Spatial Distribution and Speciation of Lead around Corroding Bullets in a Shooting Range Soil Studied by Micro-X-ray Fluorescence and Absorption Spectroscopy
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- 作者：Delphine Vantelon ; Antonio Lanzirotti ; Andreas C. Scheinost ; and Ruben Kretzschmar
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：July 1, 2005
- 年：2005
- 卷：39
- 期：13
- 页码：4808 - 4815
- 全文大小：638K
- 年卷期：v.39,no.13(July 1, 2005)
- ISSN：1520-5851
文摘
We investigated the spatial distribution and speciation ofPb in the weathering crust and soil surrounding corrodingmetallic Pb bullets in a shooting range soil. The soil hada neutral pH, loamy texture, and was highly contaminatedwith Pb, with total Pb concentrations in the surface soilup to 68 000 mg kg-1. Undisturbed soil samples containingcorroding bullets were collected and embedded in resin,and polished sections were prepared for micro-X-rayfluorescence (
-XRF) elemental mapping and micro-X-rayabsorption near edge structure (-XANES) spectroscopy.Bullet weathering crust material was separated from themetallic Pb cores and analyzed by powder X-ray diffractionanalysis. Our results show a steep decrease in total Pbconcentrations from the bullet weathering crust into thesurrounding soil matrix. The weathering crust consisted ofa mixture of litharge [
-PbO], hydrocerussite [Pb3(CO3)2(OH)2], and cerussite [PbCO3], with litharge dominating nearthe metallic Pb core and cerussite dominating in theouter crust, which is in contact with the soil matrix. Onthe basis of these results and thermodynamic considerations,we propose that the transition of Pb species afteroxidation of Pb(0) to Pb(II) follows the sequence litharge
hydrocerussite cerussite. Consequently, the solubilityof cerussite limits the activity of Pb2+ in the soil solutionin contact with weathering bullets to 
1.28 × 10-6 at pH 7,assuming that the CO2 partial pressure (PCO2) in the soilis equal or larger than in the atmosphere (PCO2 
0.000 35atm).
-XRF) elemental mapping and micro-X-rayabsorption near edge structure (-XANES) spectroscopy.Bullet weathering crust material was separated from themetallic Pb cores and analyzed by powder X-ray diffractionanalysis. Our results show a steep decrease in total Pbconcentrations from the bullet weathering crust into thesurrounding soil matrix. The weathering crust consisted ofa mixture of litharge [-PbO], hydrocerussite [Pb3(CO3)2(OH)2], and cerussite [PbCO3], with litharge dominating nearthe metallic Pb core and cerussite dominating in theouter crust, which is in contact with the soil matrix. Onthe basis of these results and thermodynamic considerations,we propose that the transition of Pb species afteroxidation of Pb(0) to Pb(II) follows the sequence litharge hydrocerussite cerussite. Consequently, the solubilityof cerussite limits the activity of Pb2+ in the soil solutionin contact with weathering bullets to 1.28 × 10-6 at pH 7,assuming that the CO2 partial pressure (PCO2) in the soilis equal or larger than in the atmosphere (PCO2 0.000 35atm).