Elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxine in goat milk.

2,3,7,8-Tetrachlorodibenzo-p-dioxine (TCDD) 200 ng/day, was given orally to 7 goats for 2 months, followed by an elimination period of 1 month. Then a daily dose of 400 ng TCDD was given for 1 month to the same animals. Two animals were killed and the rest of the animals were observed for several months. The excretion of TCDD in milk was studied by glass capillary gas fragmentography, where the minimal detectable concentration was below 5 ppt. After the first feeding the concentration of TCDD in milk achieved a maximum of 20.8 +/- 6.6 ppt while a similar value of 19.3 +/- 6.6 ppt was observed after the second feeding. After this period, the concentration of TCDD decreased slowly with values, after 18 weeks, of 4, 2 +/-, 3 and 6 ppt. The concentration of TCDD in the liver in the two animals killed was 1039.0 and 898.0 ppt. There were no differences in clinical observations or blood and urine analyses when experimental animals were compared with controls.