Status of the PCDD and PCDF contamination of commercial milk caused by milk cartons

Within the scope of this study, possible migration of polychlorinated dibenzodioxins and -furans (PCDDs/PCDFs) from cartons (produced using bleached cardboard) into cow's milk was investigated. Three different types of carton were examined. The milk samples were taken at different times of storage and analysed for PCDDs/PCDFs. In contrast to a similar study carried out in 1990, the I-TEQ-results of all cartons analysed may be considered very low. No significant migration of toxic (2,3,7,8-chlorine-substituted) PCDDs/PCDFs could be observed. This is due to the very low PCDD/PCDF concentrations in modern cardboards as a result of the elemental chlorine-free (ECF) bleaching processes used. As far as the milk samples are concerned, no influence of the cardboards (according to the I-TEQ data) could be ascertained. I-TEQ concentrations in milk did not noticeably change during storage times of three, six and eight days. The I-TEQ-data obtained for all milk samples was found to be in the range typical of background concentrations in cow's milk in Germany. Although 1,2,7,8-TCDF is not included in the calculation of the TEQ (no 2,3,7,8-chlorine-substitution), analysis of this congener in cardboard samples was also carried out as a matter of general interest for cardboard investigations and an indicator of pulp bleaching with free chlorine.