Correlations between on-site screening methods and laboratory analyses of oil-contaminated fuelling station sites

In order to assess the potential of soil contamination from petroleum-based products and determine the soil samples required for laboratory analysis, investigators generally use portable instruments such as photo ionisation detectors (PIDs) or flame ionisation detectors (FIDs) for on-site screening. In this study, PIDs, FIDs, and turbidimetric test kits were integratively used to screen 47 soil samples from 28 fuelling station sites suspected of total petroleum hydrocarbon (TPH) contamination. The PIDs and FIDs achieved high accuracy in screening sites contaminated by gasoline (TPHC6-C9); the test kits yielded high accuracy in screening those contaminated by diesel fuel (TPHC10-C40), as well as high correlation with laboratory analysis. Regression analyses showed high coefficients of determination (R2), reaching up to 0.819 (PIDs versus TPHC6-C9), 0.788 (FIDs versus TPHC6-C9), and 0.653 (test kits versus TPHC10-C40). The integration of PIDs, FIDs, and test kits with laboratory analysis can significantly increase the efficiency and accuracy of soil contamination investigations. We suggest that the application of turbidimetric test kits to screen potential oil-contaminated fuelling station sites can produce accurate assessment results.