Abstract

Dioxin levels in soil in the vicinity of the minicipal solid waste incinerator OLAF in Leeuwarden have been examined. Measurements were made at ten locations situated at regular intervals over a distance of 8 km north-east of the incinerator. Levels in soil were between 3+-0,5 and 23+-1 ng TEQ per kg dry matter. These concentrations are somewhat higher than the background level of ca. 10 ng TEQ per kg dry matter. Also, the proposed limit value for soil in pasture districts of 10 ng TEQ per kg dry matter is slightly exceeded. Deposition has been estimated from both emission measurements and concentrations in soil. In both cases depositions agree within a factor two. It is concluded that the present emission/deposition model is capable of predicting deposition reasonably well. The uptake of dioxins via soil by children is about 1 pg TEQ per person per day for a soil concentration of 11 ng TEQ per kg dry matter. This uptake is negligible in comparison with the background exposure of 120 pg TEQ per person per day. Dioxin levels in milk were within the background level of 0.7-2.5 pg TEQ/g milk fat. After closure of the OLAF concentrations in milk decreased considerably. It is concluded that no direct danger for public health is expected and further investigation of dioxin levels in soil and milk in this area is not recommended.