Although all countries could be affected, most contamination cases have been reported in industrialized countries where adequate food contamination monitoring, greater awareness of the hazard and better regulatory controls are available for the detection of dioxin problems. Short-term exposure of human to high levels of dioxins may result in skin lesions, such as chloracne and patchy darkening of the skin, and altered liver function. Long-term exposure is linked to impairment of the immune system, the developing nervous system, the endocrine system and reproductive functions. Chronic exposure of animals to dioxins has resulted in several types of cancer. However, TCDD does not affect genetic material and there is a level of exposure below which cancer risk would be negligible.
Foetuses are most sensitive to dioxin exposure.
Newborns may also be more vulnerable to certain effects. Risk must be calculated on a case by case basis taking into account the levels of exposure and population sub-groups affected. Accurate information about the level of dioxin in the food, the amount of contaminated food consumed, and the duration of exposure to dioxin is needed to assess the actual risk of exposure. With this information at hand, an assessment of the health impact can be performed and used as a basis for policy decisions. The TDI is calculated on the basis of exposure over a lifetime and the accumulated amount of dioxins in the body.