title: Dioxin health risk to infants using simulated tissue concentrations.
abstract: Dioxin concentrations in infant and child were simulated using physiologically based pharmacokinetic (PBPK) models developed for these groups. The infant model was validated by comparing the simulated concentration with the measured concentration from the literature, and they showed good agreement. Simulations with our PBPK model showed temporal patterns in concentrations in various tissues. For risk assessment, estimated concentrations of 29 dioxins in the liver were summed up in a toxic equivalency (TEQ) basis to be compared with actual 2,3,7,8-TCDD concentrations in rat liver associated with toxicity. Maximum liver concentrations in breast-fed and formula-fed infants were 16.8pg TEQ/g and 3.5pg TEQ/g, respectively. The level in breast-fed infant liver was approximately 1/300 of the level associated with hepatocellular carcinoma and 1/5 of the level found in maternal rat liver associated with alterations in reproductive organs in the next generation. Based on our analysis, the present contamination level is not safe enough, but further dose-response data is required for a quantitative risk assessment.
authors.affiliation: Research Center for Environmental Risk, National Institute for Environmental Studies,16-2 Onogawa, Tsukuba 305-8506, Japan.
authors.forename: Wakae
authors.initials: W
authors.lastname: Maruyama
authors.forename: Kikuo
authors.initials: K
authors.lastname: Yoshida
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Aoki