that of ciprofloxacin,enrofloxacin was the strongest to D.magna,and ciprofloxacin was the strongest to C.vulgaris.(2)C.vulgaris,D.magna and Q.spinosa tadpoles all have enrichment ability to enrofloxacin and ciprofloxacin,and their enrichment ability is different.Tadpoles are stronger than D.magna,D.magna are stronger than C.vulgaris.D.magna and tadpoles have stronger ability to accumulate two kinds of antibiotics directly from water than to two antibiotics through feeding.(3)Both antibiotics can be transmitted through the food chain.D.magna has a biomagnifying effect on enrofloxacin,but no biomagnification on ciprofloxacin,and tadpoles have magnifying effect on enrofloxacin and ciprofloxacin.(4)The two antibiotics accumulated mainly in the internal organs of tadpoles,which could cause histopathological changes in tadpole liver and muscle and damage the antioxidant enzyme system of tadpole liver,especially in the feeding group.