In situ laser-induced fluorescence (LIF) analysis of petroleum product-contaminated soil samples

General considerations of the calibrations of in situ measurements are presented and the concept of using an "average oil" with average analysability for calibration purposes is introduced. The in situ analysis of 30 petroleum product-contaminated soil samples with laser-induced fluorescence (LIF) spectroscopy was performed. Compared to an uncontaminated laboratory reference (LR) soil, 23 soil samples exhibited significantly higher LIF signals, so that these soil samples were classified as contaminated. The repeatability and reproducibility of the in situ LIF analysis were investigated. For the calibration of the LIF data, two LR oils (a fuel oil and a crude oil) were employed. The degree of soil contamination with petroleum products ranged from the limit of detection (LOD) for LIF analysis (ca. 100 ppm), or below, to more than 10,000 ppm. The petroleum product concentrations determined with in situ LIF analysis reveal a reasonable correlation with the results of standard IR analysis after extraction of the contaminated soils.