Comparative study on humic substances isolated in thermal groundwaters from deep aquifers below 700 m

Copyright © 2012 by The Geochemical Society of Japan. as spectroscopic characteristics was discussed in some studies (Wassenaar et al., 1990; Grøn et al., 1996; Artinger et al., 2000). Thurman (1985) studied several properties of HS isolated from Ca(HCO3)2 and CaSO4-rich groundwater originating from different depths in sandy, dolomitic or limy aquifers. He found that groundwater containing organic carbon concentration greater than 1 mg/L either may originate from aquifers receiving recharge from organic-rich waters or may be in contact with sediments rich in kerogen. However, the investigation of HS from deep groundwater or geothermal water has received relatively little attention compared with other environments (Thurman, 1985). The isolation of humic acid (HA) and fulvic acid (FA) fractions from thermal waters circulating in deep aquifers of the Pannonian Basin has been carried out recently (Kovács et al., 2010). Based on our knowledge, our group was the first who isolated HS from deep thermal waters. However, thermal waters from Pannonian Basin were studied earlier by Sajgó et al. (1998), Kárpáti et al. (1999) and Fekete et al. (2009) that found several aromatic families in hot waters with outflow temperature over 70–80°C. They suggested that the appearance and abundance of aromatic hydrocarbons, alkyphenols and fatty acids in thermal waters is controlComparative study on humic substances isolated in thermal groundwaters from deep aquifers below 700 m