SR μXRF and XRD study of the spatial distribution and mineralogical composition of Pb and Sb species in weathering crust of corroded bullets of hunting fields

• We studied the weathered bullets collected in dove hunting fields of the forest region in the north of Córdoba, Argentina.
• Synchrotron radiation micro XRF and XRD were used in samples of bullets and crust.
• We quantified the elemental and mineral composition of crust finding 4 mineral compounds of Sb and 8 compounds for Pb.
• SR-μXRF mapping of weathered bullets show affinity of soil metallic oxides to grow mineral phases of Sb and Pb.
• XRD patterns of crust show the influence of P-based fertilizers used in agriculture in the formation of Hydroxypyromorphite.

The spatial distribution of Pb and Sb in core and crust material and the mineralogical composition of these elements in weathering crust of corroded bullets found in hunting fields were investigated. Lead, antimony and others metals from pellets alloy are disperse in the soil of the shooting fields. As long as the corroding bullets are present in soil, secondary Pb and Sb phases appear in the weathering crusts being an important source of bioavailable Pb and Sb.Powder X-ray diffraction (XRD) patterns of crust material from weathered bullets showed encrustation of relevant Pb and Sb phases like: hydrocerussite (Pb3(CO3)2(OH)2), litharge (PbO-tetragonal), hydroxypyromorphite (Pb5(PO4)3(OH)), gebhardite (Pb8OCl6(As2O5)2, Sb metallic, stibnite (Sb2S3), tripuhyite (FeSbO4) and potassium sodium antimony oxide (KO13Sb5) among others minor compounds.The chemical elemental distribution of corroded bullets was determined by synchrotron radiation-induced micro X-ray fluorescence analysis (SR-μXRF). A positive correlation between Sb and Fe was detected in crust material measured in the outer rim of the weathered bullets due to Sb adsorption to Fe oxyhydroxides of soil. It was also observed a spatial correlation between Sb and Cu and between Sb and Zn in crust. The influence of phosphorus applied as (P)-based fertilizers of soils was observed in the hydroxypyromorphite phase detected in samples collected near agricultural lands.