Study On Ecological Toxicity Effects Of Typical Quinolone Antibiotics In Water

In the present study, three typical quinolone anbibiotics ofloxacin (OFLX),norfloxacin (NFLX) and ciprofloxacin hydrochloride (CPFX) existed largely in surfacewater environment were selected as study objects. Cyprinus carpio is the testing organism.Toxicity effects of the three typical quinolone anbibiotics to Cyprinus carpio wereinvestigated through short-term and long-term exposure tests. A comprehensive evaluationindex was established. The ecological risk level of antibiotic was got through analyzingthe integrated biomarker response index (IBR). The results showed that:1) The three antibiotics were low-toxic to Cyprinus carpio.2) SOD activity was induced after the CPFX exposure of prometaphase period (3~9d), and inhibited in the later exposure period (12~15d). MDA contents increasedsignificantly only in the prometaphase period. The GST activity had the similar trendencywith GSH. The persistent induction was determined in the0.05and0.5mg/L exposuregroups, and a variation of increased at first and then decreased steadily was determined inthe5and50mg/L groups. There was no effect on GPT activity. GOT activities wereinduced after3d exposure, inhibited after15d.3) A certain synergistic effect of SOD activity and MDA content was investigatedafter NFLX exposure. The lipid peroxidation produced in organism with time. Moreoxidative damage was induced with higher concentrations. GST and GSH were allinduced to different degrees, the most obvious induction were detected in5mg/Lconcentration group. The GPT and GOT activities increased at first and then decreased. Inthe later exposure period (12~15d), the antioxidant defense mechanism and the livertissue cells were damaged in25and125mg/L concentration groups.4) The SOD, GPT, GOT activities were induced mostly after exposure to OFLX.Enzyme activity was inhibited by high concentration exposure group (125mg/L) afterexposure for15d. The GSH and GST activities were induced except for25and125mg/Ltreatment which increased at first and then decreased. The markedly change of MDAcontent were mainly occurred in the later exposure period (12~15d). Only the125mg/Lgroup produced the oxidative damage and poison in liver tissue.5) The IBR value of0.5,5mg/L treatment and the exposure time presented a positivecorrelation after exposure to CPFX. The IBR was in the higher levels of4.315for0.5 mg/L exposure group. The intermediate levels of IBR value ranging from2.318to2.421were determined in other groups. The IBR value of25,125mg/L treatment and theexposure time presented a positive correlation after exposure to NFLX. The IBR valueincreased with increasing time. The IBR value of1,5mg/L treatment increased firstlythen decreased and finally increased with increasing exposure time, and ultimately rangedfrom2.239to2.838. For exposure to OFLX, the IBR value of25mg/L group decreasedwith the exposure time. For125mg/L treatment, the IBR value was in higher levelsranging from3.986to5.737except for12d. The IBR value of1,5mg/L groups were inthe low levels ranging from1.754to2.913.