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IP06 Passive Samplers for POPs
(IP045) Calibration of semipermeable membrane devices (SPMDs) for vapor phase airborne contaminants.
Cranor, W1, Alvarez, D1, Huckins, J1, Petty, J1, Robertson, G2, 1 USGS-CERC, Columbia, MO, USA2 US EPA NERL, Las Vegas, NV, USA
ABSTRACT- People spend most of their lives inside buildings where they are exposed to complex mixtures of airborne chemicals of unknown toxicity. Exposure to contaminants in indoor air is recognized as having detrimental effects, e.g., the so-called "sick building syndrome." As an integral part of an ongoing research program, scientists at the USGS's Columbia Environmental Research Center (CERC) are conducting joint research with EPA scientists to calibrate the semipermeable membrane device (SPMD) as an air sampler for monitoring atmospheric and indoor air quality. Sampling rate data has been collected to generate algorithms necessary to employ this passive integrative sampling device as a quantitative air sampler. A vapor phase chemical production and delivery system capable of generating and maintaining constant concentrations of vapor phase chemical mixtures was developed for the calibration of the SPMDs (patent pending). The system was operated for 60 days with current use pesticides, historic use organochlorine pesticides (OCPs), and polynuclear aromatic hydrocarbons (PAHs). Polyurethane foam plugs and charcoal impregnated polyurethane foam plugs were used to monitor the test chemical concentrations in the air stream. SPMDs were exposed to the mixture of chemicals for 3, 6, 9, 12, 15, 18, 24, and 30 days at an air flow rate of 4.2 L/min. Replicate SPMDs (n = 3) were collected at each point and analyzed for sequestered chemicals. Constant vapor phase concentrations of 22 of the 26 targeted chemicals were maintained for a minimum of five three-day sampling periods. SPMD sampling rate data, expressed as linear-uptake rate constants (kus, units of m3 /d×g), were obtained for these 22 test chemicals. The ku values for these test chemicals were within the range of expected values based on mass transfer theory.
Key words: calibration, spmds, airborne chemicals, semivolatile
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