Dioxins and Health: Human Exposure Level and Epidemiologic Evidences of Health Effects

Abstract

General information is summarized, that is necessary to introduce a scientific assessment of the human health and exposure issue concerning dioxin and dioxin-like compound. Scientific literatures were reviewed to assess the background exposures to the dioxin-like compounds for normal residents. Epidemiologic studies were also reviewed to assess malignant and nonmalignant effects of dioxins. In 1997, the International Agency for Research on Cancer classified 2,3,7,8-tetrachlorodibenzo-p-dioxin (TODD) as a human carcinogen, primarily based on occupational cohort studies. The US Environmental Protection Agency made the same decision in it's Draft Dioxin Reassessment. Epidemiologic evidences point to a generalized excess of all cancers, without any pronounced excess at specific sites. Reported non-cancer effects included a range of conditions affecting most systems. Among them, chloracne, elevation in gamma glutamyl transferase(GGT), and alterations in reproductive hormones are related to TODD. Other adverse outcomes, such as lipid concentrations, diabetes, circulatory and heart diseases, immunologic disorders, neurobehavioral effects, and developmental outcomes require further study before their respective relationships to TODD can be more definitively assessed.