Abstract:The distribution, accumulation and transfer dynamics of Ciprofloxacin(CPFX) in water, sediments and biota in a simulated micro-cosmos system using different exposure techniques were studied. In addition to photodegradation, some CPFX released into water was assimilated by aquatic organisms and some was deposited in the sediments. The concentration of CPFX in water decreased rapidly, and the highest concentration is less than 15.30μg•L-1 from the three exposure techniques. CPFX was adsorbed and accumulated in the sediments and could maintain at high concentration up to 237967μg•L-1 with feed administration. There were differences in the distribution, accumulation and transfer dynamics of CPFX in different aquatic organisms: water seed Echinodorus amazonicus adsorbed CPFX mainly by its leaf instead of its roots and the highest concentration was found to be 899.83μg•L-1; carp Allogynogenetic crucian and clam Corbicula fluminea had the ability to accumulate CPFX, which could stay in the tissue of organisms for a long time. Significant differences of CPFX bioaccumulation between the viscera and the muscle were observed, and higher concentration of CPFX was found in the former tissue. The bioaccumulations of CPFX in Allogynogenetic crucian carp were shown to be different using different exposure techniques with the following order: feed administration＞mixed administration＞water administration.