Abstract
Xenopus laevis embryos at blastula stage were exposed to 0.1ppt-100ppb 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) for 72 h, and then they were mainteined in TCDD-free dechlorinated water till 50 days after fertilization. Effects of TCDD could not be found at the concentration of 10 ppb and below. However, 6 of 13. larvae exposed to 100 ppb TCDD developed edemas in the head, breast and abdomen at 10-18 days after fertilization. Four of them died within a few days, and the remainder recovered from the edemas. The incidence of edemas and death in the 100 ppb group was significantly higher than controls.
