Integrated Evaluation of Soil Pollution and Plant Bioaccumulation Using Multimetric Indices: A Case Study from the Rehova Copper Mine, Albania

This study evaluates soil and plant contamination by heavy metals lead (Pb), cadmium (Cd), nickel (Ni), copper (Cu), chromium (Cr), and zinc (Zn) in the Rehova Copper Mine area, Albania. Soil contamination was assessed using the pollution load index (PLI), geoaccumulation index (Igeo), contamination factor (CF), enrichment factor (EF), and potential ecological risk index (RI), while plant contamination was evaluated through bioaccumulation coefficients (BFC). Sixteen soil samples and three pine (Pinus spp.) samples, collected at varying distances from the mine, were analysed. The results identified Cu, Ni, and Cd as the dominant pollutants, with PLI > 1 in most locations and an extreme Igeo value for Cu at L8 (5.38). Nickel contamination was severe at L10 (Igeo = 4.71), L11 (Igeo = 4.12), and L15 (Igeo = 4.24). EF analysis confirmed moderate to high enrichment for Cu and Ni in specific sites, while RI indicated considerable ecological risk (RI > 300) at six locations. Bioaccumulation analysis revealed a bioaccumulation coefficient (BFC) greater than 1 for Pb within a 1 km radius, indicating effective uptake of lead by Pinus spp. and supporting its use as a reliable bioindicator of lead pollution. Spearman correlation showed a significant positive relationship (r = 1; p < 0.001) between Zn in soil and plants, and a strong negative correlation for Cu (r = -1; p < 0.001). To support decision-making, the PROMETHEE multi-criteria decision analysis method was applied to rank all sampling sites based on combined contamination indices and ecological risk, identifying L8, L10, and L11 as the most critical hotspots for remediation. These findings indicate severe heavy metal pollution in the Rehova Mine area, highlighting the urgent need for targeted rehabilitation and long-term monitoring.