50 years of mining-induced environmental changes: topography, hydrology, and vegetation health in Kazreti, Georgia

Abstract

Globally, prioritizing short-term economic gains from mineral extraction has led to a critical dilemma: a planet rich in resources struggles with environmental degradation and a diminishing ability to sustain future generations. Open-pit mining exemplifies this paradox, causing significant environmental damage. In Georgia, this extractive industry presents environmental problems. Despite these known consequences, the long-term impacts of mining activities remain understudied. This study addressed this gap by analyzing the effects of open-pit mining on terrain morphology, and water dynamics in the Kazreti region over a 50-year period (1970–2020) and vegetation health over 35-year period (1987–2022). By integrating water quality assessment, spatial analysis and remote sensing, we revealed the significant human-induced changes to the region’s ecosystem. Spatial analysis results suggested that over 156.7 million cubic meters of bedrock have been fragmented by mining in southern East Georgia, with 125.5 million cubic meters deposited in valleys. Consequently, discernible shifts in the trajectories of water flow were observed based on the hydrological model. Additionally, a comparative analysis of NDVI and EVI values revealed a decline in vegetation health near mining zones, while remote forest areas remained stable. June typically showed healthier vegetation due to cooler temperatures and optimal growing conditions, while August presented lower vegetation health due to increased heat stress. Water quality revealed significant loadings of Cu (58–1855 μg l−1), Zn (54–2582 μg l−1), Mn (1–2167 μg l−1), and Cd (0.1–4.5 μg l−1), in local river systems, which are higher than the Georgian official guideline values (Cu - 1000, Zn - 1000, Mn—100, Cd—1 μg l−1). This study highlighted the need for a broader long-term monitoring strategy to assess the migration of these contaminants within the food web and the consequent socio-economic impact.