The diploma thesis deals with the environmental safety of the Mežica valley, for which elevated values of heavy metals are known as a result of many years of mining and processing of lead-zinc ore. We discussed the impact of the degraded environment and possible harmful effects on the lives of the inhabitants of the Mežica valley. In the experimental part, the content of arsenic, cadmium, cobalt, chromium, copper, molybdenum, nickel, lead, selenium and zinc was determined in five samples of water and sediment of the Meža river. The content of selected heavy metals was measured with the analytical technique of inductively coupled plasma optical emission spectrometry (ICP-OES). Sampling and analysis were performed in March 2022.
The obtained concentrations of heavy metals in surface waters and sediment were compared with the Slovenian threshold values and the threshold values of some other countries and organizations. Measurements of surface water samples showed that the maximum permissible concentrations (NDK-OSK), which are set in Slovenian legislation, were in no case exceeded. The exception is cadmium, where concentrations were below the limit of quantification, so comparison with some limit values was not possible. The same problem was encountered at individual sampling sites for some other investigated elements. In the surface water of the Meža river, the copper concentration stood out slightly, because they were elevated at all sampling sites.
In the sediment of the Meža river, the concentrations of cadmium, lead and zinc at individual sampling points exceed the critical immission values set out in Slovenian legislation. Based on our measurements, we found out that the most polluted sediment is in Mežica. We also determined geo-accumulation index, contamination factors, enrichment factors and pollutant load index, where the measured concentrations are in different ways compared to naturally occurring concentrations of heavy metals in the environment. The results prove that the pollution of the Meža River is still present, which confirms the fact that the risk to the ecosystem and the health of the surrounding population remains.