No abstract

Fractured rock bodies are especially important in Hungary, where numerous hydrocarbon reservoirs and geothermal fields occur in the fractured crystalline basement of the Pannonian Basin. To simulate a 3D fracture network for both near well regions and at reservoir scale, a fractal geometry based DFN (discrete fracture network) modelling system (RepSim) was used. To perform numerical simulation of the geological-hydrogeological problem, in which the hydraulic interaction is investigated between porous and fractured rock bodies, a finite element modelling system called FeFlow was applied. Modelling results suggest that the protruding basement highs govern heat transfer and fluid flow like a "hydro-geothermal chimney" owing to their stratigraphic and structural position as well as favourable hydraulic and thermal conductivities. Thus such fractured basement highs are deemed prospective for further geothermal investigations.

This study was performed to elucidate the distribution, concentration trend and possible source of polycyclic aromatic hydrocarbons (PAHs) in surface water and bed sediments of the Hungarian upper section of the Danube River and the Moson Danube branch. A total of 217 samples (water and sediments) were collected from four different sampling sites in the period of 2001-2010 and analysed for the 16 priority US Environmental Protection Agency PAHs. Concentrations of total 16 PAHs (∑PAHs) in water samples ranged from 25 to 1,208 ng/L, which were predominated by two- and three-ring PAHs. The ∑PAH concentrations in sediments ranged from 8.3 to 1,202.5 ng/g dry weight. Four-ring PAHs including fluoranthene and pyrene were the dominant species in sediment samples. A selected number of concentration ratios of specific PAH compounds were calculated to evaluate the possible sources of PAH contamination. The ratios reflected a pattern of pyrogenic input as a major source of PAHs. The levels of PAHs determined were compared with other sections of the Danube and other regions of the world.

The objective of this study was to investigate the concentration level and distribution of polycyclic aromatic hydrocarbons (PAHs) in surface water of the Raba River; the largest Danube tributary in Hungary. A total of 54 water samples were collected in the period of 2008-2011 and analysed for PAHs by gas chromatography-mass spectrometry (GC/MS) method. The total PAH concentrations (sum of the concentrations of 17 individual PAH compounds) ranged from 41 to 437 ng/L with the mean value of 111 ±  69.4 ng/L. Phenanthrene and naphthalene were the dominant species in the surface water. Using TEF approaches on the mean concentration PAH data, benzo[a]pyrene and dibenz[ah]anthracene contributed the highest carcinogenic exposure equivalent. A selected number of concentration ratios of specific PAH compounds were calculated to evaluate the possible sources of PAH contamination. The ratios reflected a pattern of pyrogenic input as a major source of PAHs. The comparison of the total PAH concentrations observed for Raba River with other surface waters of the world confirmed that the Raba River could not be regarded as a contaminated river according to the levels of PAHs.