Eva Geršlová

Hydrocarbon-based indicators for characterizing potential sources of coal-derived pollution in the vicinity of the Ostrava City

Coaly material enters various environmental compartments from different emission sources and on diverse pathways. The complexity of both the emission processes and the quality of contamination in the Ostrava region avoids a simple source correlation for coal-derived pollution. Hence, this study focused on the application of different geochemical approaches for source apportionment using bulk parameters, aliphatic biomarkers and source-specific PAH ratios. Major aim was to prove the effectiveness of the applied methods for characterizing the impact of coal-derived contamination in complex emission systems such as in the Ostrava region. Individual emission sources were discriminated sufficiently by TOC vs. TEH relationship and two-dimensional correlations of PAH ratios. Additionally, aliphatic biomarkers revealed individual signatures for all classes of samples and pointed to a widespread distribution of fossil material also in the hydrosphere. On the contrary, indicative PAH ratios documented a dominance of pyrogenic over petrogenic-derived organic matter in the lake sediments investigated. These contradictory descriptions demonstrate clearly that only a comprehensive application of different marker systems allows a detailed view on the quality and quantity of coal-derived pollution. Lastly, it remains unclear whether coaly material in aquatic sediments acts as sink or source for PAHs. A proposed indicative marker, the ratio of phenanthrene over retene, failed.

Mercury contamination of stream sediments in the North Bohemian Coal District (Czech Republic): Mercury speciation and the role of organic matter

Industrial expansion in the North Bohemian Coal District over the past decades has had an adverse effect not only on stream sediments but also on the freshwater system. So far mercury occurrence has not been properly investigated in the area. In response to this situation, the present study applies mercury quantification and speciation in order to predict the possible mobility of mercury. The enrichment factor (EF) and sediment quality guidelines (SQGs) were used to calculate the degree of mercury contamination. An automatic mercury analyser was employed to detect the total mercury content (Hg-T) and Thermal Desorption technique was used to identify mercury species. All the sediment samples were assessed with the contamination degree which increased to very severe in stream sediments in the middle section of the river course. Mercury species identified were chiefly the insoluble forms Hg-FeS2 and HgS. Lignite components and combustion residues were identified as the primary source of Hg contamination in the area.

VYUŽITÍ TERÉNNÍHO RENTGENOFLUORESCENČNÍHO SPEKTROMETRU PRO ANALÝZU ORGANOMINERÁLNÍCH MATRICÍ

The portable X-ray-fluorescence analyzer (Innov-X Systems, Inc.) is routinely used as screening tool in geochemical and environmental mapping. The applicability in organomineral matrices was not tested yet. The biogas is produced from maize silage, grass silage, beef and pig manure and slurry, sewage sludge, organic wastes from food industries, organic household waste. As the main result the digestate (anaerobic digestion residues) is manufactured. The digestate is used as fertilizer and/or fuel. In the presented study the three reference materials and three samples of the digestate were analyzed 50 times each. RFA analytical conditions for reference material and samples: Innov-X Systems, Inc., Delta, time measurement: 1. beam: energy 1–40 kV, time 140 s.; 2. Beam: energy 2–10 kV, time 140 s., analytical mode: geochem2. Statistical evaluation of the data set allowed comparison among accuracy and reproducibility for organomineral matrices. The results are in good correlation with data from standard elemental analyses. The presented results has proved very good or satisfactory reproducibility for fourteen elements (Al, S, K, Ca, Mn, Fe, Cu, Zn, Sr, Zr, Mo, Ag, Pb, Th ). The results for three elements (Al, S, Fe) in digestates have high reproducibility, for the Ag, Mn, Mo, Sr, Zr, Th have good reproducibility. The portable XRF is suitable for the mineral fraction characterization in the agricultural materials such as composts, digestates and silages.