||ARCADIS Geraghty and Miller, Durham, NC.; Environmental Protection Agency, Research Triangle Park, NC. Air Pollution Prevention and Control Div.; Environmental Protection Agency, Research Triangle Park, NC. National Risk Management Research Lab.
This is the second report in the series entitled Laboratory Study of Polychlorinated Biphenyl (PCB) Contamination and Mitigation in Buildings, published by EPAÃ¢â‚¬â„¢s National Risk Management Research Laboratory. This report focuses on PCB transport from primary sources to building materials and settled dust in PCB-contaminated buildings. Building materials, furniture, and other indoor environmental constituents (such as settled dust) can Ã¢â‚¬Å“pick upÃ¢â‚¬ï¿½ PCBs through exposure to contaminated air or through direct contact with primary sources of PCBs. The adsorbed PCBs can be re-emitted into the air when the primary sources are removed or severely diminished. Thus, these contaminated materials are often referred to as reversible or re-emitting sinks because both sorption and desorption are involved. In the PCB literature, however, they are often referred to as Ã¢â‚¬Å“secondary sourcesÃ¢â‚¬ï¿½. In this report, the term Ã¢â‚¬Å“PCB sinkÃ¢â‚¬ï¿½ was used although other terms, especially Ã¢â‚¬Å“secondary sourceÃ¢â‚¬ï¿½, were also cited occasionally. Many researchers and others have recognized the presence and importance of PCB sinks in PCB-contaminated buildings, but very little information is available about the related transport processes and the re-emission characteristics. Because they are numerous, mitigating the PCB sinks as secondary sources has enormous environmental and economic implications. Better understanding of PCB sinks is important to decision makers, environmental engineers, and researchers who are concerned with risk assessment and risk management for PCB contamination.