Developmental evaluation of a potential non-steroidal estrogen: triclosan

Triclosan is an antibacterial agent commonly used in industry and often det ected in wastewater effluent. The potential of triclosan to act as an endoc rine disrupter was examined because its chemical structure closely resemble s known non-steroidal estrogens (e.g. DES, bisphenol A). Japanese medaka fr y (Oryzias latipes) were exposed for 14 days beginning 2 days post-hatch to triclosan (100, 10, 1 mug/l), 17-beta estradiol (E2; 1 mug/l), or a solven t control (ethanol). Two months post-exposure, the phenotypic sex of each a dult was assessed visually using sexually dimorphic fin shape and size. The proportion of females in each group was similar for triclosan-exposed anim als and solvent-treated controls (ethanol 53%, 1 ppb 58%, 10 ppb 45%, 100 p pb 36%) although E2 treatment did produce 92% female adults. Sexually dimor phic fin traits were quantified to look for potential effects of triclosan and E2 on the development of secondary sexual Characters. These results do not support the hypothesis that triclosan is potently estrogenic. However, changes in fin length and non-significant trends in sex ratio suggest tricl osan is potentially weakly androgenic. (C) 2000 Elsevier Science Ltd. All r ights reserved.