Embryotoxicity of zinc pyrithione, an antidandruff chemical, in fish.

Early-life-stage toxicity tests of zinc pyrithione (Zpt) and commercial shampoos containing or not containing Zpt were performed on zebra fish and Japanese Medaka. The results showed that Zpt induced significant teratogenic effects on larvae of both species of fish. The two antidandruff shampoos containing Zpt induced the same teratogenic effects as Zpt. The calculated EC50 concentrations of Zpt for each of the shampoos were consistent with the EC50 for Zpt concentrate. Furthermore, 23 other shampoos not containing Zpt showed no teratogenic effects. These results strongly suggest that Zpt is the main factor in the antidandruff shampoos. Copyright 1999 Academic Press.