Magneto Chemical Tracers for Monitoring Hydrothermal and Domestic Wastewater Impacts in Coastal Groundwater Systems

Abstract

Identifying the origin of groundwater contamination in coastal environments remains a critical challenge due to the coexistence of natural hydrothermal discharges and anthropogenic wastewater inputs. This study aimed to evaluate whether magneto chemical tracers the combined use of magnetic susceptibility measurements and geochemical indicators can effectively distinguish between hydrothermal and domestic wastewater influences in coastal aquifers. Groundwater samples were collected from categorized wells representing hydrothermal, wastewater impacted, and background conditions. Field and laboratory analyses were conducted to measure magnetic susceptibility and key chemical and isotopic parameters, including boron, lithium, nitrate, phosphate, and δ¹⁸O/δD isotopes. The dataset was analyzed using statistical comparisons and multivariate clustering to assess tracer performance and source attribution.

The results showed that hydrothermal wells consistently exhibited elevated magnetic susceptibility values alongside enriched boron and lithium concentrations. In contrast, wastewater impacted wells were characterized by high nitrate and phosphate levels but lacked detectable magnetic signals. The integration of magnetic and chemical data improved the resolution of source differentiation, particularly in mixed or transitional wells where chemical profiles alone were ambiguous. These findings demonstrate that magneto chemical tracers provide a novel and effective approach for identifying and distinguishing overlapping sources of groundwater contamination. This method holds significant potential for enhancing water resource monitoring, especially in geologically active coastal regions where timely and accurate source attribution is vital for sustainable aquifer management.