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Abstract

High contents of arsenic (As) in coal samples from four localities within Neogene deposits of the Pannonian Basin in Slovenia are presented and discussed in this paper. Data from three localities represent interval samples of coal cuttings from wells TER-1 (Terbegovci), Sob-3g (Murska Sobota), and MD-1 (Mislinjska Dobrava). The fourth locality is Globoko, where the main lignite seam was analysed already in 1989. The oldest are coal samples from the MD-1 well which are supposed to be of the Lower Miocene age (except for the shallowest one, which is of the Plio-Quaternary age). Coal samples from the TER-1 and Sob-3g wells are of the Upper Miocene age (Mura Formation). The lignite sample from Globoko is of the Upper Miocene age too (Pontian; Globoko Formation). Most samples were prepared for the ICP-MS method analysis as "whole coal", dry, pulverized lab-samples, weighting ca. 10 g. The results show for all "whole coals" samples considerably increased contents of As: 22.7, 111.4, 222.1, and 131.4 µg/g for the Lower Miocene (?), and 84.5 µg/g for the Plio-Quaternary coals from MD-1 well, 392 µg/g for coals from the Sob-3g well, and 116 µg/g for a coal from the TER-1 well (both Upper Miocene -Mura Formation). In the case of Globoko, not "whole coal" but its high temperature ash was analysed and showed As content as high as 170 µg/g applying AAS method of analysis, and even 260 µg/g applying the ICP-MS. Origin of As could be pre-Neogene rocks of the hinterland and/or Neogene calc-alkaline volcanites. Mineral-gas exhalations from the under-continental upper mantle, containing As, could also be a source of this highly volatile element. IzvlečekV članku predstavljamo in razlagamo rezultate o visoki vsebnosti arzena (As) v vzorcih premoga iz štirih lokalnosti znotraj neogenskih plasti na območju Panonskega bazena v Sloveniji. Podatki iz treh lokalnosti predstavljajo intervalne vzorce drobcev premoga iz vrtin TER-1 (Terbegovci), Sob-3g (Murska Sobota) in MD-1 (Mislinjska Dobrava). Četrta lokalnost je Globoko, kjer je bil glavni lignitni sloj analiziran že leta 1989. Najstarejši premog je iz vrtine MD-1 in je spodnjemiocenske starosti, razen najzgornejšega vzorca, ki je pliokvartarne starosti. Premogi iz vrtin TER-1 in Sob-3g so zgornjemiocenske starosti (Murska formacija). Lignit iz Globokega je tudi zgornjemiocenske starosti, določneje, pontijske (Globoška formacja). Večina vzorcev je bila pripravljena za analizno metodo ICP-MS kot vzorcev »celotnega premoga«. Laboratorijski vzorci so bili suhi, uprašeni in so tehtali okoli 10 g. Rezultati so pokazali za celotne premoge naslednje vsebnosti As: 22,7; 111,4; 222,1 in 131,4 µg/g za spodnjemiocenske premoge in 84,5 µg/g za plio-kvartarni premog iz vrtine MD-1 ter 392 µg/g za premoge iz vrtine Sob-3g in 116 µg/g za premog iz vrtine TER-1. Lignit iz Globokega je bil analiziran kot visokotemperaturni pepel z metodama AAS in ICP. Prva je pokazala vsebnost As 170 µg/g, druga pa 260 µg/g. Izvore As in njegove vezave na organsko/mineralno premoško snov je iskati v pred-neog...