Biomonitoring of dioxins and furans: Levels and trends in humans

Abstract

Dioxins and furans are ubiquitous, lipophilic, persistent organic chemicals that can be measured in many human tissues and fluids. The most frequently biomonitored human samples are blood and human milk because of the relative ease of sample collection and because these chemicals readily partition into the lipid fraction. In this chapter we will review studies of the general population from around the world that have measured and reported concentrations and toxic equivalency values for dioxin and furans in various human tissues and fluids including milk, blood, umbilical cord blood, adipose tissue, and other tissues that are less frequently analyzed. We will also briefly discuss populations in two areas with excessive dioxin exposure: Vietnam and Seveso, Italy. The majority of the available data indicate that dioxin and furan levels in humans have been declining over the years in the general population as well as in populations with excessive exposure. In addition, there appears to be an age-related difference in levels such that older individuals have higher levels than younger individuals. However, the reader should be aware that many of the available studies are not conducted in a comparable manner and most, including those that are meant to be nationally representative, have small sample sizes. Despite these limitations, biomonitoring of dioxins and furans has been an instrumental tool for establishing baseline levels in humans, discerning trends, informing policies, and assessing the efficacy of policy actions.