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Laboratory evaluation of polychlorinated biphenyls encapsulation methods
Liu, X., Z. Guo, Ken Krebs, N. Roache, R. Stinson, J. Nardin, R. Pope, C. Mocka, AND R. Logan. Laboratory evaluation of polychlorinated biphenyls encapsulation methods. Indoor and Built Environment. SAGE Publications, THOUSAND OAKS, CA, 25(6):895-915, (2016).
This study answers some of these questions by using a combination of laboratory testing and mathematical modeling. The results should be useful to mitigation engineers, building owners and managers, decision-makers, researchers, and the general public.
Effectiveness and limitations of the encapsulation method for reducing polychlorinated biphenyls (PCBs) concentrations in indoor air and contaminated surface have been evaluated in the laboratory study. Ten coating materials such as epoxy and polyurethane coatings, latex paint, and petroleum-based paint were tested in small environmental chambers to rank the encapsulants by their resistance to PCB sorption and estimate the key parameters required by a barrier model. Wipe samples were collected from PCB contaminated surface encapsulated with the coating materials to rank the encapsulants by their resistance to PCB migration from the source. A barrier model was used to calculate the PCB concentrations in the sources and the encapsulant layers, and at the exposed surfaces of the encapsulant and in the room air at different times. The performance of the encapsulants was ranked by those concentrations and PCB percent reductions. Overall, the three epoxy coatings performed better than the other coatings. Both the experimental results and the mathematical modeling showed that selecting proper encapsulants can effectively reduce the PCB concentrations at the exposed surfaces. The encapsulation method is most effective for contaminated surfaces that contain low levels of PCBs.