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Laboratory study of the PCB transport from primary sources to building materials
Liu, X., Z. Guo, Ken Krebs, D. Greenwell, N. Roache, A. Stinson, J. Nardin, AND R. Pope. Laboratory study of the PCB transport from primary sources to building materials. Indoor and Built Environment. SAGE Publications, THOUSAND OAKS, CA, 25(4):635-650, (2016).
This paper summarizes the laboratory research results for PCB transport from primary sources to PCB sinks, including PCBs from air to interior surface materials. In this study, we identified potentially useful mathematical tools for predicting the behavior of PCB sinks in PCB-contaminated buildings and estimated the key parameters such as sorption capacity, partition coefficients, and diffusion coefficients required by the tools. This study complements and supplements a field study in school buildings conducted by the U.S. Environmental Protection Agency (EPA) National Exposure Research Laboratory (NERL).
The sorption of airborne polychlorinated biphenyls (PCBs) by twenty building materials and their subsequent re-emission (desorption) from concrete were investigated using two 53-L environmental chambers connected in series with a field-collected caulk in the source chamber serving as a stable source of PCBs and building materials in the test chamber. During the tests, the PCB concentrations in the outlet air of the test chamber were monitored and the building materials were removed from the test chamber at different times to determine their PCB content. Among the materials tested, a petroleum-based paint, a latex paint, and a certain type of carpet were among the strongest sinks. Solvent-free epoxy coating, certain types of flooring materials, and brick were among the weakest sinks. For a given sink material, PCB congeners with lower vapor pressures were sorbed in larger quantities. Rough estimates of the partition and diffusion coefficients were obtained by applying a sink model to the data acquired from the chamber studies. A desorption test with the concrete panels showed that re-emission is a slow process, suggesting that PCB sinks, e.g. concrete, can release PCBs into the air for a prolonged period of time (years or decades). This study could fill some of the data gaps associated with the characterization of PCB sinks in contaminated buildings.