In spite of the environmental significance of copper, very few studies are available on the speciation, bioavailability, and toxicity of copper in the soils of Chile and the Aconcagua River basin in particular. The objective of the present study is to determine the seasonal dynamics of solution- and solid-phase speciation of copper in studied soils and to analyze the factors affecting copper speciation and mobility in soils. Soils impacted by mining activities are a potential source of contamination of surface waters with toxic trace elements (and copper in particular). Pollution of surface waters with copper, in turn, could affect negatively the microbial processes in soil-water system. Diversity of aquatic organisms could be affected negatively as well. The proposed study will elucidate the factors affecting the speciation and mobility of Cu in soil-water system.