Modeling speciation, transport and transformation of metals from mine wastes

This paper describes the results of modeling studies on transformation and speciation of metals within a river basin contaminated by mining wastes. New methods for estimating contaminant transformation on a comprehensive river basin based on assembled subsite behaviors are demonstrated for a collection of Hazardous Waste Sites mandated for clean up under the special act of United States Congress, commonly referred to as Superfund sites in the Upper Clark Fork River, south-western Montana, USA. A linked assessment system — consisting of contaminant transformation, Non-Point Source (NPS) and groundwater mixing and transport, surface hydrology and erosion, and surface-water quality models — has been developed, tested, and applied at the site. The main focus of this paper is development and application of site-specific models for metal speciation and tranformation processes. Results of metals speciation modeling, specifically copper, indicate that metal oxides, hydroxides, carbonates, and sulfates are precipitates that control the availability of heavy metal solutes for transport.