Toxic interaction of 2,3,7,8-TCDD, 2,3,7,8-TCDF,1,2,3,7,8-PeCDD, and 1,2,3,4,7,8-HeCDD: On the Japanese medaka (Oryzias latipes)

The Japanese medaka (Oryzias latipes) early-life-stage (ELS) and 7-ethoxyresorufin O-deethylation (EROD) assays were used to test the hypothesis of additivity for toxic and biochemical effects from binary mixtures of chlorinated dioxins and furans. The effect of the appearance of any lesion in developing embryos was additive for the mixture of TODD with 1,2,3,7,8-PeCDD, 1,2,3,4,7,8-HeCDD or 2,3,7,8-TCDF. The induction of EROD activity decreased statistically in the TCDF/PeCDD and the TCDD/HeCDD combinations. For other combinations, the effects were simply additive. The uptake of [3H]-TCDD by either embryos or larvae was not affected by the presence of another congener at the concentrations studied.