An Eco-Friendly Dual-Tracer Method Combining Synthetic DNA Fragments and Heat for High-Resolution Characterization of Aquifer Hydraulic Conductivity

Developing environmentally benign, high-resolution subsurface imaging is imperative for sustainable groundwater management. However, traditional tracers (ions, dyes, isotopes) face challenges due to limited variety, low sensitivity, and contamination risks. We present a dual-tracer approach where synthetic DNA fragments (DNA tracers) and heat (thermal tracer) play complementary roles: heat provides priors, while DNA serves as the primary tracer for high-resolution, eco-friendly hydraulic conductivity characterization. This method improved predictive accuracy in hydraulicdrawdown (R2= 0.80, RMSE= 0.95cm, MAE= 0.67 cm), over individual tracers (R2= 0.67-0.75, RMSE= 1.09-1.51cm, MAE= 0.80-1.11cm). Leveraging a biodegradable library, DNA tracers achieved high sensitivity with minimal hazards, significantly outperforming dye tracers, which achieved R2 =0.66(RMSE=1.10 cm, MAE=0.83 cm),when fused with thermal tracers due to narrow variety and low detection sensitivity. This highlights the significance of fusing biological and thermal tracers for precise, sustainable aquifer characterization.