Impact of Former Mining Activity to Soil Contamination by Risk Elements

The level of contamination of the environment in the past few decades is largely influenced by the anthropogenic activity. Among the most burdened areas by the remains of the mining and processing industry in the middle Spiš region, where was treated by mercury - containing ore (cinnabar and tetraedrite) from the middle of 20th century to 1993. About 500 meters from the main processing plant is located tailing pond where landfilled flotation sludge with the content of mercury is more than 46 mg/kg. In the present work, we have focused on the assessment of the level of contamination of the upper horizon (0-0.1 m) of agricultural and forest land in the cadastral territory of Markušovce, where is located the emission source and the pond. We determined 28 sampling points by GPS method on areas of our interest. All soil samples have been subjected to analyses for the detection of the active and the exchange of the soil reaction, the content of humus (%), total concentration of Hg and the concentrations of Cd, Pb, Cu and Zn (mg/kg) in the solution of the aqua regia. The results obtained an extremely high level of contamination of these elements of the contents of the soil. Mercury concentration was in the range of 0.69-90.7 mg/kg, while the median value was recorded exceeding the standard established by applicable legislation over 30 times. The content of other heavy metals closely correlated with contaminant concentration, which varied in wide intervals as evidenced by high relative standard deviations (Cd: 1.62 ± 34.2 mg/kg; Pb: 37.6 ± 60.7 mg/kg; Cu: 23.5 ± 124 mg/kg Zn: 108 ± 40.4 mg/kg). Even in the case of these two elements we have in excess of the limit value at the level of the averages. The results observed that heavy metal concentrations indicate a high level of soil contamination in the study area, which will be reflected to the contamination of other components of environment and food chain.