REPOSITORY > RESULTS

Abstract

Knowledge of the pollution activity at the mining and smelting sites and assessment of contamination levels at different sites is not always sufficient for reliable conclusions regarding lead (Pb) provenance and contributions from sources. Pb isotopes have long been used as ‘fingerprints’ of the source of Pb recorded in environmental archives, as its isotope composition is not significantly affected by physical-chemical fractionation processes.
Due to the long and intensive mining and processing activities of Pb and zinc (Zn) in the Upper Meža Valley, the area is excessively polluted with Pb, Zn, cadmium (Cd), and other potentially toxic elements (PTEs). After the closure of the mine and smelter and the introduction of severe remedial measures, the burden on the environment and people began to decrease. However, in recent years, a re-release of Pb and other PTEs has been observed. The focus of previous research in the Upper Meža Valley was mostly on the load of the environment with Pb and its distribution in the environment, while a more detailed study about the source apportionment of Pb in airborne particulate matter, with a diameter smaller than 10 μm (PM10) and an assessment of the contribution of individual sources has not yet been done.
Therefore, the main purpose of the dissertation was to determine the source of Pb in PM10 from the Upper Meža Valley by applying advanced analytical techniques. First, the analytical method for the determination of Pb isotope composition by multicollector inductively coupled plasma mass spectrometry (MC ICP-MS) in different environmental samples (river water, sediments, soils, sand, road dust, mine waste, ores, PM10, PM2.5) was optimized. Special attention was devoted to appropriate sample preparation and Pb isolation from the matrix. The method was then applied to real samples collected in the Upper Meža Valley, while the total concentrations of different PTEs were also determined by ICP-MS. In this way, the local Pb sources were characterized. To investigate the concentration and size distribution of particles carrying Pb and other potentially present PTEs by single particle ICP-MS (spICP-MS), an analytical method for the extraction of nanoparticles (NPs) from PM10 samples was optimized and applied to the PM10 samples collected in the Upper Meža Valley.
The Pb isotope ratios of PM10 samples differed from the local background (soil, sand, mine waste) and approached values of an anthropogenic source present in the area (secondary Pb production). Anthropogenic contributions were estimated to account for (56–69) % of total Pb in PM10. With spICP-MS analyses, both Zn- and Pb-containing NPs in PM10 samples were identified, with (0.6–3.8) % of total Zn and (0.3–1.7) % of total Pb extracted as NPs. This data served as an additional indicator of the Pb sources and, more importantly, as assistance in the estimation of potential health effects of Pb in PM10.