EPA Detects Radioactive Contamination in Groundwater Near St. Louis Landfill

U.S. Environmental Protection Agency (EPA) workers cleaning up the West Lake landfill in St. Louis County have detected contamination in nearby groundwater, prompting the EPA to investigate whether radium may have migrated from the site, the Missouri Independent reported.

St. Louis was part of a geographically dispersed national effort to build the nuclear bomb. Much of the work in the area was on uranium, where Mallinckrodt Chemical Co. was a major processor of uranium concentrate near downtown St. Louis. In 1946, the government purchased land near the airport and began shipping nuclear waste there from the Mallinckrodt facility. Mallinckrodt stored barrels of K-65, a radioactive waste, at the St. Louis airport in deteriorated steel drums.

In 1966, the Atomic Energy Commission (AEC) demolished and buried buildings at the St. Louis airport site. Continental Mining & Milling Co moved the waste to nearby Bridgeton. Radioactive barrels lay outside the fence. The storage was so haphazard that even the road leading to the site was contaminated by trucks that scattered waste as they drove from 1966 to 1969. At this site, uranium processing company Cotter Corp dried the waste and shipped it to its Colorado facility. The site remained contaminated for decades. In 1973, Cotter Corp collected hazardous barium sulfate and dumped it illegally at the West Lake Landfill, also in Bridgeton. The material contained uranium tailings.

Both the St. Louis and Bridgeton airport sites border Coldwater Creek, which runs through the heart of what are now bustling suburban neighborhoods. Tons of trash flowed into Coldwater Creek, contaminating the often-flooded stream and adjacent yards for 14 miles, federal and state investigators determined.

In the late 1970s, the Nuclear Regulatory Commission (NRC), which replaced the AEC, flew a helicopter over the West Lake landfill. The test correctly identified two contaminated areas, but missed large areas of the landfill. Despite warnings from the Missouri Department of Natural Resources and activists that the contamination was likely more widespread, the NRC's conclusion stood for more than 40 years. However, in 2023, the EPA announced that the contamination at the site was more widespread than previously thought.

In a periodic update to nearby communities in May, the EPA said it would add groundwater monitoring wells around the site, which is in Bridgeton, about a mile from the banks of the Missouri River. The expansion, which came after contamination was detected at the edge of the landfill, will help determine whether contamination can migrate from the site and whether it could reach the river. Radium has been detected near the site at a concentration slightly above drinking water limits, the EPA said in a statement, but radium also occurs naturally in rock formations and aquifers.

Originally, the EPA had expected all the necessary groundwater wells to be installed by August 2022, West Lake Groundwater Remediation Project Manager Snehal Bhagat said at a December 2023 briefing. “But the offsite detections required a significant expansion of the network to delineate exactly where the impacts are, so many more wells were installed. We’re still installing them as we continue to narrow the impact boundaries,” he noted.

“At this time, no conclusions have been made about the source(s) of radium in off-site groundwater as data collection is ongoing,” Kellen Ashford, a spokesperson for the EPA’s regional office, said in an email to the Missouri Independent.

Dawn Chapman, co-founder of Just Moms STL, a nonprofit created to support communities near contaminated sites around St. Louis, said she was concerned that the EPA has yet to identify the boundaries of the contamination. Given the radioactive waste and other chemical contaminants in the landfill, she fears it could be a “plume of hellish violence.”

She noted that the parties responsible for the site — the landfill owner, the company that dumped the waste and the U.S. Department of Energy — are nearing the end of the planning process for cleaning up West Lake. “I would have really hoped by now that they would have figured it out,” she said.