Embryotoxicity of zinc pyrithione, an antidandruff chemical, in fish

Early-life-stage toxicity tests of zinc pyrithione (Zpt) and commercial sha mpoos containing or not containing Zpt were performed on zebra fish and Jap anese Medaka. The results showed that Zpt induced significant teratogenic e ffects on larvae of both species of fish. The two antidandruff shampoos con taining Zpt induced the same teratogenic effects as Zpt, The calculated EC5 0 concentrations of Zpt for each of the shampoos were consistent with the E C50 for Zpt concentrate. Furthermore, 23 other shampoos not containing Zpt showed no teratogenic effects, These results strongly suggest that Zpt is t he main factor in the antidandruff shampoos. (C) 1999 Academic Press.