Environ. Sci. Technol. 2005, 39, 261-267
Field Calibration of Rapidly Equilibrating Thin-Film Passive Air Samplers and Their Potential Application for Low-Volume Air Sampling Studies N. J. FARRAR,† T. J. HARNER,‡ A . J . S W E E T M A N , † A N D K . C . J O N E S * ,† Environmental Science Department, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster LA1 4YQ, U.K., and Meteorological Service of Canada, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada
This paper reports on a field calibration and ambient deployment study with rapidly equilibrating thin-film passive air samplers. POlymer-coated Glass (POG) samplers have a coating of ethylene vinyl acetate (EVA) less than 1 µm thick coated on to glass, which can be dissolved off after exposure and prepared for quantification of persistent organic pollutants (POPs) that have partitioned into the film during field exposure. In this study, POGs were exposed for up to18 d, in a study to assess compound uptake rates and their time to approach equilibrium. Results confirmed theoretical predictions, with time to equilibrium varying between a few hours to ca. 20 d for PCB-18 and PCB-138, respectively. Performance reference compounds and contaminated POGs were used to investigate depuration kinetics, confirming that lighter congeners behave extremely dynamically with substantial losses from the films over periods of a few hours. Repeated deployments of the samplers for different 3-d periods yielded detectable levels of a range of PCB congeners, which had partitioned from as little as ∼2 to 10 m3 air. This highlights the potential utility of POGs for extremely sensitive and dynamic passive air sampling in the future to help improve understanding of sources, environmental fate, and behavior of POPs. Recommendations are made for future improvements/refinements in POG sampling and handling procedures.
Introduction There is considerable interest at present in developing and utilizing passive air samplers (PAS) for persistent organic pollutants (POPs) in the ambient environment (1-6). PAS provide exciting opportunities to cheaply and efficiently identify sources of POPs and to better understand their environmental distribution, fate, and behavior (7-9). Most of the attention to date has focused on samplers that “integrate” POPs from the atmosphere over time frames of weeks, months, or years. This limits the interpretation of data and excludes processes that affect air concentrations over relatively short time periods (e.g., hours to days). * Corresponding author phone: +44-1524-593972; fax: +44-1524593985; e-mail:
[email protected]. † Lancaster University. ‡ Environment Canada. 10.1021/es048904y CCC: $30.25 Published on Web 11/25/2004
2005 American Chemical Society
However, a rapidly responding “dynamic sampler”, with a low capacity to store POPs has been developed recently, whichsonce calibrated and better understoodscould facilitate more processed-based studies including source characterization and the determination of gradients/source strengths. This sampler consists of a thin (e.g.,
