Argonne Soil Testing Technology Cleans Contaminated Sites ASAP

Oil and gas producers may save millions of dollars in cleaning soils contaminated with naturally occurring radioactive materials thanks to an on-site soil sampling and testing method developed by Argonne. Pumping oil and natural gas from underground reservoirs brings small quantities of radium to the surface. Over time, this radium—usually radium-226 and to a lesser extent, radium-228—can concentrate in pipe scale and sludge deposits, which in turn contaminates soil and equipment. The traditional approach to cleaning such sites involves complicated soil sampling techniques and shipping these samples to off-site laboratories for analysis—a costly and time-consuming process.

Argonne developed and demonstrated its Adaptive Sampling and Analysis Program (ASAP), which can dramatically cut the time and money needed to characterize—determine exactly what is in the soil—and clean sites contaminated by naturally occurring radioactive materials. ASAP combines real-time data collection with in-field decision-making for faster and more precise site characterization. It was first used at Department of Energy sites.

The demonstration was conducted on a 3.5-acre contaminated site at Lease Management, Inc. in Mt. Pleasant, Mich. Pipes salvaged from nearby oil- and gas-production sites were stored there for cleaning and reconditioning. Contaminated scale from the pipes had fallen off in handling or exposure to the elements, causing varying levels of radium-226 concentrations across the pipe yard.

First, scientists mapped radioactivity on the ground by walking over the site with a portable global positioning system and a hand-held gamma ray detector. Then, using a commercial technology called the RadInSoil™ meter, they determined the relationship between overall radioactivity measurements and radium-226 concentrations. State guidelines are based on these radioactivity concentrations.

Armed with field data, researchers then used Argonne-developed techniques to determine where soil exceeded regulatory standards and would need to be excavated for disposal. To confirm the presence of radium-226, they used a tripod-mounted, camera-like spectroscope to directly measure radium-226 concentrations in surface soils. Using ASAP, it took four days to determine the level of radioactivity in the soil and make decisions on what areas needed to be excavated.

Since soil disposal costs range from about $100 to $200 per cubic yard, limiting soil excavation is important. “The goal is to be as precise as possible in digging up dirt for disposal so you don’t take anything clean with you or leave behind anything above clean-up standards,” said Argonne researcher Bob Johnson.

For sites contaminated with naturally occurring radioactive materials, researchers estimate that using ASAP costs only 10 percent as much as a more traditional char-acterization. In the Michigan demonstration, Johnson expects ASAP to save the site owner at least $36,000 in disposal costs. Johnson says this technology is easily transferred to industry. Plans are underway to host a series of workshops to train members of the oil and gas industry in ASAP techniques.

For more information please contact Donna Jones Pelkie at 630-252-5501

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