Inventering och riskklassning av förorenade områden i Öna och Östnor

Abstract: This work consists of a survey and risk classification of eleven metal industries including foundries, finishers and engineering industries in two industrial areas in Mora. The study follows a method called MIFO (Method of Surveying Contaminated Sites) composed by the Swedish Environmental Protection Agency. In the method assessments of the degree of hazard posed by the pollutants, the level of pollution, the conditions of dispersal, sensitivity and the degree to which the area is worthy to protect are made for each contaminated site (object). The assessment classify the objects into four risk classes in which risk class 1 denotes a very large risk, 2 large risk, 3 moderate risk and risk class 4 little risk. The work of surveying using MIFO is divided into two phases. In the first phase, an over-view of the situation is achieved by studying maps, archives and making visits and interviews. In the second phase, an in-depth study is being done involving sampling of soil water and ground water. The surveying made in this work is mainly a phase 1 study and the investigations were made with help from the County Administrate Board of Dalarna. The two industrial areas that have been studied are named Öna and Östnor and have been industrialised for a very long time. The consequence of the long-term industrial history is that the industrial places are closely embedded in an urban area. Due to the fact that people are living nearby the industries the areas were classified as sensitive to contaminants. No soil sampling was done in the area but as a consequence of the high density and long duration of industrial activities metals, cyanide, trichloroethene, oil and solvents are likely pollutants. Most of the industries have earlier used the nearby streams as recipients without any treatment of the polluted waste water. A couple of samples have previously been taken in the stream sediments, which showed a high content of for example copper, zinc, chromium and nickel. Nine of the eleven objects in this study where assigned to be in the risk class 2 (large risk) and two in risk class 3 (moderate risk). Because of the fact that possible surveys will be made in phase two of MIFO, the risk assessments are based mostly on a "worst case scenario". Within a phase-two study a better picture of the 'actual scenario' would be given. If remediation of some of these areas are needed in the future, different remediation methods would be possible, for example soil washing, phytoremediation or inclosing (if the pollutants are present below buildings). For remediation of sediments dredging followed by burning of the dredge masses can be of interest.