title: Effects of antibacterial agents, levofloxacin and clarithromycin, on aquatic organisms.
abstract: Contamination of surface waters by pharmaceutical chemicals is an emerging environmental problem. This study evaluated the toxic effects of the antibacterial agents levofloxacin (LVFX) and clarithromycin (CAM), which are widely used in Japan, on aquatic organisms. Ecotoxicity tests using a bacterium, alga and crustacean were conducted. Microtox test using a marine fluorescent bacterium showed that LVFX and CAM have no acute toxicity to the bacterium. From the results of the Daphnia immobilisation test, LVFX and CAM did not show acute toxicity to the crustacean. Meanwhile, an algal growth inhibition test revealed that LVFX and CAM have high toxicity to the microalga. The phytotoxicity of CAM was about 100-fold higher than that of LVFX from a comparison of EC50 (median effective concentration) value. From the Daphnia reproduction test, LVFX and CAM also showed chronic toxicity to the crustacean. Concentrations of LVFX and CAM in the aquatic environment were compared with PNEC (predicted no effect concentration) to evaluate the ecological risk. As a result, the ecological risk of LVFX is considered to be low, but that of CAM is higher, suggesting that CAM discharged into an aquatic environment after therapeutic use may affect organisms in the aquatic environment.
authors.affiliation: Water Environment Research Group, Public Works Research Institute, Tsukuba, Ibaraki Prefecture, Japan. m-yama44@pwri.go.jp
authors.forename: N
authors.initials: N
authors.lastname: Yamashita
authors.forename: M
authors.initials: M
authors.lastname: Yasojima
authors.forename: N
authors.initials: N
authors.lastname: Nakada
authors.forename: K
authors.initials: K
authors.lastname: Miyajima
authors.forename: K
authors.initials: K
authors.lastname: Komori
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000378:metabolism; D017291:Clarithromycin / Q000494:pharmacology*; D003445:Crustacea / Q000187:drug effects*; D003621:Daphnia / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity*; D064704:Levofloxacin; D008956:Models, Chemical; D015242:Ofloxacin / Q000494:pharmacology*; D012306:Risk; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents; D004785:Environmental Pollutants; D014874:Water Pollutants, Chemical; D064704:Levofloxacin; D015242:Ofloxacin; D017291:Clarithromycin