The accumulation of persistent organic pollutants by three passive sampling media--semipermeable membrane devices (SPMDs), polyurethane foam (PUF) disks, and an organic-rich soil--was investigated. The media were exposed to contaminated indoor air over a period of 450 days, and concentrations in the air and in the media were monitored for individual polychlorinated biphenyl (PCB) congeners and polychlorinated naphthalene homologue groups. Uptake was initially linear and governed by the surface area of the sampler and the boundary layer airside mass transfer coefficient (MTC). Mean values of the MTC were 0.13, 0.11, and 0.26 cm s-1 for SPMD, PUF, and soil, respectively. As the study progressed, equilibrium was established between ambient air and the passive sampling media for the lower molecular weight PCB congeners. This information was used to calculate passive sampler-air partition coefficients, KPSM-A. These were correlated to the octanol-air partition coefficient, and the resulting regressions were used to predict KPSM-A for the full suite of PCBs. Information on MTC, KPSM-A, surface area, and effective thickness of each sampler was used to estimate times to equilibrium for each medium. These ranged from tens of days for the lower molecular weight congeners to tens of years for the higher molecular weight PCBs. Expressions were also developed to relate the amount of chemical accumulated by the passive sampling media to average ambient air concentrations over the integration period of the sample.

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Atmospheric concentrations and particle/gas partition coefficients were measured for PAHs, PCBs, and PCNs in urban Chicago during February/March 1995. Average (n = 15) concentrations (pg m-3) were ΣPAH = 58 000, ΣPCB = 350, and ΣPCN = 68. The partitioning of these compounds between the particle phase and the gas phase was investigated and compared to the adsorption (Junge−Pankow) model, which utilizes the subcooled liquid vapor pressure as a fitting parameter, and the K OA absorption model. The K OA model was able to resolve differences between ortho-chlorine substituted groups of PCBs which correlations against were not able to explain. Partitioning of PCNs was also well described by the K OA model. For PAHs, sorption onto particles agreed with both models when the wind was predominantly from the SW sector. When air was sampled from the NE sector, PAHs showed enrichments in the particle phase relative to the chlorinated aromatics in log−log plots of the particle/gas partition coefficient, K P versus Enrich ment factors calculated as K P (PAH)/K P (multi - ortho PCB) were 27−100 from the NE sector compared to 2−4 for the SW sector. This suggests source region effects on K P for PAHs. It is hypothesized that the enrichment may be due to nonexchangeable PAHs trapped inside combustion aerosols or a result of a slow re-equilibration of these aerosols as they are diluted in ambient air.

Polybrominated diphenyl ether (PBDE) body burdens in North America are 20 times that of Europeans and some "high accumulation" individuals have burdens up to 1-2 orders of magnitude higher than median values, the reasons for which are not known. We estimated emissions and fate of sigma PBDEs (minus BDE-209) in a 470 km2 area of Toronto, Canada, using the Multi-media Urban Model (MUM-Fate). Using a combination of measured and modeled concentrations for indoor and outdoor air, soil, and dust plus measured concentrations in food, we estimated exposure to sigma PBDEs via soil, dust, and dietary ingestion and indoor and outdoor inhalation pathways. Fate calculations indicate that 57-85% of PBDE emissions to the outdoor environment originate from within Toronto and that the dominant removal process is advection by air to downwind locations. Inadvertent ingestion of house dust is the largest contributor to exposure of toddlers through to adults and is thus the main exposure pathway for all life stages other than the infant, including the nursing mother, who transfers PBDEs to her infant via human milk. The next major exposure pathway is dietary ingestion of animal and dairy products. Infant consumption of human milk is the largest contributor to lifetime exposure. Inadvertent ingestion of dust is the main exposure pathway for a scenario of occupational exposure in a computer recycling facility and a fish eater. Ingestion of dust can lead to almost 100-fold higher exposure than "average" for a toddler with a high dust intake rate living in a home in which PBDE concentrations are elevated.

This study presents concurrently sampled ambient air data for a range of persistent organic pollutants at the continental scale. This was achieved using a passive air sampling system, deploying polyurethane foam disks, which was prepared in one laboratory, sealed to prevent contamination, sent out by courier to volunteers participating in different countries, exposed for 6 weeks, collected, resealed, and returned to the laboratory for analysis. Europe was the study area--a region with a history of extensive POPs usage and emission and with marked national differences in population density, the degree of urbanization and industrial/agricultural development. Samplers were deployed at remote/rural/urban locations in 22 countries and analyzed for PCBs, a range of organochlorine pesticides (HCB, alpha-HCH, gamma-HCH, ppDDT, ppDDE), and PBDEs. Calculated air concentrations were in line with those obtained by conventional active air sampling techniques. The geographical pattern of all compounds reflected suspected regional emission patterns and highlighted localized hotspots. PCB and PBDE levels varied by over 2 orders of magnitude; the highest values were detected in areas of high usage and were linked to urbanized areas. HCB was relatively uniformly distributed, reflecting its persistence and high degree of mixing in air. Higher gamma-HCH, ppDDT, and ppDDE levels generally occurred in South and East Europe.

The Global Atmospheric Passive Sampling (GAPS) study aims to demonstrate the feasibility of using passive samplers to assess the spatial distribution of persistent organic pollutants on a worldwide basis. The GAPS network includes more than 40 sites on 7 continents, mainly in background locations, with some representation of urban and agricultural areas. Here we present concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in polyurethane foam disk samplers, deployed from December 2004 to March 2005. Legacy OCPs such as alpha-HCH (hexachlorocyclohexane), Chlordanes (trans- and cis-Chlordane and trans-Nonachlor), Dieldrin, and dichlorodiphenyltrichloroethane isomers were detected at most sites with some high values that may be related to possible continued use and/or re-emissions related to historic use. Geometric mean (GM) air concentrations (pg/m3) were: 8.5 for sigmaHCH (sum of alpha- and gamma-isomers), 2.6 for sigmaChlordanes, 0.8 for Dieldrin, and 0.8 for p,p'-DDE. Current-use pesticides such as gamma-HCH (lindane) and especially Endosulfan I exhibited more variable and higher concentrations with GMs of 5 and 58, respectively. PCBs and PBDEs were elevated at urban/suburban sites consistent with their historical use pattern. GM concentrations (pg/m3) were 17 for PCBs and 4 for PBDEs. Sampling under GAPS will continue and will eventually allow seasonality effects and longer-term temporal and spatial trends to be evaluated.

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