Abstract

In this paper, results are reported of a monitoring study on levels of PCDDs and PCDFs in cow's milk from dairy farms in the vicinity of two municipal solid waste incinerators (MSWs) and a metal recelamation plant in the Netherlands. Levels are expressed in picograms 2,3,7,8- TCDD toxicity equivalents (TEQ) per gram of milk fat, calculated on the basis of international toxicity equivalence factors (I-TEF) of individual components. Samples consisted of time-averaged sampling of cow's milk during periods of one month of in total eight dairy farms in Duiven, in the Lickebaert-area and in Culemborg. Samples were collected in the period from January to April 1991. The following conclusions have been drawn. 1. In the area near the MSW at Duiven, dioxin levels were between 2.2+-0.1 and 5.9+-0.3 and remained below the Dutch legislation level for dioxins in cow's milk (6 pg TEQ/g fat). Mean dioxin level in cow's milk of the two dairy farms in Duiven during this period (3.3pg TEQ/g of milk fat) were lower than the mean of the previous period (3.9pg TEQ/g of fat). 2.2 In the vicinity of the metal reclamation plant in Culemborg, levels ranged between 5.9 +- 03 and 2.8 +- 0.1 pg TEQ/g of fat. The dioxin level in this area also remains below the Dutch legislation level for dioxins in cow's milk. The mean dioxin level (4.4 pg TEQ/g of milk fat) in cow's milk of this dairy farm was comparable with the mean level of the previous period (4.3 pg TEQ/g of fat). 3. Levels of dioxins in cow's milk in the Lickebaert area were between 4.4 +- 0.2 and 11.0 +- 0.6 pg TEQ/g of fat. The mean level of five dairy farms (5.9 pg TEQ/g of milk fat) during the period January-April 1991 was lower than the corresponding mean in the previous period (7.9 pg TEQ/g of fat). It is not clear whether this decline is incidental or structural.