Capabilities of an optical direct push probe for 2D-subsurface imaging

Area of Science:

• Environmental Science
• Hydrogeology
• Geophysics

Background:

• Characterizing hydrological conditions at polluted sites is crucial for understanding contaminant transport.
• Traditional methods like soil coring and well installation offer limited subsurface insights.
• Direct-push techniques provide high-resolution data but often require specialized tools.

Purpose of the Study:

• To investigate the applicability of the Optical Imaging Profiler (OIP) for groundwater tracing using fluorophores.
• To evaluate the OIP's capability in detecting soil texture and color variations for site characterization.
• To assess the OIP as a multifunctional tool for contaminated site assessment.

Main Methods:

• Laboratory experiments were conducted to test the OIP's ability to detect various fluorophores.
• Field trials involved injecting a fluorophore solution (eosin Y) and monitoring its detection radius.
• The OIP was equipped with a visible light source to capture images of soil texture and color.

Main Results:

• The OIP successfully detected fluorescent contaminants in laboratory settings, with signal strength correlating to fluorophore concentration and pore size.
• A field trial demonstrated clear detection of injected eosin Y within a 0.5m radius.
• Soil color variations detected by the OIP correlated with water saturation and redox processes at a second field site.

Conclusions:

• The OIP is effective for qualitative groundwater tracing using fluorophores.
• The OIP can capture soil texture and color data, serving as a proxy for hydrological and geochemical properties.
• The Optical Imaging Profiler is a versatile, cost-effective tool for characterizing contaminated sites.