Synthetic DNA fragments as high-resolution tracers for hydrological parameter inversion

Accurate estimation of hydrogeological parameters is essential for groundwater modeling but largely depends on the quality of tracer data. Traditional tracers, including dyes and ions, are constrained by signal interference, a narrow selection of options, and poor detection sensitivity. This study investigated synthetic DNA fragments as high-resolution tracers in replicated two-dimensional sandbox experiments. Eight uniquely sequenced DNA tracers were co-injected with dye tracers and assessed using two frameworks: tracer travel-time inversion (TTTI) and a two-step approach combining TTTI with hydraulic tomography. DNA tracers produced clearer breakthrough signals and achieved consistently higher accuracy (R² values of 0.75and 0.75 for twice TTTI; 0.79and 0.76 for twice two-step approach), whereas dye tracers yielded lower and more variable R² values (0.64and 0.59; 0.75and 0.56). These findings demonstrate that DNA tracers, with high specificityand sensitive detection, enable a robust pathway for improving hydrological parameter inversion.

水文地质参数的准确估计是地下水建模的核心环节，但其精度很大程度上依赖于示踪剂数据的质量。传统示踪剂（包括染料和离子）受限于信号干扰、可选范围狭窄及检测灵敏度低等问题。本研究在重复的二维砂箱实验中，探究了合成DNA片段作为高分辨率示踪剂的应用。八种序列唯一的DNA示踪剂与染料示踪剂共同注入，并通过两种框架进行评估：示踪剂旅行时间反演（TTTI），以及将TTTI与水力层析成像相结合的两步法。DNA示踪剂产生了更清晰的突破信号，并持续获得更高的精度（两次TTTI反演的R²值均为0.75；两次两步法的R²值分别为0.79和0.76），而染料示踪剂的R²值更低且波动更大（分别为0.64与0.59；0.75与0.56）。这些发现表明，具有高特异性和灵敏检测特性的DNA示踪剂，为提升水文参数反演精度提供了一条可靠途径。