Ground-penetrating radar (GPR) responses for sub-surface salt contamination and solid waste: modeling and controlled...

Area of Science:

• Environmental Geophysics
• Geophysical Surveying
• Pollution Monitoring

Background:

• Assessing polluted areas and municipal solid waste (MSW) sites requires efficient, non-destructive methods.
• Current investigation techniques for MSW dumpsites are often destructive, time-consuming, and provide limited data.

Purpose of the Study:

• To evaluate ground-penetrating radar (GPR) wave responses to varying electrical conductivity (EC) in groundwater.
• To assess MSW stratification using a controlled lysimeter and modeling approach.

Main Methods:

• GPR wave simulations were performed using GprMax2D software.
• Field tests were conducted on sand and MSW-filled lysimeters using a Pulse EKKO-Pro GPR system (200 and 500 MHz).
• GPR-reflected wave amplitudes were analyzed under different injected EC levels.

Main Results:

• GPR signal strength decreased with increasing EC; reflections vanished at EC > 0.28 S/m.
• At high EC, plume thickness had minimal impact on reflected wave amplitude, but signal decreased with thickness at constant EC.
• 2D GPR profiles revealed waste layer stratification under wet conditions, but not dry.

Conclusions:

• GPR is a viable non-destructive method for identifying inorganic groundwater contamination and MSW stratification.
• The method offers a larger sample volume compared to traditional point-scale measurements.
• Further research is needed for heterogeneous aquifers and complex dumpsite conditions.