Geothermal Water and PFAS Contamination
Geothermal water sources—used for spa applications, direct heating, and aquifer recharge—can contain PFAS from atmospheric deposition, irrigation recharge, or proximity to contamination sources. Understanding PFAS behavior in high-temperature geothermal applications is a specialized but relevant water quality consideration.
Temperature Effects on PFAS Mobility
Elevated water temperatures (>40°C) reduce PFAS sorption to soil and aquifer matrix, increasing dissolved PFAS concentrations in hot groundwater compared to the same aquifer at ambient temperatures. Geothermal systems circulating water through PFAS-contaminated aquifer zones may produce higher PFAS dissolved loads than cold groundwater from the same geological formation.
Spa and Therapeutic Application Risks
Therapeutic hot spring and spa facilities using geothermal water in PFAS-affected regions face dermal and inhalation PFAS exposure concerns. Elevated water temperature increases skin permeability, and hot spring steam creates PFAS aerosol inhalation pathways. Users of geothermal spa facilities in PFAS-contaminated areas warrant exposure assessment.
Treatment for Geothermal PFAS
PFAS removal from geothermal water is complicated by temperature—GAC performance degrades at elevated temperatures compared to ambient water (reversing the cold-water benefit). Treatment systems for geothermal water requiring PFAS removal should incorporate cooling upstream of adsorption treatment or use thermal-resistant ion exchange systems better suited to elevated temperature operation than standard GAC media