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(P192) Potential for Photodegradation of Contaminants During SPMD Sampling.
Orazio, Carl*,1, Haynes, Sekeenia1,2, Lebo, Jon, Meadows, John, Huckins, James, Petty, Jimmie, 1 USGS, Columbia Environmental Research Center, Columbia, MO, USA2 Florida A&M University, Environmental Sciences Institute, Tallahassee, FL, USA
ABSTRACT- Accurate assessment of polycyclic aromatic hydrocarbons (PAHs) in the environment can be compromised if they are degraded during the sampling and analysis process. The potential for photodegradation of PAHs during SPMD water and air sampling was evaluated. A commercially available SPMD canister, with perforated walls, was used to house PAH-spiked SPMDs, which were then deployed for 2 weeks under Midwest USA summertime conditions. (Control PAH-spiked SPMDs were kept in the dark). After exposure, the SPMDs were dialyzed and analyzed by HPLC/UV. SPMDs submerged 1 meter deep in moderately clear pond water showed no PAH degradation. However, under typical air-sampling conditions, a number of the PAHs within the SPMD were significantly degraded, especially those of well-known photosensitivity. Simulation of the SPMD retrieval process (in which a the SPMD is unloaded from the canister- exposing it briefly to direct sunlight, and then transferred to an airtight container) resulted in severe PAH photodegradation. Quality control measures were developed to monitor exposure of SPMDs to detrimental levels of sunlight. These measures include placing an appropriate photosensitive PAH in the triolein of the SPMD prior to deployment. Such an approach can be used as a quality assurance measure for SPMD sampling of other photosensitive compounds such as polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzodioxins/furans (PCDDs/PCDFs).
Key words: SPMD, photodegradation, PAH, PBDE
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