Présentations Colloques

Oral Presentation
8.08
Session 8.08: Mineral and Thermal water: an indicator of deep processes and source of economically valuable minerals
Jòzsef Fekete
Origin and maturation of organic matter in thermal waters
The aims of the present study were to find the origin of the possibly toxic and or carcinogen aromatic compounds (e. g. benzene, phenols, polycyclic aromatic hdyrocarbons) present in high concentrations in cca. the half of the hundreds of thermal waters (TWs) studied from two sub-basins of the Pannonian Basin, elucidate their distribution and understand the interaction between kerogen, bicarbonate, carbon-dioxide and hydrocarbon gases during maturation.**Water phase pyrolysis (aquathermolysis) experiments were carried out on different precursor candidates (humic and fulvic acid, bitumen, lignite) to model the generation of aromatic compounds in water. The results of the experiments were compared with the interpretation of the data (isotopic composition, major elements, dissolved aromatics and gases) of ~40 TWs.**Appearance of aromatic products in the TWs requires a threshold temperature of 70-80°C. The major maturity-dependent aromatic compounds are phenol, benzene and naphthalene homologues. Maturation generates carbon dioxide, which significantly affects the major element (sodium, potassium and bicarbonate) concentrations, and hydrocarbon gases are also produced.**The concentrations of benzene to alkylbenzenes produced by pyrolysis show excellent correlation, but the slope of the trend line is determined by the the type of precursor material. Similarly, the concentrations of benzene to alkylbenzenes show excellent correlation in TWs, but the slope of the trend line is different in the two sub-basins considered separately. These results suggest that the major precursor of the aromatic compounds of TWs originating from a given sub-basin can be assessed. ****This research was supported by the European Union and the State of Hungary, co-financed by the European Social Fund in the framework of TÁMOP 4.2.4. A 2-11-1-2012-0001 'National Excellence Program'
Hungary