Migration of PCBs from sealants to adjacent material

PCB in sealants can migrate into porous surfaces like concrete and brick and contaminate these materials. The study focuses on an analysis of concentration profiles in relation to alleviation of PCB contamination. The PCB content was determined in 20 samples of concrete and 6 samples of brick adjacent to outdoor PCB-containing sealants. The samples were submitted to the laboratory for normal commercial assessment of PCB content in relation to the handling of waste from renovation works in Denmark. The results showed that the PBC concentration in the sealant not necessarily relate to the concentration of the adjacent material. The profiles of PCB concentration into the materials showed some variation, though in general there is a tendency of relative higher concentration near the primary source in concrete and longer migration at low concentrations in brick. The concentration profiles seemed to fit an exponential function for concrete and a power function for brick. Based on the sample series, a worst case scenario for migration was defined. For concrete, it showed that a concentration of less than 50 ppm in the material (hazardous waste) was reached at a distance of 5 cm, whereas for bricks the distance was 3.5 cm.