CONICET | Buscador de Institutos y Recursos Humanos

The Caviahue-Copahue geothermal system (Northwest of Neuquén province, Argentina) presents several hydrothermal manifestations in the forms of hot springs, pools and ponds where thermal muds are accumulated. These peloids are a mixture of sulfur and clay-minerals, organic matter and fluids that contain dissolved gases like hydrogen sulfide. Besides, they are inhabited by complex microbial communities, formed by known and novel species, including sulphate reducing microorganisms (SRM). The sulfate-reducing activity in addition to the natural clay-minerals adsorption capacity, give such muds a central role in the biogeochemical processes of the area and suggests they could be used for the retention of heavy metals and metalloids as an alternative for the reduction of the metal load in contaminated effluents. To prove this hypothesis, muds from four sites with different characteristics were collected: Baño-9 (33ºC, pH 5.87), Las Máquinas-I (70ºC, pH 3.23), Las Máquinas-II (76ºC, pH 5.95) and Las Máquinas-III (35.9ºC, pH 1.53). The experiments were carried out in sealed 10 mL vials in anaerobic conditions, to favor the development of SRM, with 2 grams of each mud and 8 mL of sterile metal solution (Cd or Cu at two different pH conditions: 2.4 and 5.9) to reach the concentration of 10 ppm. The vials were stored for 14 days at 15ºC, 30ºC, and 60ºC. Each combination of factors was performed five times for statistics purposes. Samples taken at the beginning and end of the experiment were analyzed for residual metal concentration using atomic absorption spectrophotometry. The results show an important retention of metal ions proving that the Copahue geothermal muds could be an alternative in the remediation of contaminated effluents. Future studies are expected to establish the role of the microbial communities of the different muds as well as to characterize them both genetical and physiologically.

enviar mensaje