Emissions of Tetrachlorobiphenyls (PCBs 47 51 and 68) from Polymer Resin on Kitchen Cabinets as a Non-Aroclor Source to Residential Air

摘要

We found both Aroclor and non-Aroclor sources of airborne polychlorinated biphenyls (PCBs) in residential homes. We deployed passive air samplers at sixteen residences and found PCB-47, PCB-51, and PCB-68 to account for up to 50% of measured indoor ΣPCBs (2700 pg m⁻³). Although PCB-47 and PCB-51 are neurotoxins present in Aroclor mixtures (<2.5 and <0.3 wt%, respectively), we found them at much higher levels than expected for any Aroclor source. PCB-68 is not present in Aroclor mixtures. Another non-Aroclor congener, PCB-11, a byproduct of pigment manufacturing, was found inside and outside of every household and was frequently the predominate congener. We conducted direct measurements of surface emissions and identify finished cabinetry to be a major source of PCB-47, PCB-51 and PCB-68. We hypothesize that these congeners are inadvertent byproducts of polymer sealant manufacturing and produced from the decomposition of 2,4-dichlorobenzoyl peroxide used as an initiator in free-radical polymerization of polyester resins. The presence of these three compounds in polymer products, such as silicone, has been widely noted, but to our knowledge it has never been shown to be a significant environment source of PCBs.