Ore-bearing rocks and natural waters of the Pitkäranta ore district (near the “Arsenic” shaft, the Hopunvaara mine field) were sampled and analyzed. The permanganate value as well as iron and manganese contents in surface water are higher than MPC values, while water samples from the “Arsenic” shaft have the elevated contents of zinc, copper, and arsenic. The Fe, Mn, Cu, Zn, Cr, As, and Ni speciation in waters have been determined by thermodynamic calculations, taking into account the possibility of the formation of metal complexes with humic and fulvic acids. The fulvic acid is almost completely consumed for the formation of the complex Fe(OH)₂Fu^-. Ni, Cd, Co occur mainly in the ionic form, and the fraction of Mn and Zn in the ionic form is also significant.

Abandoned mines are sources of potentially toxic chemical elements, although the development of these objects was completed. The Lupikko I mine area (Karelia Republic, Russia) is an excellent example of such technogenic objects. It is one of the largest mines in the Pitkäranta area, which was abandoned more than one hundred years ago. The dump rocks here are characterized by significant mineral diversity. Disseminated ore mineralization of the study area contains heavy metals, which enter the natural waters due to the oxidative dissolution of sulfides. Dump rocks and water from the Lupikko I mine area were collected to research the behavior of toxic elements. The samples were analyzed using ICP-MS, ICP-AES, potentiometric titration, ionic chromatography, X-ray microanalysis, X-ray fluorescence, and SEM to obtain information about the geochemical environment. According to new data, the content of Fe, Zn, Cu, Pb, Cd, and Ni in the natural waters of the mine significantly exceeds the geochemical background. For a more detailed study of the behavior of heavy metals, equilibrium-kinetic modeling, which considers the dissolution rate of ore minerals and the accumulation of toxic elements over time, was applied. A comparison of modeling data and field observations agreed. It was also found that for accurate modeling of Fe behavior, it is necessary to consider the organic matter content. Despite some model limitations, such retrospective assessments allow us to approve the applicability of this method for forecasting estimates.

The technogenic impact of the development of the Lomonosov diamond deposit is associated with the discharge of quarry and drainage water into the river, which has a special conservation status. Earlier studies on the composition of bottom sediments showed that there are signs of increased accumulation of heavy metals and radionuclides at wastewater discharge sites. The purpose of this work was to predict changes in the composition of surface water and bottom sediment in the river during the further development of mining operations with brackish and salty water captured by drainage systems, the presence of which was established in the zone of their future influence. For this, a simulation of changes in the composition of the water in the river was carried out using the GEOCHEQ software package by minimizing the free energy of the system using a convex simplex algorithm. It was found that the maximum salinity of surface water can reach 1.51 g/L. In this case, the MPC of Cl⁻, Na⁺, SO₄²⁻, Mg²⁺, Sr, V, and U can be exceeded for fishery watercourses. The genetic basis of the accumulation of these components in solutions for mixing was considered. According to the calculations, when about 5000 m³/h of drainage water is discharge d into the river, the mass of precipitated chemical elements will be 56–191 t/h, including up to 2.1 t/h of iron; therefore, accumulation in the discharge zone must be controlled.

The paper presents certain aspects of applying equilibrium-kinetic modeling to preliminarily assess the formation of the chemical composition of sewage subdump waters during upcoming mining at the Udokan deposit. The mineral dissolution rates, including oxidative dissolution of sulfides, and sorption of strontium, cobalt, zinc, and nickel on calcite are taken into account. It is shown that the chemical composition of water during interaction with dump rocks changes very slowly. However, such heavy metals as nickel, zinc, cobalt, and molybdenum should accumulate in the aqueous solution of the settling pond within 50 years.