The fate and potential effect of active pharmaceutical ingredients（APIs） as emerging chemicals on the ecological environment have been paid high attention to.In this study the acute toxicity to Photobacterium phosphoreum of 3 pharmaceuticals including aspirin

ciprofloxacin hydrochloride and azithromycin were determined by the bioassay method.Their EC50 values（10-5 mol·L-1） were 5.77

16.4 and 14.4

respectively.Based on relating models

the predicted environmental concentration（PEC） and the predicted no-effect concentration（PNEC） of 3 medicals in the effluent from sewage treatment plants in Dalian Development Zone were obtained.Risk characterization parameters（PEC/PNEC） can be regarded as comprehensive assessment factors and their estimated value ranges were 0.032-0.044

0.004-0.006 and 0.002-0.003

respectively.It was concluded that the present residual levels of 3 pharmaceuticals could be acceptable though aspirin showed highest risk among them.