Diffusive gradients in thin films 기반 지하수 모니터링을 통한불포화대 토양 안정화에 따른 중금속 확산 여부 평가

초록

This study evaluated groundwater metal behavior before and after stabilization in a difficult-to-remediate site usingdiffusive gradients in thin films (DGT). Iron salt solutions (FeCl3) and neutralizing agents (NaOH) were sequentiallyinjected into the vadose zone for in situ Fe oxides synthesis, and time-weighted average concentrations (TWAC) of As,Cd, and Zn in the groundwater at four monitoring wells were determined using the DGT to assess the changing patterns ofmetal leaching from the vadose zone into groundwater. To determine whether the average concentration changed afterstabilization, a Welch’s t-test was applied. The results showed that no statistically significant changes were observed for allmetals in all wells, with p-values exceeding 0.05. Also, a segmented regression was applied to detect the change pointsand slope shifts. Most change points occurred before stabilizing agent injection, and those observed after injection showedno significant slope changes. Overall, stabilizing agent injection had no significant effect on groundwater metals, while theDGT-segmented regression approach was useful for detecting gradual dispersion.

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