Soil geochemical spatial distribution trend of heavy metals in the Kimmeria Public Mining Area, Northern GreeceSoil geochemical spatial distribution trend of heavy metals in the Kimmeria Public Mining Area, Northern Greece

Heavy metals are released into the environment by both natural and anthropogenic sources and can potentially be toxic. Many of these metals are enriched in areas hosting ore deposits; their spatial distribution trend is critical for evaluating the environmental impact. This study records the soil geochemical signature in the southern part of the Public Mining Area of Kimmeria, northern Greece, and aims to form the basis of an integrated geochemical baseline study, prior to any future mining activities. The study area lies within the Rhodope Massif and hosts the Kimmeria magmatic-hydrothermal system, which is associated with the Xanthi pluton. It comprises two major ore types: i) a Fe-Cu±W±Bi±Mo±Au skarn and ii) a Mo-Cu±Au vein-hosted mineralization, mostly concentrated in the northern edge of the study area. Fourty-six surface samples (0-20 cm depth) were collected, covering an area of about 2,5 km², and detailed mapping of the existing environmental pressures was carried out. The contents of As, Bi, Cr, Cu, Mn, Mo, Ni, Pb, Sn, W, and Zn were measured using ICP-MS, while Fe₂0₃ values were obtained by XRF at the analytical laboratories of HSGME. Statistical analysis and spatial interpolation were performed using Microsoft Excel 365 MSO and ArcGIS 10.8.1 software. The spatial distribution patterns reveal certain groups of elements, i.e., Fe₂0₃-Cu-Bi-W, Mo-W-Zn, that display significant to very strong positive Pearson correlation coefficients (e.g., Bi-Cu, Bi-W, Mo-W, Mo-Zn, Cu- Fe₂0₃, and Mn-Zn). These groups reflect the availability of these elements with respect to the major types of mineralization, with relevant spatial and linear trends. These data suggest common geological sources, also supported by the mineralogical and mineral-chemical remarks. Notably, As exhibits poor correlation suggesting spatially controlled factors (e.g., substituting element in minor phases like pyrite). Samples and data analysis are still in progress and the final trends are expected to be delineated.