Determination of Some Heavy Metals in European and Polish Coal Samples.

This work presents coal analyses for heavy metal content (Tl, Cu, Zn, Cd, Fe). The tested coal samples came from a Russian deposit in the Kuzbass Basin (Novosibirsk and Kemerovo Oblasts, near Kazakhstan) and from Poland. The concentration of thallium in coal was determined using DPASV-differential pulse anodic stripping voltammetry-and other metals were examined with FAAS, i.e., flame atomic absorption spectrometry. The study confirmed the presence of thallium in the tested coal sample. The coal samples from outside the European Union contained four times more thallium (the maximum content of thallium in coal has been determined to be 0.636 mg·kg-1) than the samples of Polish coal (where the maximum content of thallium was 0.055 mg·kg-1). Cadmium concentration was on average 1.99 mg·kg-1 in the samples from outside the European Union, and 1.2 mg·kg-1 in the samples of Polish coal. Zinc concentration in the samples from outside the European Union was on average 11.27 mg·kg-1, and in the samples of Polish coal approx. 7 mg·kg-1. In addition, iron concentration in all coal samples was determined as 14.96 mg·kg-1, whereas copper concentration in the samples from outside the European Union averaged as 3.96 mg·kg-1. The obtained results do not show any correlation between the presence of thallium and the presence of other metals. It is worth noting that heavy metals pose a threat to living organisms due to their persistence and bioaccumulation, particularly in the context of dust emissions to the atmosphere.

Speciation and mobility of volatile heavy metals (Cd, Pb, and Tl) in fly ashes.

Speciation of volatile metals Cd, Pb, and Tl in fly ashes (FAs) produced from burning of hard coal in stocker-fired boilers (SFBs) was studied. Two grain fractions of fly ash collected in a multicyclone and battery cyclone of the systems of dust separation from three SFB units operating in various urban heating plants were analyzed. The characteristic feature of speciation of the three metals was a large share of labile fractions: Cd (av. 46.1 %), Pb (av. 39.8 %), and Tl (av. 21.6 %). The fraction which most clearly reflected the different chemical properties of the investigated metals was the oxidizable fraction: F(4)-Cd-0 %, F(4)-Pb-av. 10.0 %, and F(4)-Tl-av. 30.2 %. The importance of condensation of the volatile metal species on FA particles for shaping speciation of these metals was characterized using the normalized enrichment factor (NEF): Pb (2.3 ± 0.8) > Tl (1.8 ± 0.9) ≈ Cd (1.7 ± 0.6). Speciation of heavy metals may also be important economically, because the level of mobility coefficients (K Cd = 0.46, K Pb = 0.40, and K Tl = 0.22) in the case of fly ashes considerably enriched with toxic metals (Cd 4.8 ± 3.4 mg/kg, Pb 293 ± 210 mg/kg, and Tl 6.3 ± 4.5 mg/kg) may limit their utilization range.

Fractionation and Mobility of Thallium in Volcanic Ashes after Eruption of Eyjafjallajökull (2010) in Iceland.

Volcanic ash contains thallium (Tl), which is highly toxic to the biosphere. The aim of this study was to determine the Tl concentration in fractions of volcanic ash samples originating from the Eyjafjallajökull volcano. A sequential extraction scheme allowed for a study of element migration in the environment. Differential pulse anodic stripping voltammetry using a flow measuring system was selected as the analytical method to determine Tl content. The highest average content of Tl in volcanic ash was determined in the fraction entrapped in the aluminosilicate matrix (0.329 µg g(-1)), followed by the oxidizable fraction (0.173 µg g(-1)). The lowest content of Tl was found in the water soluble fraction (0.001 µg g(-1)); however, this fraction is important due to the fact that Tl redistribution among all the fractions occurs through the aqueous phase.

Thallium in fractions of sediments formed during the 2004 tsunami in Thailand.

Thallium is a highly toxic element. Its concentration in sediment fractions from the 2004 tsunami in Thailand was investigated. A modified BCR procedure was used for sequential extraction. Tl was determined by flow injection differential pulse anodic stripping voltammetry. It was found that the majority of thallium in the investigated tsunami sediments (86-97 percent) is entrapped in the alumosilicate parent matter i.e. it is entirely immovable. Only the total destruction of this residual fraction with hydrofluoric acid made this thallium available. The conclusion strongly supports the hypothesis that thallium is mainly entrapped in alumosilicate parent matter. Total thallium concentration in the investigated tsunami sediments was divergent in various samples from 0.37 to 1.13 µg g(-1) and significantly different from the reference area (0.05 µg g(-1)). Tsunami sediment fractions from different sampling points are divergent in terms of total thallium concentration and concentration of mobile thallium. Generally, mobile thallium concentration was growing in sequence: water soluble fraction

Thallium in fractions of soil formed on floodplain terraces.

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.

Biodegradation of oxo-alcohol ethoxylates in the continuous flow activated sludge simulation test.

Biodegradation of two alpha-methyl branched oxo-alcohol ethoxylates (OAE) of different polydispersity: LIAL 125/14 BRD (LIALB) (broad M.W. distribution) and LIAL 125/14 NRD (LIALN) (narrow M.W. distribution), both having an average of 14 oxyethylene subunits (EO) and a C(12-15) alkyl moiety were tested under the continuous flow activated sludge conditions of the classical Husmann plant. Primary biodegradation and concentration of metabolites: free oxo-alcohol fraction (FOA) and poly(ethylene glycols) (PEG), were measured. PEG were divided into two fractions: short-chained PEG (PEGshch) (1-4 EO) and long-chained PEG (PEGlch) (>4 EO). The indirect tensammetric technique combined with an adequate separation was used for analysis. Central fission was found to be a highly dominating pathway, as is the case with fatty alcohol ethoxylates. OAE are highly primarily biodegraded (above 95%). High concentrations of FOA and PEG are formed. Once formed the PEGlch are further fragmented into the PEGshch. Free alcohol fraction compounds are biodegraded sooner when alkyl moiety is shorter. OAE polydispersity has an influence on the kinetics of biodegradation; PEG formed from LIALN are biodegraded slower and to a lower degree than those from LIALB.

Oxidative extraction versus total decomposition of soil in the determination of thallium.

An aqua regia extraction and a total decomposition of soil were compared in terms of thallium determination. A sequential extraction of soil, according to the BCR protocol, was also performed for additional information on thallium distribution in soil fractions. Certified reference material-soil GBW 07401 of Chinese origin, containing 1+/-0.2ppm of thallium was used in these experiments. Thallium was determined by flow injection-differential pulse-anodic stripping voltammetry (FI-DP-ASV). Only 35% of total thallium was extracted in the aqua regia extraction, while the total decomposition led to satisfactory recovery. The sequential extraction showed that only 5% of thallium in GBW 07401 is dissolvable in the four BCR procedure fractions, and that 95% of the element is entrapped in the residual parent matter. These results show that the aqua regia extraction does not ensure complete thallium extraction from soil. Surprisingly, the total decomposition is significantly less time consuming than the aqua regia extraction.

Thallium in soils and stream sediments of a Zn-Pb mining and smelting area.

Thallium was determined in 120 samples of soil and 30 samples of stream sediments from the southeastern part of the Silesian-Cracowian zinc-lead ore deposits. Soil samples were taken from topsoils (0.0-0.2 m) and bottom soils (0.8 and 1.0 m). Thallium was determined by flow-injection-differential-pulse anodic stripping voltammetry. The samples were decomposed sequentially with 73% hydrofluoric acid and a mixture of nitric acid and hydrogen peroxide. The results showed that zinc-lead ore mining as well as their processing and smelting leads to a significant increase of thallium in the top layer of soil and in stream sediments. The highest recorded concentration was 150 ppm Tl for stream sediment and 35 ppm for a soil sample. Thallium concentration in small rivers from the investigated area was by 2 orders of magnitude higher than in the reference area. The highest recorded concentration being 3.24 microg L(-1).