About 95% of human exposure to dioxin is through the food supply. Dioxin travels through the atmosphere and eventually settles on soils, sediments, or in the water. The dioxin is then ingested by grazing animals or quickly absorbed by fish. Since dioxin is a highly stable, fat-loving compound, it is stored in animal fat and milk for extended periods of time. Dioxin's half-life ranges significantly depending on where it is stored. Dioxin is persistent for 7-12 years in humans, 10 years in soil, and several months in beef cattle. Once stored inside an animal, the dioxin can bioaccumulate up the food chain. Humans mainly ingest dioxin through the fat of meats, skin of chicken and fish, dairy products, eggs, and milk.

• 97.5% of dioxin in our food supply is contained in meat (mainly in the fat and skin) and dairy products.
• Fish dioxin levels are 100,000 times that of the surrounding environment.
• According to the World Health Organization, the tolerable daily intake (TDI) of dioxin is in the range of 1 to 4 picograms per kilogram of body weight per day.

Source: www.epa.gov/ncea/pdfs/dioxin/part1/volume3/chap-4.pdf [PDF]