Developing contaminated sites has always been a problem. Where is the contamination? Where did it come from? Where is it going? What type of remediation if any, is best suited to the site? With all of these questions the problem of detection is at the heart of them all. Lankelma CPT Ltd recently used a new technology in cone testing for detection of contamination, see Photo 1. 

The Hydrocarbon Cone detects the presence of fuels like petrol, etc. (LNAPL) contamination using a UV light. The UV beam shines out of a sapphire crystal window in the side of the cone. When the UV light comes into contact with a LNAPL contaminant it excites the molecules giving of a florescence. This is detected through the sapphire glass window and its intensity is recorded, see Photo 2.

The hydrocarbon cone is used in the same way as conventional CPT's. This makes it a quick and easy tool to find contamination. It can be used to map out whole plumes finding its thickness, lateral extent and possibly it flow direction in a relatively short period of time. And because the results are instantaneous on site the investigation can be modified as it is carried out depending on what is found.

When used in conjunction with a normal CPT you will get both contamination and geotechnical information about a site. Also because of the size of the cone and speed of the test, the possibility of contaminating other strata from cross contamination is greatly reduced, before grouting the hole back up.