Dense nonaqueous phase liquid tracer tests: experimental results

Area of Science:

• Environmental Science
• Hydrogeology
• Geochemistry

Background:

• Dense nonaqueous phase liquids (DNAPLs) pose significant challenges for groundwater remediation.
• Understanding DNAPL distribution and quantity is crucial for effective site cleanup strategies.

Purpose of the Study:

• To conduct dense nonaqueous phase liquid (DNAPL) tracer tests to assess DNAPL presence and quantity in a shallow aquifer.
• To utilize partitioning and non-partitioning tracers to characterize DNAPL sites.

Main Methods:

• Performed two dense nonaqueous phase liquid (DNAPL) tracer tests using i-Propanol (non-partitioning), n-hexanol, and n-octanol (partitioning).
• Integrated field data, mathematical modeling, column tests, and prior sodium chloride (NaCl) tracer tests for test design.
• Employed mathematical modeling for semi-quantitative estimation of DNAPL volumes.

Main Results:

• Tracer tests indicated the presence of dense nonaqueous phase liquid (DNAPL) at both tested locations.
• Mathematical modeling yielded semi-quantitative estimates of the DNAPL amounts present at the sites.
• Aquifer heterogeneity and complex mass transport effects influenced the interpretation of test results.

Conclusions:

• Dense nonaqueous phase liquid (DNAPL) tracer tests are effective in detecting DNAPL presence in aquifers.
• Mathematical modeling can provide valuable semi-quantitative estimates of DNAPL contamination.
• Site-specific conditions, such as aquifer heterogeneity, must be carefully considered when interpreting DNAPL tracer test data.