PCB contamination in indoor buildings

摘要

PCBs can still be found in open applications such as additives in paints or elastic sealants used in buildings built in the 1960s and 1970s. The objectives of this study were to analyze the occurrence of PCBs in paints used in buildings. PCBs were applied especially in chlorinated rubber paints, cyclorubber paints and in vinyl paints, which have been used widely, especially in industrial buildings. The results from the research show that 60% of buildings studied contain PCB over 20 mg/kg in indoor paints. From all the samples collected almost every fourth contained PCBs over the limit value of 50 mg/kg given for hazardous waste. The highest concentration (102 900 mg/kg) was found in the concrete floor of a school building's basement. Wipe samples taken from paint surfaces also contained high amounts of PCBs. The highest amount (83 000 μg PCB/m~2) was found in the surface of a building, which had not yet been renovated. The most common method for removing existing paint is sandblasting. After sandblasting the sand contains high concentrations of PCBs and has a large surface area thus PCBs leaching capacity may be significant. This may cause occupational and also residential exposure to PCBs. In buildings that had been renovated by using sandblasting for paint removal, PCBs were found in the surface, which had not originally contained PCBs. The secondary contamination was often over the Finnish limit value of 100 μg PCB/m~2 as the highest concentration detected was 1100 μg PCB/m~2. The congener profiles from the samples reminded the profile of Aroclor 1260 or Clophen 60 profiles in almost all samples. The profiles showed that the PCBs most probably originate from paints and not from other PCB source such as capacitors.