Abstract
The impact of chemical pollution has focused almost exclusively on the high production or notorious toxic chemicals. The drugs have been uninteresting products for researchers despite of their high physiologic activity. The EC50s of 27 antibiotics were determined as the screening test in order to assess the environmental risk. Two (Penicillin G benzathine and Gentamicin sulfate) of 27 antibiotics showed high toxicity (EC50 is less than 1mg/L) against Daphnia magna. The risk assessment with most toxic antibiotic (Penicillin G benzathine) did not show the concerned level.
