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Monitoring Hanford's groundwater and protecting the Columbia River

During the 45 years of plutonium production at Hanford, waste water was being dumped on or injected into the ground. We oversee the monitoring and cleanup of contaminated water underground, or groundwater, on the Hanford site.

Today at the 580-square-mile Hanford site, the water under 60 square miles is still contaminated beyond safe drinking water limits. We continue to monitor the water and the treatment activities to limit the amount of contamination entering the Columbia River.

Monitoring Hanford's groundwater

Each year about 1,000 wells on and around the site are sampled to determine what types of contamination exist in the ground under the Hanford site, and where the contamination has spread. Some of Hanford's contaminated groundwater enters the Columbia River. Because the river is so large, and typically has hundreds of thousands of gallons of water flowing by every second, the contamination that does enter the river is diluted to barely detectable levels.

Columbia River on a cloudy winter morning.
How was Hanford's groundwater contaminated?

The primary contaminants of concern include uranium, technetium-99, iodine-129, tritium, carbon tetrachloride, hexavalent chromium, and strontium-90. Nitrate contamination is also widespread. While plutonium might be present in a few sites at very low levels, it’s not considered a major contaminant.

Visitors tour the pump-and-treat facility, which cleans up to 3,400 gallons of water per day.

Visitors tour the pump-and-treat facility to see how contaminated water is treated.

Groundwater cleanup facilities

With funds from the American Recovery and Reinvestment Act of 2010, the U.S. Dept. of Energy built a new pump-and-treat facility capable of cleaning about 3,400 gallons a day of contaminated groundwater. Prior to that, smaller pump-and-treat systems were scattered around the site, and most treated less than 200 gallons a day. This new facility has decreased the spread of contamination plumes and decreased the volume of major pollutants.