PCBs appear in school air because many school buildings were built when PCBs were still intentionally added to building materials and because PCBs are also present through inadvertent production in modern pigment. This is of concern because children are especially vulnerable to the toxic effects of PCBs. Here we report indoor and outdoor air concentrations of PCBs and OH-PCBs from two rural schools and four urban schools, the latter near a PCB-contaminated waterway of Lake Michigan in the United States. Samples (n=108) were collected as in/out pairs using polyurethane foam passive air samplers (PUF-PAS) from January 2012 to November 2015. Samples were analyzed using GC/MS-MS for all 209 PCBs and 72 OH-PCBs. Concentrations inside schools were one to two orders of magnitude higher than outdoors and ranged 0.5–194 ng/m3 (PCBs) and 4–665 pg/m3 (OH-PCBs). Congener profiles were similar within each sampling location across season but different between schools and indicated the sources as Aroclors from building materials and individual PCBs associated with modern pigment. This study is the first cohort-specific analysis to show that some children’s PCB inhalation exposure may be equal to or higher than their exposure through diet.

Both Aroclor and non-Aroclor sources of airborne polychlorinated biphenyls (PCBs) were found in residential homes. We deployed passive air samplers at 16 residences and found PCB-47, PCB-51, and PCB-68 to account for up to 50% of measured indoor ΣPCBs (2700 pg m). 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 identified 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 they have never been shown to be a significant environmental source of PCBs.

Per- and polyfluoroalkyl substances (PFASs) have come under increased scrutiny due to concerns about their potential toxicity and prevalence in the environment, particularly drinking water. PFASs are difficult to remove in full-scale water treatment systems because of their physicochemical properties. Here we evaluated the effectiveness of point-of-use (POU) and point-of-entry (POE) residential drinking water filters in removing a suite of three perfluoroalkyl sulfonic acids, seven perfluoroalkyl carboxylic acids, and six per- and polyfluoroalkyl ether acids in homes in central (n = 61) and southeastern (n = 12) North Carolina. POU systems included countertop and pitcher filters, faucet-mounted filters, activated carbon block refrigerator filters, activated carbon block under-sink filters, under-sink dual-stage filters, and under-sink reverse osmosis filters. All under-sink dual-stage and reverse osmosis filters tested showed near complete removal for all PFASs evaluated. In contrast, all other filters containing activated carbon exhibited variable PFAS removal. In these filters, PFAS removal efficiency was dependent on chain length, with long-chain PFASs (∼60–70% removal) being more efficiently removed than short-chain PFASs (∼40% removal). A few whole-house activated carbon POE systems (n = 8) were also evaluated; however, results were variable, and in some cases (four of eight systems), increased PFAS levels were observed in the filtered water.

Passive air samplers equipped with polyurethane foam (PUF-PAS) are frequently used to measure persistent organic pollutants (POPs) in ambient air. Here we present and evaluate a method to determine sampling rates (R), and the effective sampling volume (V), for gas-phase chemical compounds captured by a PUF-PAS sampler deployed anywhere in the world. The method uses a mathematical model that requires only publicly available hourly meteorological data, physical-chemical properties of the target compound, and the deployment dates. The predicted R is calibrated from sampling rates determined from 5 depuration compounds (C PCB-9, C PCB-15,C PCB-32, PCB-30, and d-γ-HCH) injected in 82 samples from 24 sites deployed by the Global Atmospheric Passive Sampling (GAPS) network around the world. The dimensionless fitting parameter, gamma, was found to be constant at 0.267 when implementing the Integrated Surface Database (ISD) weather observations and 0.315 using the Modern Era Retrospective-Analysis for Research and Applications (MERRA) weather dataset. The model provided acceptable agreement between modelled and depuration determined sampling rates, with C PCB-9,C PCB-32, and d-γ-HCH having mean percent bias near zero (±6%) for both weather datasets (ISD and MERRA). The model provides inexpensive and reliable PUF-PAS gas-phase R and V when depuration compounds produce unusual or suspect results and for sites where the use of depuration compounds is impractical, such as sites experiencing low average wind speeds, very cold temperatures, or remote locations.