Metal Pollution Assessment of Surface Water in the Emission Field of the Slovinky Tailing Impoundment (Slovakia)

Abstract

The focus of this work is on the evaluation of selected water quality indicators as per the applicable regulations, taking into account European and national legislation and the evaluation of the risk of contamination of surface waters with toxic elements using the contamination factor (Cfi) and the degree of pollution (Cd). The studied area of Slovinky is an important ore region, with rich deposits of copper and silver ores that have been mined for centuries. One of the most important remnants of mining activities in this area is the Slovinky tailing impoundment. The sludge pond area has an area of 15 ha, and the height of the dam is 113 m above sea level, which makes the sludge pond one of the tallest water structures in Slovakia. The Slovinský creek was monitored in the years 2010, 2011, and 2019 at five sampling points, which were selected to map the entire length of the water flow from the source to the estuary to the river Hornád. Risk elements (As, Cu, Cd, and Fe) and physicochemical parameters (such as temperature, dissolved oxygen concentration, conductivity, resistivity, salinity, total dissolved solids, NaCl, redox potential, and pH) were included in this study and evaluated according to applicable regulations, taking into account European legislation (Act No. 269/2010 Coll., guideline value WHO 2011). The results of the experimental studies showed that the highest values of As and Cu were measured at the site where drainage waters from the Slovinky tailing impoundment and mining water of the Alžbeta shaft flow into the creek. The concentration of As exceeded the limit value by up to 31 times and the concentration of Cu 16.8–134.5 times. At the same time, the highest values of conductivity, salinity, total dissolved solids, and NaCl were found, and there was no acidification of water at the site that had the highest pollution. Water contamination was assessed based on Cfi and Cd; our findings showed that the surface water from the site of contamination, along the entire length of the stream, was very highly contaminated with risk elements in the order of As > Fe > Cu, and the level of contamination decreased with distance from the site of contamination. Our research shows that seepage of toxic substances from sludge ponds and abandoned mines has caused the requirements for the quality of surface water of the Slovinský creek not to be met. In connection with mining activities, surface streams act as a transport medium through which other components of the environment can be polluted.