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The aim of the study was to evaluate the content, occurrence, and leachability of arsenic (As), lead (Pb), and thallium (Tl) in wastes from coal cleaning processes with respect to the safe management of this waste. The study focused on wastes resulting from the wet gravitation and flotation processes employed for the purposes of coking coal cleaning in four coal mines situated in the Upper Silesian Coal Basin (Poland). The scope of the study included (i) determination of the content of these elements in the investigated wastes using atomic absorption spectrometry, (ii) evaluation of their mode of occurrence using electron microprobe analysis, and (iii) preliminary assessment of their leachability in deionized water. The content of the analyzed elements in the examined samples of coal waste was twice as high as the average content of these elements in the Earth's crust. The contents of As and Pb, however, did not exceed their permissible contents in inert waste in accordance with Polish legal regulations based on EU directives. The limit on the content of Tl is not specified by these regulations, but its amount in the examined samples was similar to that occurring in the soils. Moreover, leaching tests have shown that these elements are hardly eluted from the analyzed material. Their content in the water leachates was generally lower than the detection limit of the analytical method, complying with the standards for good and very good water quality. Low leachability of these elements most probably results from their mode of occurrence in the investigated wastes. The chemical analysis using an electron microprobe and the analysis of the correlation between these elements, e.g., total and pyritic sulfur, have shown that Pb, As, and Tl are mainly found in sulfide minerals which are characterized by negligible solubility. In conclusion, the investigated hard coal processing waste does not constitute a threat to the environment and can be commercially used or safely neutralized, e.g., by landfilling.

Grain products and the associated industry have a notable economic and social impact all over the world. The toxicological safety of grain products is a nutritional prerogative. This study focused on the determination of thallium content in grain product samples collected from a commercial brand commonly available in Poland. The samples were analyzed with the use of differential pulse anodic stripping voltammetry (DPASV) with graphene oxide based on glassy carbon. The stripping anodic peak current of thallium was linear over its concentration range from 9.78 × 10 -9 to 97.8 × 10 -9 M. The limit of detection (LOD) was calculated according to the formula LOD = (κ × SDa)/b, where κ is 3.3, SDa is the standard deviation of the intercept, and b is the slope. The determined value of LOD was 1.229 µg L -1 (6.01 × 10 -9 M). The proposed method was successfully applied for the determination of thallium ions in samples of actual grain products. The obtained results confirmed that thallium was present in the studied cereal samples (average content at 0.0268 ± 0.0798 mg/kg). Thallium has a half-life of 60 days; therefore, the consumption of foods with thallium content of approximately 0.08 mg/kg has the potential for harmful bioaccumulation in the body. Thallium contamination in cereal products should be a critical parameter for health environmental regulations., Competing Interests: The authors declare no conflict of interest.

Two soils formed on the floodplain terrace of a rivulet flowing through the zinc-lead ore exploration area polluted with thallium and one soil from a floodplain terrace of the reference area were investigated in terms of thallium distribution between soil fractions. Such type of soil is formed on river floodplain terraces next to the main river channel and its composition records the history of river pollution. A sequential extraction of soil according to the BCR protocol was performed with an additional initial stage of extraction with water. Apart from labile thallium, thallium entrapped in the residual parent matter was also determined. Thallium was determined by flow-injection differential-pulse anodic stripping voltammetry. In all three cases, the major fraction is thallium entrapped in parent matter. Top soil from the polluted area contains 49.3% thallium entrapped in the residual parent matter, the bottom soil contains 41% while the reference soil contains 80% in this fraction. The major part of labile thallium is located in the reducible fraction (27.7% of total thallium in the top soil, 27% in the bottom soil and 12.4% of the reference soil). Second in terms of significance is the fraction of oxidizable thallium. The top soil contains 12% of total thallium concentration, the bottom soil contains 19% of total concentration, while the reference soil contains 4.1% of total concentration. The acid soluble/exchangeable fraction of thallium has almost the same significance as the oxidizable fraction. The top soil contains 10.4% of the total concentration, while the bottom soil contains 12% of the total concentration. Water soluble thallium concentration is very small. Comparison of the top and the bottom soil show that thallium has not been transported from the river channel onto the floodplain terrace over a long period.

Thallium is a highly toxic metal that plays no role in the metabolism of plants or animals. Recent studies using small mammals and bird feathers as bioindicators demonstrated for the first time that animals from the vicinity of the Bolesław metal works near Olkusz (southern Poland) had large amounts of thallium in their tissues. Because of concern over these reports, four plant species (Plantago lanceolata, Biscutella laevigata, Dianthus carthusianorum, Silene vulgaris) growing wildly in the same area on a 100-year-old calamine waste heap, as well as the waste heap soil, were examined. The average concentration of thallium in the waste heap soil was 43 mgTl/kg dry wt, with the highest value 78 mg Tl/kg dry wt. P. lanceolata accumulated extremely large amounts of thallium (average, 65 mg Tl/kg dry wt; maximum 321 mg Tl/kg dry wt in roots). S. vulgaris and D. carthusianorum accumulated much less (averages, 10 and 6.5 mg Tl/kg dry wt, respectively). On the other hand, B. leavigata accumulated negligible amounts of thallium in its tissues. The concentration of thallium in plants (shoots, roots) from the calamine waste heap was 100-1000 times the level normally found in plants (0.05 mg Tl/kg dry wt). Possible sources of thallium are discussed and the urgent need for large-scale studies on thallium contamination of soils and vegetation in Poland, especially its southern regions, which are the most industrialized, is pointed out., (Copyright 2003 Elsevier Inc.)

In this investigation thallium contents in soil and plants in the EuroRegion Neisse were analysed and the distribution determined. The median top-soil content is 0.5 mg/kg in the area investigated. In this low-contaminated area the moss Pleurozium schreberi contains 0.04-0.13 microg/g and the moss Polytrichumformosum between 0.01 and 0.05 microg/g Tl. The effects of thallium on man and the terrestrial environment were examined. In an epidemiological study a significant positive correlation was found between the thallium content of the two mosses and the incidence of diseases of the circulatory system. The LOEC for thallium in bioassays with terrestrial invertebrates and plants in artificial soil ranged from 1 to 500 mg/kg, which indicates an toxicity of thallium up to 100 times higher than that of Cadmium.

Studies were carried out in the vicinity of a zinc smelter in southern Poland, 50 km northwest of Krakow, where the previous measurements with another bioindication method revealed huge thallium levels in the environment. The mammals (106 individuals in total) were captured in four wooded areas situated 1.5 to 2.5 km in various directions from the plant and in two reference sites, located far from industrial emission sources. Very high Tl levels were found in livers and kidneys of all mammals examined from the two areas nearest the smelter. Bank voles were the most loaded (maximum Tl in kidneys, 34.27 microgram/g dry mass; in livers, 14.53 microgram/g; values from unpolluted areas were below the detection limit, 0.07 microgram/g). A distinct decrease in the amount of hair-a characteristic of thallium poisoning-was observed in several individuals. The extreme case was a wood mouse with the rear half of its body almost entirely hairless (!). Densities of single populations and the whole community were very low, up to 4.8 individuals/ha, including insectivores. Numerical proportions between species were changed in comparison to unpolluted areas. The age structure was deformed, with a disproportionate small participation by young generations. Among the males studied, only sexually inactive individuals were found. The condition of populations and the community of small mammals living here was much worse compared with data from the surroundings of other zinc smelters., (Copyright 1998 Academic Press.)