The US Army Corps of Engineers announced last week (Aug. 19) that a residential area in Missouri’s St. Louis County is contaminated with radioactive waste. Significant levels of thorium 230, a radioactive isotope, were discovered in public parks and private yards that have been touched by floodwaters from Coldwater Creek, a tributary of the Missouri River.
According to the St. Louis Post-Dispatch, this “is the first time in more than 15 years of Corps-directed cleanups in the region that the government has confirmed radioactive contamination on residential properties.”
Coldwater Creek crosses through 20 miles of northern St. Louis County, and it’s no secret that the water was contaminated half a century ago when the US was developing its first atomic bomb. The country’s only uranium plant, a Mallinckrodt Chemical Works facility, was in downtown St. Louis. Radioactive waste was shipped to nearby Hazelwood, Missouri, and dumped on open ground—where it made its way into Coldwater Creek. Since then, the creek has flooded several times, spilling water into yards, gardens, and even the basements of nearby homes.
Around 2011, residents in the area began suspecting that their community had turned into a cancer cluster, with higher-than-average rates of cancer and other illnesses due to contamination from the creek. As Al Jazeera reported in series of articles this April, the residential yards and public parks subject to Coldwater Creek flooding had never been tested for radioactive isotopes. Testing at sites directly alongside the creek only began in June of this year, followed by the more recent investigations of contamination in areas subject to the creek’s floods.
The levels of thorium 230 that were discovered last week are from samples dug up 6 to 12 inches (15 to 30 cm) below ground in yards and parks, “in some cases showing levels two to four times the threshold for required cleanup,” according to Al Jazeera. Government officials maintain that there is no immediate health risk to residents, though they say they will initiate cleanup efforts.
More instances of contamination are expected to be found as testing continues near other dump sites in the area, including landfills in Bridgeton, Missouri, where an underground fire is currently smoldering nearby. Concerned residents say that could exacerbate any ongoing fallout.