Article

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: 5.33). 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).

Download full-text

Full-text

Available from: Delphine Vantelon, May 15, 2014
  • Source
    • "In soil, Pb(II) soil is present in the form of different chemical species of increasing stability until reaching highly stable mineral forms (Lin et al., 1995; Cao et al., 2003; Vantelon et al., 2005; Jensen et al., 2006; Torri and Lavado, 2008; Ferreyroa et al., 2014). The most commonly found mineral forms are massicot or litharge (PbO), cerussite (PbCO 3 ) and hydrocerussite (Pb 3 (CO 3 ) 2 (OH) 2 ) (Cao et al., 2003; Vantelon et al., 2005; Hashimoto et al., 2011; Hashimoto, 2013). These transformation processes result in an important increase of the pollutant in soil, water, and vegetation (Cao et al., 2003), often making it totally or partially bioavailable for its incorporation into the food chains (Guitart and Thomas, 2005; Dickerson et al., 2007). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The pollution of wetlands by lead derived from waterfowl hunting with lead shot was investigated. We determined soil pellet density and Pb concentration in soil, water and vegetation in natural wetlands and rice fields in central-eastern Santa Fe province, Argentina. Pellet density varied greatly among hunting sites (between 5.5-141 pellets/m(2)) and pellets were present in some control sites. Soil Pb concentration in most hunting sites (approximately 10-20mgkg(-1)) was not much higher than in control sites (~5-10mgkg(-1)), with the exception of the site with highest pellet density, which also had a high Pb soil concentration. In water, on the other hand, Pb concentration was similar in all sites (~4-7μgL(-1)), both control and hunting, and higher than reference values for aquatic media. Lead was also present in vegetation, including grasses and rice crops, in almost all cases. Most soil-collection sites were slightly acidic, and were frequently flooded. These results strongly suggest that metallic Pb from spent shot is oxidized and dissolved due to wetland conditions. Thus, the pollutant is readily mobilized and distributed across all wetland areas, effectively homogenizing its concentration in locations with and without hunting activities. The replacement of lead by nontoxic materials in pellets appears to be the only effective way to prevent Pb pollution in wetlands.
    Full-text · Article · Mar 2016 · Science of The Total Environment
  • Source
    • "These phases are on the outer crust that covers ammunition, and their formation is favoured by acidity, organic matter, available P and microbial activity as well as by dissolved CaCO3 coming from the clay target residues (Lin 1996; Cotter-Howells et al. 1999; Hashimoto 2013). The difficulty in identifying the aforementioned phases is because the amount formed is scarce and they are usually not well crystallized (Vantelon et al. 2005; Ma et al. 2007). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Pb pollution caused by shooting sport activities is a serious environmental problem that has increased considerably in recent decades. The aims of this study were firstly to analyze Pb pollution in soils from a trap shooting range abandoned in 1999, secondly to study the effectiveness of different extractants [CaCl2, DTPA, NH4OAc, low molecular weight organic acids (LMWOA), and bidistilled water (BDW)] in order to determine Pb bioavailability in these soils, and finally to evaluate the phytoremediation ability of spontaneous vegetation (Agrostis capillaris L.). To this end, 13 soils from an old trap shooting range (Galicia, NW Spain) were studied. It was found that Pb levels in the soils were higher than 100 mg kg(-1), exceeding the generic reference levels, and three of these samples even exceeded the USEPA threshold level (400 mg kg(-1)). In general, the reagent that best represents Pb bioavailability and has the greatest extraction efficiency was CaCl2, followed by DTPA, NH4OAc, LMWOA, and BDW. A. capillaris Pb contents ranged between 9.82 and 1107.42 mg kg(-1) (root) and between 6.43 and 135.23 mg kg(-1) (shoot). Pb accumulation in roots, as well as the presence of secondary mineral phases of metallic Pb in the adjacent soil, showed the phytostabilization properties of A. capillaris.
    Full-text · Article · Jan 2016 · Environmental Science and Pollution Research
  • Source
    • "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). "
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · May 2013 · Environmental Geochemistry and Health
Show more