Abstract: Dynamics,e.g.distribution,accumulation and transfer,of ciprofloxacin(CPFX) in water,sediments and biota in a simulated micro-cosmic aquatic system was studied with HPLC.Results show that once CPFX was released into water body,a portion of it was assimilated by aquatic organisms and a portion deposited into the sediments.Concentration of CPFX in water,sediments and biota varied with the time.The concentration of CPFX decreased rapidly in the water,from 500.00 to 15.30 μg·L^-1 within one day,but increased in the sediment up to 385.57 μg·kg^-1.Enrichment and residue of CPFX in aquatic organisms varied with the species.Echinodorus amazonicus adsorbed CPFX rapidly,especially in its leaves,where the concentration of CPFX reached as high as 795.43 μg·kg^-1 within one day and then turned down gradually.Carassius auratus gibelio and Corbicula fluminea were found absorbing and accumulating CPFX,which could remain in their organs as residue for as long as 45 days.Significant differences existed between these organs in CPFX bioaccumulation,and higher concentration of CPFX was found in visceral tissues than in muscular tissues.Significant differences also existed between species of organisms in CPFX distribution and accumulations,showing an order of E.amazonicus>C.fluminea>C.auratus gibelio.

Key words: micro-cosmos system, ciprofloxacin, environmental fate, HPLC