Juan Aguilar with EM contractor Central Plateau Cleanup Company collects a groundwater sample from a monitoring well near the Columbia River. Sampling data has shown a significant reduction in contamination along the river over the past decade.
Juan Aguilar with EM contractor Central Plateau Cleanup Company collects a groundwater sample from a monitoring well near the Columbia River. Sampling data has shown a significant reduction in contamination along the river over the past decade.

RICHLAND, Wash. – While it’s often the Hanford Site’s six advanced pump-and-treat facilities that get the glory — they’re on track to treat more than 2 billion gallons of contaminated groundwater for the seventh straight year — a field sampling group quietly plays a critical role in the success of the sitewide risk-reduction effort.

Each year, field crews with EM Richland Operations Office contractor Central Plateau Cleanup Company (CPCCo) log more than 80,000 miles, collecting up to 25,000 samples of soil and groundwater from hundreds of strategically placed monitoring wells that dot the 580-square-mile Hanford Site.

Detailed data gleaned from analysis of the samples helps gauge the performance of ongoing remediation efforts and supports decision-making to drive efficient, cost-effective groundwater cleanup approaches.

“Groundwater sampling is a key part of our program that doesn’t always get a lot of attention,” said Mike Cline, director of the soil and groundwater division at Hanford. “The quality of information we get from the thousands of collected samples each year is invaluable for evaluating current cleanup methods and planning future remediation efforts.”

A team with EM contractor Central Plateau Cleanup Company prepares to collect groundwater samples from a monitoring well near the center of the 580-square-mile Hanford Site. Each year, field crews log more than 80,000 miles visiting about 2,400 wells and collecting up to 25,000 soil and groundwater samples, which are shipped to a laboratory for analysis.
A team with EM contractor Central Plateau Cleanup Company prepares to collect groundwater samples from a monitoring well near the center of the 580-square-mile Hanford Site.

Sampling results indicate the levels of contaminants in plumes — or areas of groundwater contamination — to help determine the effectiveness of pump-and-treat operations and other cleanup methods. Over the past decade, the results highlight a significant reduction in groundwater contamination along the river, particularly of hexavalent chromium, a toxic chemical used as a corrosion inhibitor in Hanford’s reactors during operations.

Placement of the monitoring wells is also determined using modeling data based on sample analyses. Well location is important for understanding groundwater flow to help manage and reduce the plumes.

“Many of our wells and sampling locations are off the beaten path. Our sampling teams are out in all seasons and weather conditions supporting the groundwater program. It can be tough work,” said Kyle Stiles, supervisor for CPCCo’s field sampling operations. “And not only are our field crews good at what they do, but they also do it safely.”