30th Annual SSRL Users' Meeting — October 9-10, 2003

Synchrotron Radiation Study of Pb and As in Air Filter Particulate Matter

X. C. Kretschmer and N. E. Pingitore, Jr.

The Department of Geological Sciences, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968-0555

El Paso and Ciudad Juarez are neighboring cities on the U.S.--Mexico border that historically have experienced particulate matter (PM) pollution of their shared airshed. Pb and As are important pollutants present in the particulate matter fraction trapped by air sampling filters. We examined air filters from as early as 1977 to as recently as 2001 to determine the oxidation state and speciation of As and Pb present on these filters. We believe that the lead found on these air filters has three possible major sources: a local copper smelter, leaded gasoline (in use until approximately 1990 in Mexico), and a mixed general urban lead input. Information on the chemical speciation of Pb and As is important in determining bioavailability, fate, and possible sources of these contaminants.