IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 154 Environment, Agriculture, and Forestry Friday, 28 August 2026 / Hall C SL78 Organic matter contribution in the dynamic contamination of gunshot residue (GSR) in soils of sports shooting clubs Maria Eduarda Silva Gonçalves1, Matheus Rodrigues Moraes1, Felipe Ramom Freitas Cabral1, Ramom Rachide Nunes1 1 Laboratory of Environmental Chemistry, Department of Chemistry, Federal Rural University of Pernambuco. Recife, Brazil. Dom Manoel de Medeiros Street, no number, Recife, Pernambuco, 52171-900, Brazil. ramom.rachide@ufrpe.br The increase in the number of shooting clubs, driven by political movements that promote gun culture, raises environmental concerns within a One Health framework. Gunshot residues (GSR) are rich in toxic elements (e.g., Cr, Mn, Ni, Cu, Zn, Cd, Pb, As, Hg, and Sb) and pose risks to humans, plants, and particularly soils due to their high toxicity [1]. These elements interact with soil constituents, especially organic matter (OM), which plays a key role in the geochemical dynamics of contaminants, influencing mobility and bioavailability [2]. Although previous studies demonstrate that firearm activity contaminates soils and the edaphic environment, they often lack robust metrics to quantify contamination. In this study, contamination indices were applied to assess environmental impact, enabling classification of contamination severity and evaluation of the relationship between OM content and retention of toxic elements in the soil cover. Thus, this study aimed to evaluate the contribution of organic matter to GSR-derived contamination in soils from sports shooting ranges. Soil samples were collected at a shooting club in Recife (Brazil), across three shooting ranges (SR) and two depth intervals: cover soil (CS: 0–2 cm) and soil (S: 2–20 cm). A control sample (CTRL) was also collected. Samples were analyzed for DM, OM, TOC, pH, and EC. Toxic elements were quantified using EDXRF. The enrichment factor (EF), geoaccumulation index (Igeo), pollution load index (PLI), and combined pollution index (CPI) were calculated. PCA was applied to identify patterns and reduce dimensionality. pH ranged from 5.60 to 10.27 and was higher in SR than CTRL, indicating alteration of soil chemical properties. Since pH influences metal mobility, bioavailability, and sorption, these changes have geochemical implications [2]. OM ranged from 1.36% to 4.82%, with a 45% increase in soil samples (SR/S) compared to cover samples (SR/CS). Pb reached the highest concentrations (up to 2763 mg kg⁻¹), indicating significant accumulation and risk. Cr and Mn also showed elevated concentrations (3072 mg kg⁻¹ and 10 mg kg⁻¹, respectively). Other elements, such as Sb and As, were determined at lower concentrations. The
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