Characterizing Mineral Dusts and Other Aerosols from the Middle East—Part 2: Grab Samples and Re-Suspensions

Abstract

The purpose of the Enhanced Particulate Matter Surveillance Program was to provide scientifically founded information on the chemical and physical properties of dust collected during a period of approximately 1 year in Djibouti, Afghanistan (Bagram, Khowst), Qatar, United Arab Emirates, Iraq (Balad, Baghdad, Tallil, Tikrit, Taji, Al Asad), and Kuwait (northern, central, coastal, and southern regions). To fully understand mineral dusts, their chemical and physical properties, as well as mineralogical inter-relationships, were accurately established. In addition to the ambient samples, bulk soil samples were collected at each of the 15 sites. In each case, approximately 1kg of soil from the top 10 mm at a previously undisturbed area near the aerosol sampling site was collected. The samples were air-dried and sample splits taken for soil analysis. Further sample splits were sieved to separate the < 38 μ m particle fractions for mineralogical analysis. Examples of major-element and trace-element chemistry, mineralogy, and other physical properties of the 15 grab samples are presented. The purpose of the trace-element analysis was to measure levels of potentially harmful metals while the major-element and ion-chemistry analyses provided an estimate of mineral components. X-ray diffractometry provided a measure of the mineral content of the dust. Scanning electron microscopy with energy dispersive spectroscopy was used to analyze chemical composition of small individual particles. From similarities in the chemistry and mineralogy of re-suspended and ambient sample sets, it is evident that portions of the ambient dust are from local soils.

ACKNOWLEDGMENTS

We acknowledge contributions by the military public-health soldiers, sailors, and airmen whose efforts were necessary to complete the Enhanced Particulate Matter Surveillance Program (EPMSP). The dedicated effort shown by all participating units in the field, who operated the sampling equipment and collected filter and grab samples, is greatly appreciated. We acknowledge major contributions from the two collaborating laboratories: RTI International, for the ICP-MS analysis of the 30 re-suspended filter samples; and RJ Lee Group Inc. (specifically Traci Lersch for the CCSEM and SEM individual particle analysis). Thanks are also due to several researchers at DRI who contributed their expertise to the analyses and this report: Michał Skiba for the XRD analysis; Todd Caldwell for analysis of the 15 < 1000 μ m sieved soil samples; and Steve Kohl for the EDXRF, ion, and carbon analyses of the 30 re-suspended filter samples. Finally, the following individuals deserve special recognition for their contributions: Greta Engelbrecht, for dedicated hours spent on data validation, compilation of results, and providing graphical representations; and James Sheehy and John Kolivosky of USACHPPM, for their support from the inception of the Enhanced Particulate Matter Surveillance Program to its completion. The project was funded under the US Department of Defense contract number W9124R-05-C-0135/SUBCLIN 000101-ACRN-AB