Identifying Diesel Contamination in Soil

Contamination of soil due to leaks, spills, and seepage is a worldwide problem usually diagnosed by costly and time-consuming methods like wet chemistry. A faster solution to identifying contaminants in soil is to use a UV-VIS-NIR field spectrometer like Spectral Evolution’s oreXpressTM, oreXplorerTM, or oreXpertTM. Whether in the field or the lab, NIR is used to identify hydrocarbon contaminants like diesel in soil by showing key absorption features related to hydrocarbons.

The spectral absorption features of hydrocarbon contaminated soils are apparent around 1647, 1712, and 1759 nm in the first overtone region of the NIR band. The absorption around 1647 nm is attributed to C–H stretching modes of ArCH linked to polycyclic aromatic hydrocarbons. Absorptions around 1712,1759 nm and 2304,2340 nm are attributed to C–H stretching modes of terminal CH3 and saturated CH2 groups linked to total petroleum hydrocarbon, both present in the contaminating diesel fuel.