Biological half‐lives of chlorinated dibenzo‐ p ‐dioxins and dibenzofurans in rainbow trout ( Salmo gairdneri )

The biological half‐lives of five dibenzo‐ p ‐dioxins and two dibenzofurans were determined in rainbow trout following a single oral exposure. Estimated half‐lives ranged from 2 d for 2,7‐dichlorodibenzo‐ p ‐dioxin to 43 d for 1,2,3,4‐tetrachlorodibenzo‐ p ‐dioxin among the dioxins, and from 12 d for octachlorodibenzofuran to 24 d for 3,6‐dichlorodibenzofuran. No consistent relationship was shown between half‐life and the degree of chlorination. Absorption efficiencies varied from 2 to greater than 30%, although most values ranged from 5 to 16%.