[Political poisoning with dioxins--a weapon of chemical "disgracefulness"]

The recent attempt to poison Ukrainian President, Viktor Yuschenko with dioxins, raised public concern regarding this toxic chemical. In industrial countries, there is a constitutive exposure of humans to dioxin compounds, which are formed as by-products in manufacturing processes of various chlorinated organic chemicals and in waste incinerators. Dioxins are extremely stable in the environment and have a low turnover rate in the body--sometimes they are detected years after the original exposure. Of the dioxins, the most notoriously famous is the TCDD (2,3,7,8 tetrachlorodibenzo-p-dioxin). Dioxins exhibit high acute toxicity in various animal species. Humans, however, are considered less susceptible and so far there were no reported deaths following acute dioxin poisoning. Nevertheless, numerous adverse health effects are attributed to dioxin exposure. The most prominent is the chloracne--an acute acneiform eruption, usually appearing on facial skin. There is a solid evidence base that some dioxins are carcinogens. Other long-term deleterious effects of dioxin include: immunosuppression, effects on reproduction, impairments in developmental, neurological and cognitive functions in infants, increased risk for diabetes and cardiovascular diseases and various hormonal alterations. The action of dioxins resembles that of hormones, since their toxicity is mostly receptor-mediated. Dioxins manifest their toxicity in extremely low concentrations. Although there are compounds that exhibit their biological activity at even lower dose range (e.g. nerve gases), this potency of dioxins is considered extraordinary, since there is an every-day exposure to dioxins through environmental vectors mostly via the food chain. Until now, there is no antidotal cure for dioxins, but only symptomatic treatment combined with techniques that accelerate its excretion rate from the body.