A time-dependent 2,3,7,8-tetrachlorodibenzo-p-dioxin body-burden model

Abstract

Estimates of the 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) body-burden acquired from an environment in which 2,3,7,8-TCDD has been introduced in a high concentration, are derived from an idealized linear reaction kinetic model. The model parameters are the 2,3,7,8-TCDD transfer factor from the environmental soil medium to the human body, the background intake, the soil concentration and the body and soil elimination half-times. Values of the transfer factor are estimated from reported human and environmental data. The model conservatively determines a time-scale over which the acquired body-burden may be significantly higher than the background dose caused by the ubiquitous presence of 2,3,7,8-TCDD in food, consumer products, etc. and allows comparison of the cumulative body-burden with published values for the minimum toxic dose and derived values of the minimum guideline dose. The linear nature of the model also provides a framework for the estimation of the 2,3,7,8-TCDD toxic equivalent (TEQ) body-burden acquired from environments in which a mixture of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are present.