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REAL-TIME AND INTEGRATED MEASUREMENT OF POTENTIAL HUMAN EXPOSURE TO PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) FROM AIRCRAFT EXHAUST
Citation:
Childers, J. W., C. L. Witherspoon, L. B. Smith, AND J D. Pleil. REAL-TIME AND INTEGRATED MEASUREMENT OF POTENTIAL HUMAN EXPOSURE TO PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) FROM AIRCRAFT EXHAUST. ENVIRONMENTAL HEALTH PERSPECTIVES 108(9):853-862, (2000).
Impact/Purpose:
The objective of this task is to develop state-of-the-art methods for measuring xenobiotic compounds, to include the isolation of the analyte from the appropriate matrix (extraction), preconcentration (typically sorbent-based), and analysis via GC/MS and/or LC/MS. Once established, these methods will be applied in small scale pilot studies or demonstration projects. Particular emphasis will be placed on methods which are readily transferable to other laboratories, including those within the Human Exposure and Atmospheric Sciences Division (HEASD), the National Exposure Research Laboratory (NERL), other EPA Laboratories, Program Offices, Regions, and academic institutions.
Specific objectives of this task include the following:
1) Development of GC/MS and LC/MS methods for the measurement of key xenobiotic compounds and their metabolites (to include the pyrethroid pesticides, perfluorinated organic compounds, and the BFRs) in relevant environmental and biological matrices.
2) Development of efficient low cost methods for the extraction and clean up of these compounds collected from relevant matrices.
3) Determination of xenobiotic compound and metabolite concentrations in samples derived from laboratory and field monitoring studies to help assess exposures and evaluate associated risks.
Description:
Real-time monitors and low-volume air samplers were used to measure the potential human exposure to airborne polycyclic aromatic hydrocarbon (PAH) concentrations during various flight-related and ground-support activities of C-130H aircraft at an Air National Guard base. Three types of photoelectric aerosol sensors (PASs) were used to measure real-time concentrations of particle-bound PAHs in a break room, downwind from a C-130H aircraft during a four-engine run-up test, in a maintenance hangar, in a C-130H aircraft cargo bay during cargo-drop training, downwind from aerospace ground equipment (AGE), and in a C-130H aircraft cargo bay during engine running on/off (ERO) loading and backup exercises. Two low-volume air samplers were collocated with the real-time monitors for all monitoring events except those in the break room and during in-flight activities. Total PAH concentrations in the integrated-air samples followed a general trend: downwind from two AGE units > ERO-loading exercise > four-engine run-up test > maintenance hangar during taxi and takeoff > background measurements in maintenance hangar. Each PAH profile was dominated by naphthalene, the alkyl-substituted naphthalenes, and other PAHs expected to be in the vapor phase. Particle-bound PAHs, such as fluoranthene, pyrene, and benzo[a]pyrene, were also detected in some of the sample extracts. During flight-related exercises, total PAH concentrations in the integrated-air samples were 10?25 times higher than those commonly found in ambient air. Real-time monitor mean responses generally followed the integrated-air sample trends. These monitors provided a semi-quantitative temporal profile of ambient PAH concentrations and showed that PAH concentrations can fluctuate rapidly from a baseline level below 20 ng m-3 to > 4,000 ng m-3 during flight-related activities. Small handheld models of the PAS monitors exhibited potential for assessing incidental personal exposure to particle-bound PAHs in engine exhaust and for serving as a real-time dosimeter to indicate when respiratory protection is advisable.
This abstract has been subjected to Agency review and approved for publication.