Investigation of the importance of tertiary contamination, temperature and human behaviour on PCB concentrations in indoor air

Abstract

High concentrations of polychlorinated biphenyls (PCBs) can still be measured in indoor air in many buildings built or renovated within the period from approximately 1950 until the late seventies. The increasing evidence of the importance of indoor exposure to PCBs has led to the initiation of remediation actions in many countries. Understandably, primary sources with original PCB content have been the main focus of the actions. However, removal of primary sources alone has shown to be insufficient in decreasing the high indoor PCB concentrations in contaminated buildings. The aim of this study was to investigate the importance of tertiary PCB sources to indoor air concentrations and identify predictors of PCB air concentrations in contaminated buildings. In this study, 24 PCB congeners were measured in the indoor air of 83 contaminated apartments as well as in sealants sampled in a random subset of 20 apartments. The sealants were identified to be the primary source containing the original PCBs. For total PCBs, the median air concentration was 859 ng/m3 and the median concentration in contaminated sealants was 16.5% by weight. Analyses performed in the present study indicate that the influence of tertiary sources on indoor air concentrations may be substantial and that removal of tertiary sources may be needed when performing PCB remediation in buildings.