Migration characteristics of the chromium contamination field and data inversion results of different detection arrays

To ascertain the contamination range and degree caused by the migration of the chromium contamination field, this study constructed a net reserve-based model for chromium contamination sources in water-rich soils of a permeable layer with high permeability coefficients. Based on the COMSOL software, the migration patterns of the heavy metal contaminant—chromium over time were numerically simulated. Targeting the migration model of the chromium contamination field in different periods, the Wenner, dipole-dipole, and pole-dipole arrays were used for detection, respectively. Through multi-constraint joint inversion of resistivity and polarizability, this study comparatively analyzed the resistivity and polarization imaging effects of different detection arrays. The inversion results show that under noise-free voltage conditions, the detection depths of these detection arrays decreased in the order of pole-dipole, dipole-dipole, and Wenner arrays. The Wenner array yielded better resistivity imaging effects relative to polarization imaging. The dipole-dipole array is suitable for detecting the shallow, small-scale contamination field featuring a complex morphology. The pole-dipole array outperformed others in shallow detection. With a mean disturbance voltage of 7 mV applied, the anti-noise performance of the detection arrays showed descending order of Wenner, dipole-dipole, and pole-dipole arrays, with the apparent polarizability consistently affected less than the apparent resistivity.