| Title | Environmental monitoring of the Theistareykir high-temperature geothermal field: Impacts on Groundwater in Northeast Iceland |
|---|---|
| Authors | Deirdre E. Clark, Finnbogi Óskarsson, Magnus Ólafsson, Heimir Ingimarsson, Ásgerður K |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Sustainable geothermal utilization requires long-term monitoring to protect local water resources. Environmental monitoring at the Theistareykir geothermal power plant (operational from 2017) in Northeast Iceland has been systematically conducted since 2012, tracking groundwater quality and northward groundwater flow towards Öxarfjörður through Kelduhverfi. Sampling has involved groundwater boreholes at Theistareykir, including the production well ÞR-09, and cold and tepid springs in Kelduhverfi. Monitoring consistently demonstrates that concentrations of arsenic and aluminium have remained constant and below Icelandic environmental and drinking water standards (≤0.4 µg/L and 200 µg/L, respectively), which are also below thresholds outlined by the EU Water Framework Directive and World Health Organization drinking water guidelines. Similarly, concentrations of copper, zinc, cadmium, lead, chromium, and nickel have consistently been low – typically close to analytical detection limits with minor fluctuations. Stable water isotope analyses (δD and δ18O) confirm that groundwater in the area primarily originates from meteoric sources, with little evidence of evaporation or mixing with geothermal fluids. These long-term monitoring results indicate minimal groundwater impacts from geothermal operations, supporting sustainable geothermal development. The findings align specifically with the UN Sustainable Development Goals SDG 6 (Clean Water and Sanitation) and SDG 7 (Affordable and Clean Energy). |