Assessing the risks from 2,3,7,8 TCDD and TCDF in milk packaged in paper

PCDD and PCDF measurements were made on selected retail milk products, including paper packaged milk samples, covering all known paper carton suppliers in the state of California during 1989. Significant levels of 2,3,7,8 tetrachlorodibenzofuran (TCDF) and 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) were found in the paper packaged milk in all brands investigated except one. All other 2,3,7,8 substituted PCDFs and PCDDs were either not detected or detected at very low levels. Two non 2,3,7,8 substituted TCDFs were consistently detected in the contaminated milk samples. Using the mean concentration of 2,3,7,8 TCDF and TCDD detected and assuming a 480 ml daily consumption of milk for an adult, we estimated that the milk represented an additional 2.3 pg/kg/day of TCDD equivalent exposure based on the California toxic equivalence (CA TE), but only a 0.56 pg/kg/day increase using the International TE (ITE). The lifetime cancer risk was calculated to be 470 10 6 (CA TE) and 80 10 6 (ITE). Monitoring of retail milk products continued during 1990 but 2,3,7,8 TCDD and 2,3,7,8 TCDF were either not detected or detected at very low levels in all products investigated.