Abstract

In this report, results are presented of a follow-up study on levels of the seventeen toxic congeners of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (together called 'dioxins') in samples of cow's milk from dairy farms in the vicinity of the municipal waste incinerators (MSWs) at Almaar and Zaandam (the Netherlands). Milk samples were collected at regular intervals over a month's period (27 September - 27 October 1989) and subsequently mixed to time-averaged samples. Levels of dioxins are expressed in picogram 2,3,7,8-TCDD- toxicity equivalents per gram of milk fat (pg TEQ/g). Time-averaged dioxin levels in the milk of five dairy farms in Alkmaar appeared to range between 5.1 and 8.1 pg TEQ/g, 12.1 pg TEQ/g. The dioxin levels in milk of two farms in Alkmaar and of three farms in Zaandam were above the maximum allowable limit of 6 pg TEQ/g. Milk samples (daily milk production) from these farms have been collected on 19 and 20 February 1990. The level in the samples from the farms in Alkmaar were below the 6 pg TEQ/g of September/October. The dioxin level in milk samples from Zaandam were all above the 6 pg-limit and were on average (10.9) not significantly different from the level in time-averaged samples of September/October.