| Autor: |
De Santiago A; School of Earth and Atmospheric Sciences, Georgia Institute of Technology , 311 Ferst Drive, Atlanta, Georgia 30332-0340, United States., Longo AF, Ingall ED, Diaz JM, King LE, Lai B, Weber RJ, Russell AG, Oakes M |
| Jazyk: |
angličtina |
| Zdroj: |
Environmental science & technology [Environ Sci Technol] 2014 Aug 19; Vol. 48 (16), pp. 8988-94. Date of Electronic Publication: 2014 Aug 07. |
| DOI: |
10.1021/es500379y |
| Abstrakt: |
Atmospheric selenium (Se) in aerosols was investigated using X-ray absorption near-edge structure (XANES) spectroscopy and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the oxidation state and elemental associations of Se in common primary emission sources and ambient aerosols collected from the greater Atlanta area. In the majority of ambient aerosol and primary emission source samples, the spectroscopic patterns as well as the absence of elemental correlations suggest Se is in an elemental, organic, or oxide form. XRF microscopy revealed numerous Se-rich particles, or hotspots, accounting on average for ∼16% of the total Se in ambient aerosols. Hotspots contained primarily Se(0)/Se(-II). However, larger, bulk spectroscopic characterizations revealed Se(IV) as the dominant oxidation state in ambient aerosol, followed by Se(0)/Se(-II) and Se(VI). Se(IV) was the only observed oxidation state in gasoline, diesel, and coal fly ash, while biomass burning contained a combination of Se(0)/Se(-II) and Se(IV). Although the majority of Se in aerosols was in the most toxic form, the Se concentration is well below the California Environmental Protection Agency chronic exposure limit (∼20000 ng/m(3)). |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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