Järnsjön, a lake in the Swedish river Emån, contains approx. 400 kg of PCB which is slowly leaching out from the sediments. An analysis program has shown that the Järnsjön sediments are the primary source for ongoing discharge of PCB to the river. Based on the current yearly discharge of 7 kg PCB, the sediments will cause problems during several decades.
The Emän river is classified as a resource of national importance. Remediation of Järnsjön is necessary if continued damage is to be avoided. However, remedial activities in lake Järnsjön can lead to an additional load on Emån. Restrictions on such releases during remediation of Järnsjön will therefore be stringently applied.
The feasibility of remediating Järnsjön, has been examined in a number of studies carried out by the Swedish EPA together with different universities, institutes and consulting companies. A primary alternative has been selected. This alternative includes vacuum dredging within a protective barrier of silt screens. Dredged material will be dewatered and disposed of in a special landfill. This remedial action is estimated to cost appr. 40 million Swedish kronor. (6 - 8 million dollars). The remediation has started and will be concluded in 1994.