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CONCENTRATIONS AND SOLUBILITY OF METALS FROM INDOOR AND PERSONAL EXPOSURE PM2.5 SAMPLES
Citation:
Graney, J. R., M S. Landis, AND G A. Norris. CONCENTRATIONS AND SOLUBILITY OF METALS FROM INDOOR AND PERSONAL EXPOSURE PM2.5 SAMPLES. ATMOSPHERIC ENVIRONMENT 38(2):237-247, (2004).
Impact/Purpose:
The overall research objective of this task is to improve our understanding of the emission, transport, transformation, and deposition of atmospheric mercury. Information garnered from this research is used to improve and evaluate EPA deterministic models that are used to investigate the (i) relative impact to local, regional, and global sources to atmospheric mercury deposition, and (ii) benefits of various emission reduction scenarios.
Specifically, individual research project objectives are listed below:
(1) Evaluate the ability of speciated mercury (Hg0, Hg2+, HgP) measurements to aid source apportionment models in identifying anthropogenic source contributions to atmospheric mercury deposition
(2) Elucidate the contribution of coal combustion sources to observed mercury wet deposition in the Ohio River Valley
(3) Obtain atmospheric profiles (200 - 12,000 ft) of speciated ambient mercury off the south Florida Coast
- Evaluate the role of long range transport of RGM to Florida in the marine free troposphere.
- Identify any vertical mercury gradients that might indicate the presence of rapid mercury chemistry in air or in cloud water.
(4) Conduct research at Mauna Loa Observatory to elucidate elemental mercury oxidation in the remote marine free troposphere.
(5) Conduct laboratory kinetics experiments to determine the rate constants of elemental mercury oxidation to gaseous inorganic divalent mercury species from atmospheric halide species (e.g. BrO, ClO).
Description:
An assessment of trace metal quantification capabilities for indoor (123 ± 53 μg; mean ± standard deviation of particle mass) and personal exposure (32 ± 12 μg) PM2.5 samples from Baltimore, MD was undertaken as part of an EPA study investigating health effects associated with particulate matter. This study included determination of total PM2.5 metal concentrations by energy dispersive x-ray fluorescence (XRF), instrumental neutron activation analysis (INAA), and method development to quantify amounts of water and acid extractable metals from PM2.5 using inductively coupled plasma-mass spectrometry (ICP-MS). Analytical uncertainties, filter blank contributions, and sample preparation were all found to significantly impact quantification limits. The ICP-MS leaching procedure resulted in partial extraction of metals from the PM2.5. Most of the extractable component of the metals was in a water-soluble form suggesting a high potential for bioavailability of elements from respiratory exposure to PM2.5. A comparison of PM2.5 trace metal concentrations from indoor air samples collected from a central indoor site versus concurrently collected personal exposure samples indicates that resident activities result in exposure to higher concentrations of soluble trace metals.
This work as been funded wholly or in part by the U.S. Environmental Protection Agency Office of Research and Development. It has been subjected to Agency Review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.