Everyone’s looking for technologies that save time and money. We have found that when it comes to delineating soil and groundwater contamination, laser-induced fluorescence and membrane interface probes do both—exceedingly well. Both tools save time by eliminating the need to wait for lab results to determine if further investigation is necessary, which allows important decisions to be made immediately.

Image Courtesy of Columbia Technologies. SmartData Solutions® provides real time, 3D, color, mapping of subsurface contamination detected with LIF and MIP direct sensing technologies.

Until recently, the only way to discover subsurface contamination was to take physical samples for lab analysis—but no longer. Now, sensors provide more and better information on a wide range of volatile organic compounds (VOC) including chlorinated solvents and petroleum hydrocarbons. Additionally, this approach is faster and cheaper than traditional sampling.

Brownfield projects, in particular, can benefit from what these technologies offer. Redevelopment initiatives frequently involve decisions made by multiple individuals with expertise in myriad areas. Therefore, it is imperative that every person in the process understand the entire picture—the specific information as well as the ramifications.

We have found that 3D, color visualizations of the subsurface are highly effective in bridging knowledge and information gaps. Akin to an MRI, the information processing system we offer produces 3D images of the geologic subsurface with details of soil composition, size and volume of contaminant plumes, types of contaminants, locations—and, importantly, where the contamination is not. The beauty of these technologies—direct sensing tools coupled with Smart-Data Solutions® information processing—is real-time information that is actionable.

Additionally, multiple readings are taken 20 times every 12 inches, and at an average depth of 65 feet, yield approximately 1,300 data points for each boring. Verifiable, comprehensive information is integral to successful remediation. And, when used for post-remediation evaluation, these tools provide an added measure of confidence in the safety of the site.

Recently, on a brownfield downtown development site in Idaho, the membrane interface probe (MIP) was used to detect and delineate drycleaning chemical perchlorethylene (perc) and other hazardous compounds in the subsurface. Because the process is quick, half of the downtown area was imaged to 70’ depth within two weeks, causing virtually no disruption to the city.

In the case of the Idaho investigation, for example, the project manager reviewed the data from his off-site office as site data continued to be collected. This was the second time the site was investigated using direct sensing technology. Data collected in 2005 prompted planners to raise the bottom of Indian Creek’s new channel by a few feet to prevent any potential perc contamination of the rerouted waterway. The redeveloper suggested that the data may help the city trace the source of any perc contamination and allow planners to take precautions when designing new buildings.

Case in point: an investigation conducted earlier this year involved a site that hosted a variety of contaminations throughout various layers of clay. Traditional samples would have been very difficult, if not impossible, to collect within this geology. Even if it was achievable, a traditional sampling approach would not have been able to identify the sources of the various contaminations. However, using both LIF and MIP and the higher data density they afford, the sources were clearly and readily identified.

Whether on a barge in deep water, in the desert, inside a building or in an urban setting, these technologies are well suited for the widest variety of environments. Furthermore, they have enabled investigations of sites with complex geologies that until a few years ago would have remained uninvestigated because of prohibitive costs.

John Sohl is CEO of COLUMBIA Technologies