PCDD/F IN AN AGRICULTURAL FOOD-CHAIN .1. PCDD/F MASS BALANCE OF A LACTATING COW

A mass balance was conducted of the PCDD/F fluxes into and out of a lactating cow in an unmodified environment. Feed was found to be responsible for virtually all of the cow's PCDD/F exposure. Approximately 20% of the 2,3,7,8-Cl4DD toxic equivalents taken up by the cow was excreted in the milk. The measured transfer rates for a cow in a natural state generally agreed well with the results from feeding experiments in the literature. The digestive tract resorption of PCDD/F decreased with increasing degree of chlorination. Both the feces and the milk were important routes for the excretion of persistent PCDD/F isomers. © 1990.