A National Survey of Dioxin-Like Compounds in the U.S. Milk Supply
The exposure portion of the United States Environmental Protection Agency's (EPA) Dioxin Reassessment has concluded that over 90% of human exposure to dioxin (and related compounds) occurs via food ingestion, primarily meats, dairy products, and fish. Therefore, EPA has undertaken a program to monitor the national food supply for dioxin-like compounds. Surveys have now been completed for beef, pork, and poultry. This paper reports on a national survey for dioxins in milk. The purpose of this survey was to assess the national prevalence and concentrations of polychlorinated dibenzo-p-dioxins (CDDs), polychlorinated dibenzofurans (CDFs), and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) in the general pasteurized milk supply of the United States. This survey, conducted in 1998, was not designed to be statistically rigorous. That is, it was not the intention to randomly sample a defined population of milk such that the results could be extrapolated back to the nation's total milk supply with a known degree of precision. This milk survey had three primary objectives: 1) to provide a non-statistical estimate of the average concentrations of the dioxin-like compounds in pasteurized milk in the United States milk supply; 2) to assess geographic variability of dioxins in this milk supply; and 3) to assess temporal variability of dioxins in this milk supply.