OIP probe sheds light on contamination and soil structure

The Optical Image Profiler is the latest High Resolution Site Characterisation tool. With an OIP probe we can quickly and efficiently map out the presence of NAPLs in the soil, such as fuels, oil, creosote and tar.

During the investigation with our Geoprobe or CPT rig, we insert the probe into the subsurface and create a depth profile of the NAPLs’ UV fluorescence. For the analysis of dense NAPLs (creosote or tar) we can also make use of the probe equipped with a green LED (OIP-G). This allows us to obtain even better results.

During the investigation, the camera takes a picture every 15 mm.  A green LED or UV behind a sapphire window  induces fluorescence from PAH’s in fuels or oils present in the soil. These images are analysed using acquisition software in order to display the degree of fluorescence in the depth profile. From experience we know that depending on the composition of the NAPLs, the fluorescence can appear in different colours. This is something that does not come to light when standard acquisition methods are used. With more elaborate data processing, our experienced specialists can display this information more clearly in fluorescence profiles.

Additional images under visible LED light and additional sensors in the OIP probe (EC, HPT, CPT) then provide insight into the soil structure and how the contamination is spreading within it.