Multielemental composition and arsenic speciation in low rank coal from the Velenje Basin, Slovenia

The effect of geochemical processes on groundwater in the Velenje coal basin, Slovenia: insights from mineralogy, trace elements and isotopes signatures

“…Biodegradation of organic matter in the Velenje basin is also related to the unexpected organoarsenic compounds found in gelified detrital lignite [46,76,77]. Concentrations of arsenic in uncontaminated soils range from 0.2 to 40 mg/kg [78], and the levels in Velenje lignite samples fall within the same range [43,76]. (Table 2) in groundwater from dewatering wells in the Triassic aquifer.…”

Multielemental composition of some Slovenian coals determined with k0 -INAA method and comparison with ICP-MS method

“…Among the major elements, Ca prevails. Major oxides (CaO, Na 2 O, K 2 O, TiO 2 ) and ultimate analysis (LOI, TOT C, TOT S) of the coal samples (13-2123, 13-2125, 13-2130, 13-2134, 13-2138, 13-2141, 13-2145, 13-2157, 13-2162) range as follows (Table 3 a): CaO from 1.91-5.21 %, Na 2 O ranges from 0.04 to 0.13 %, K 2 O ranges from 0.007-0.08 %, TiO 2 ranges from 0.07 to 0.08 %, TOT C ranges from 50.6 to 57.1 %, TOT S ranges from 1.17 to 2.46 %, and LOI (Loss on ignition) ranges from 86.7 to 97.1 % (Kanduč et al, 2019a). Figure 3 represents the major oxides (MgO+CaO, Na 2 O+K 2 O, SiO 2 +Al 2 O 3 +Fe 2 O 3 ) present in samples of lignite.…”

“…Tables 1 and 2 give the results of the k 0 -INAA of 34 elements (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Tb, Th, U, Yb, Zn) for Velenje, Senovo, and Kanižarica mines and for an imported Indonesian coal. In a previous study by Kanduč et al (2019a) (Kanduč et al, 2019a), along the following toxicologically and environmentally relevant elements: As, Ba, Ce, Co, Cs, Cu, Dy, Er, Eu, Gd, Hf, La, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Se, Sm, Sr, Tb, Th, U, V, Y, Zn, Zr were measured in the organic-rich component of the Velenje samples. In this study, nine samples from the Velenje coal mine (13-2123, 13-2125, 13-2130, 13-2134, 13-2138, 13-2141, 13-2145, 13-2157, 13-2162), were measured using ICP-MS and k 0 -INAA, while all other samples in this study were measured using only k 0 -INAA.…”

“…All three of the Velenje lithotypes reflect the composition of the original plant material in the paleomire (Markič & Sachsenhofer, 1997). Arsenic speciation studies and the different forms of calcite present in the coal suggest that bacterial activity was a significant factor during sedimentation of the basin (Kanduč & Šlejkovec, 2005;Kanduč et al, 2018;Kanduč et al, 2019a). The analysis of other geological matrixes such as coalbed gas (Kanduč & Pezdič, 2005;Kanduč et al, 2012, Sedlar et al, 2014 and groundwater (Kanduč et al, 2014;Kanduč et al, 2019b) reveal more evidence of bacterial activity during sedimentation of the basin.…”

“…In the study of Kanduč et al (2019a) organic and inorganic coal samples from -50/C excavation field of Velenje basin were measured using ICP-MS and revealed that the concentrations of the majority of the analysed elements were either equal to or below the global average for coal. Exceptions were Mo (7.76 ± 4.76 µg/g, 3.5 times higher) and U (5.24 ± 3.23 µg/g, 1.8 times higher) in organic-rich samples.…”