Contamination of soil and groundwater at a former industrial site in Trondheim, Norway

This paper describes an investigation carried out in 1990 by the Geological Survey of Norway into the contamination of soils and groundwater at a former industrial site. The site covers an area of 0.5 ha and was used for a small plant generating gas for lighting purposes and from the middle of the last century for a small electrochemical facility (The Nidelven Brass and Iron Co. Est. 1843). The site is located immediately adjacent to the Nidelva river, in the central area of the city of Trondheim (pop. 150,000), Norway. Soil samples were obtained from 10 boreholes drilled to approximately 4 m depth. Analysis of the heavy metal content of these soil samples was subsequently undertaken. A subset of the samples was analysed for tar, including polycyclic aromatic hydrocarbons (PAH). The concentrations of Cd, Co, Cr, Hg, Ni and PAH in the soils are all below the maximum permissible levels recommended by the authorities. In certain localities, however, the concentrations of Cu, Pb and Zn are higher than the action levels at which remediation is required. It is estimated that approximately 4400 m3 of soil are contaminated, but that the contaminants are bound so tightly to the soil that the risk of dispersion of the pollutants is negligible.