Jerzy Cabala

Isotopic Tracing of Thallium Contamination in Soils Affected by Emissions from Coal-Fired Power Plants

Here, for the first time, we report the thallium (Tl) isotope record in moderately contaminated soils with contrasting land management (forest and meadow soils), which have been affected by emissions from coal-fired power plants. Our findings clearly demonstrate that Tl of anthropogenic (high-temperature) origin with light isotope composition was deposited onto the studied soils, where heavier Tl (ε(205)Tl ∼ -1) naturally occurs. The results show a positive linear relationship (R(2) = 0.71) between 1/Tl and the isotope record, as determined for all the soils and bedrocks, also indicative of binary Tl mixing between two dominant reservoirs. We also identified significant Tl isotope variations within the products from coal combustion and thermo-desorption experiments with local Tl-rich coal pyrite. Bottom ash exhibited the heaviest Tl isotope composition (ε(205)Tl ∼ 0), followed by fly ash (ε(205)Tl between -2.5 and -2.8) and volatile Tl fractions (ε(205)Tl between -6.2 and -10.3), suggesting partial Tl isotope fractionations. Despite the evident role of soil processes in the isotope redistributions, we demonstrate that Tl contamination can be traced in soils and propose that the isotope data represent a possible tool to aid our understanding of postdepositional Tl dynamics in surface environments for the future.

Thallium isotopes in metallurgical wastes/contaminated soils: a novel tool to trace metal source and behavior

Thallium (Tl) concentration and isotope data have been recorded for contaminated soils and a set of industrial wastes that were produced within different stages of Zn ore mining and metallurgical processing of Zn-rich materials. Despite large differences in Tl levels of the waste materials (1-500mgkg-1), generally small changes in ε205Tl values have been observed. However, isotopically lighter Tl was recorded in fly ash (ε205Tl∼-4.1) than in slag (ε205Tl∼-3.3), implying partial isotope fractionation during material processing. Thallium isotope compositions in the studied soils reflected the Tl contamination (ε205Tl∼-3.8), despite the fact that the major pollution period ended more than 30 years ago. Therefore, we assume that former industrial Tl inputs into soils, if significant, can potentially be traced using the isotope tracing method. We also suggest that the isotope redistributions occurred in some soil (subsurface) horizons, with Tl being isotopically heavier than the pollution source, due to specific sorption and/or precipitation processes, which complicates the discrimination of primary Tl. Thallium isotope analysis proved to be a promising tool to aid our understanding of Tl behavior within the smelting process, as well as its post-depositional dynamics in the environmental systems (soils).

Role of Soil Algae on the Initial Stages of Soil Formation in Sandy Polluted Areas

Abstract Research to evaluate the role of the soil algae in the initiation of pedogenesis in sandy areas and to establish the mineral, chemical and organic composition of soil-algal crusts was done. The investigations area is located in southern Poland in a landscape of drift sand (Bledowska Desert) formed as a result of medieval deforestation related to Ag, Pb and Fe mining activities. Fifteen species of algae (Cyanophyta, Chlorophyta and Heterokontophyta) were identified. In the soil-algal crusts, Corg contents ranged from 0.35-2.23%, Pavail from 9-34 mg · kg−1 and Nt was variable. In investigated area the ground on which soil algae developed was acidic (pH 4.4-5.7 in KCl). Among mineral components in the crust, phases rich in Fe and K dominated (776.5(±2.3) - 2803(±31) mg · kg−1 and 230.5(±3.7) - 696(±22) mg · kg−1, respectively) and elevated concentrations of Zn, Mn and Pb occurred. Soil-crust organic matter includes aliphatic and aromatic compounds, carbohydrate derivatives, phenols, furan and pyrene structures. N compounds have significant contribution in composition of soil-algal crusts - the algae are main source of organic matter in this stage of soil formation. It could accelerate the regeneration of disturbed ecological systems.