Spatial distribution and speciation of lead around corroding bullets in a shooting range soil studied by micro-X-ray fluorescence and absorption spectroscopy

University of Chicago, Chicago, Illinois, United States
Environmental Science and Technology (Impact Factor: 5.48). 08/2005; 39(13):4808-15. DOI: 10.1021/es0482740
Source: PubMed

ABSTRACT We investigated the spatial distribution and speciation of Pb in the weathering crust and soil surrounding corroding metallic Pb bullets in a shooting range soil. The soil had a neutral pH, loamy texture, and was highly contaminated with Pb, with total Pb concentrations in the surface soil up to 68 000 mg kg(-1). Undisturbed soil samples containing corroding bullets were collected and embedded in resin, and polished sections were prepared for micro-X-ray fluorescence (micro-XRF) elemental mapping and micro-X-ray absorption near edge structure (micro-XANES) spectroscopy. Bullet weathering crust material was separated from the metallic Pb cores and analyzed by powder X-ray diffraction analysis. Our results show a steep decrease in total Pb concentrations from the bullet weathering crust into the surrounding soil matrix. The weathering crust consisted of a mixture of litharge [alpha-PbO], hydrocerussite [Pb3(CO3)2-(OH)2], and cerussite [PbCO3], with litharge dominating near the metallic Pb core and cerussite dominating in the outer crust, which is in contact with the soil matrix. On the basis of these results and thermodynamic considerations, we propose that the transition of Pb species after oxidation of Pb(O) to Pb(II) follows the sequence litharge --> hydrocerussite --> cerussite. Consequently, the solubility of cerussite limits the activity of Pb2+ in the soil solution in contact with weathering bullets to < or =1.28 x 10(-6) at pH 7, assuming that the CO2 partial pressure (PCO2) in the soil is equal or larger than in the atmosphere (PCO2 > or = 0.000 35 atm).

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Available from: Delphine Vantelon, May 15, 2014
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    • "Evidently, Pb and Cu are major elements of concern that cause serious heavy metal contamination in firing range soils. Lead and Cu concentrations in firing range soils can reach 20,000 mg/kg (Lin 1996; Stansley and Roscoe 1996; Dermatas et al. 2006) and 2,000 mg/kg, respectively (Vantelon et al. 2005) depending on length of range operations. There are more than 3,000 active small arms firing ranges in the USA (USEPA 2005) and approximately 1,400 active small arms firing ranges in Korea (MOE 2005). "
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    ABSTRACT: A stabilization/solidification treatment scheme was devised to stabilize Pb and Cu contaminated soil from a firing range using renewable waste resources as additives, namely waste oyster shells (WOS) and fly ash (FA). The WOS, serving as the primary stabilizing agent, was pre-treated at a high temperature to activate quicklime from calcite. Class C FA was used as a secondary additive along with the calcined oyster shells (COS). The effectiveness of the treatment was evaluated by means of the toxicity characteristic leaching procedure (TCLP) and the 0.1 M HCl extraction tests following a curing period of 28 days. The combined treatment with 10 wt% COS and 5 wt% FA cause a significant reduction in Pb (>98 %) and Cu (>96 %) leachability which was indicated by the results from both extraction tests (TCLP and 0.1 M HCl). Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analyses are used to investigate the mechanism responsible for Pb and Cu stabilization. SEM-EDX results indicate that effective Pb and Cu immobilization using the combined COS-FA treatment is most probably associated with ettringite and pozzolanic reaction products. The treatment results suggest that the combined COS-FA treatment is a cost effective method for the stabilization of firing range soil.
    Environmental Geochemistry and Health 05/2013; 35(6). DOI:10.1007/s10653-013-9528-9 · 2.57 Impact Factor
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    • "The main metals that we expect to find in this hunting field are generally Pb, Fe, Mn, Ni, Cu, As, and Sb. Lead, As, and Sb were the most critical contaminants at shooting ranges that were previously reported by other researchers (Sorvari 2007; Vantelon et al. 2005). All elements were analyzed using inductively coupled plasma (ICP) atomic emission spectroscopy. "
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    ABSTRACT: PurposeEnvironmental contamination of lead (Pb) in soils and sediments poses serious threats to human and ecological health. The objective of this study is to investigate the effect of seasonal dove sports hunting activities on Pb contamination in acid forest soils. Materials and methodsA grid sampling method was used to investigate the spatial distribution of Pb contamination in surface soils. Soils were analyzed for total metal(loid) concentration and characterized for physicochemical properties and mineralogy. Adsorption isotherm experiments were also conducted to understand the reactivity and retention capacity of Pb(II) in soils. Finally, synchrotron-based X-ray microprobe and X-ray absorption spectroscopy were used to understand the chemical speciation of Pb that controls the retention/release mechanisms of Pb in soils. Results and discussionThere was no excessive accumulation of Pb at the site. However, the concentration of Pb in surface soils was greater than the background level (<16mgkg−1). The contamination level of Pb was as high as 67mgkg−1 near a patch of corn field where lime was frequently applied. A microfocused X-ray microprobe analysis showed the presence of Pb pellet fragments that predominantly contain oxidized Pb(II), suggesting that oxidative dissolution was occurring in soils. Dissolved Pb(II) can be readily retained in soils up to ~3,600mgkg−1 via inner-sphere and outer-sphere surface complexation on carbon and aluminol functional groups of soil components, suggesting that partitioning reactions control the concentration of Pb in soil solution. ConclusionsThe fate of Pb is likely to be controlled by (1) oxidative dissolution process of Pb(0) pellets and (2) the release of outer-sphere and/or inner-sphere Pb surface complexes in humic substances and aluminosilicate/Al oxyhydroxides. Although no remedial actions are immediately required, the long-term accumulation of Pb in soils should be carefully monitored in protecting ecosystem and water quality at the dove hunting field. KeywordsAmmunition–Chemical speciation–Contamination–Fate–Lead–Soil–XAS–X-ray microprobe
    Journal of Soils and Sediments 09/2011; 11(6):968-979. DOI:10.1007/s11368-011-0374-z · 2.11 Impact Factor
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    • "In shooting range soils, the oxidation and eventual carbonation of metallic lead (Hardison et al., 2007) is responsible for the high proportion of lead being associated with carbonates. A previous study showed that the crusts of weathered bullets consisted of a mixture of litharge (a-PbO), hydrocerrusite [Pb 3 (CO 3 ) 2 (OH) 2 ] and cerrusite (PbCO 3 ) (Vantelon et al., 2005). They proposed that the transition of Pb species after Pb oxidation follows the sequence of litharge to cerussite and to hydrocerussite. "
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    ABSTRACT: To better understand the environmental impact of lead (Pb) in shooting range soils, Pb levels in three berm soils were characterized via size distribution, total Pb concentration, water-soluble Pb, sequential extraction and X-ray diffraction (XRD). About 60% of the mid-berm soils of ranges-G and -O existed in grain sizes between 0.5 and 0.25 mm (medium sand) while range-L was most abundant in the 0.25 - 0.106 mm (fine sand) size fraction. All three range soils had the most accumulation of lead (60 - 70%) in the very coarse sand size (2.0 - 1.0 mm). In ranges-G and -L, the index shows a decreasing Pb enrichment with decreasing particle size, which may be a result of bullet fragmentation and abrasion in shooting range soils. Sequential extractions reveal that ranges-G and -L had the highest proportion of Pb bound to organic matter while range-O was dominated by the carbonate-bound fraction. However, a substantial proportion (one-third) of Pb in soil from the three shooting ranges was associated with carbonates. The XRD result revealed the dominance of carbonates in range-O soil, calcite in range-G soil and metallic lead in ranges-G and -O soil. The conversion of metallic lead to carbonates may be a mechanism for natural attenuation of lead in shooting range soils. Implications for remediation of shooting range soils are further discussed.
    Chemical Speciation and Bioavailability 07/2011; 23(3):163-169. DOI:10.3184/095422911X13103191328195 · 0.38 Impact Factor
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