The influence of mine effluents on the sediments of the Slana River

On the basis of the declared state of emergency and the request of the interdepartmental crisis team, a narrower professional working group was created to solve selected problems related to the discharge of mine waters into the Slana River. The State Geological Institute of Dionyz Stur focused on the survey of river sediments in the basin of the Slana River from the Siderit plant to the state border with Hungary. The goal was to map and assess the state of river sediments both qualitatively and quantitatively. This contribution presents selected interim results, which are gradually updated based on new knowledge from ongoing monitoring. Overall, it can be concluded that the processes of oxidation, transport and dilution in the river lead to a decrease in the contents of the mentioned indicators in the sediments with increasing distance from the outlet of mine waters. It is probably related to the gradual decrease in the dynamics of the Slana stream. Stabilization of the detected chemical contents in the sediments to approximately level of the contents of the reference sample can be observed for most of the monitored chemical indicators from approximately 40 km below the pollution source. From a temporal point of view, one can logically assume a shift of the increased concentrations of the observed indicators in the direction of flow, but at the same time they are diluted by the tributaries of the Slana. (authors)