Children who lived near a St. Louis creek polluted with radioactive atomic bomb waste from the 1940s through the 1960s were more likely to be diagnosed with cancer over their lifetimes than children who lived farther from the waterway, a new study has found.
The findings, published in JAMA Network Open, corroborate worries that neighbors of Coldwater Creek have long held about the Missouri River tributary where generations of children played.
"We actually saw something quite dramatic, not only elevated risk of cancer, but one that increased steadily in a sort of dose-response manner the closer the childhood residents got to Coldwater Creek," said the study's senior author, Marc Weisskopf, an epidemiology professor at the Harvard T.H. Chan School of Public Health.
As part of the Manhattan Project, Mallinckrodt Chemical Works processed uranium in St. Louis for the development of an atomic bomb. By the mid-1940s, according to historians, the company began to haul its radioactive waste north of the city, leaving it in open steel drums, unattended and exposed to the elements, next to Coldwater Creek.
The study's release comes shortly after passage of the "One Big Beautiful Bill" which contained a little-known provision to help people sickened by exposure to nuclear waste in Missouri and elsewhere. It provides payments of $25,000 to families of people who died as a result of radiation-linked cancers in the St. Louis area and $50,000 to those who developed the cancers and survived.
Like the new study, the provision recognizes the potential health risks from lower radiation levels associated with the production of the atomic bomb. Previous legislation, the Radiation Exposure Compensation Act, known as RECA, expired last year after paying out $2.6 billion to people who developed cancer after exposure to high-dose radiation from participating in onsite atomic weapon testing, mining or hauling uranium or being downwind of the Nevada test site.
Sen. Josh Hawley, a Republican from Missouri, pushed to get a new version of RECA into the Trump budget bill. Hawley had been a vocal critic of the BBB's $900 billion cut to Medicaid, but in the end voted for the massive package of tax and spending cuts. Hawley's yes vote came after a $50 billion fund for rural hospitals was added to the BBB.
Research treasure trove: Decades-old baby teeth
Weisskopf and his research team had the addresses of 4,209 tooth donors from the St. Louis Baby Tooth Survey. Participants, born between 1945 and 1966, donated their baby teeth for science starting in 1958 and joined the new experiment between 2021 and 2024. Weisskopf initially planned to study cognitive decline, but after participants repeatedly mentioned Coldwater Creek, he pivoted to investigating proximity to the creek and cancer risk.
Almost one-quarter of the participants reported having cancer. Those who lived within one kilometer of the creek as children were 44% more likely to report having cancer than those who lived more than 20 kilometers away. Even more striking, those who lived within one kilometer of the creek were 85% more likely to have radiosensitive cancers, cancers believed to be caused by radiation.
Dr. Rebecca Smith-Bindman, a radiologist and epidemiology professor at the University of California, said she was impressed with the design of the study, with which she was not involved. "This study adds to our understanding that radiation is carcinogenic and that we have to be cautious to minimize exposures to radiation wherever possible," she said. The main source of exposure today comes from medical imaging, she said.
The study also highlights the need to clean up areas, like shipyards, with radioactive waste, she said.
A behavioral difference for boys?
Male study participants were more likely than female participants to develop cancer, Smith-Bindman noted. She and Weisskopf hypothesized that the boys were more likely to play in Coldwater Creek in the aftermath of World War II.
In 1958, scientists at Washington University began collecting the baby teeth of children from St. Louis. The teeth were used in studies investigating possible links between cancer and the fallout from nuclear tests in the western U.S. St. Louis was chosen not because of its connection to uranium production but because milk in the Midwest had some of the nation's highest levels of strontium-90, a radioactive isotope produced by nuclear fission.
High concentrations of strontium-90 found in donated baby teeth contributed to the adoption of the Nuclear Test Ban Treaty of 1963. A 2011 study found that men who were children in St. Louis in the 1960s and died of cancer by middle age had more than twice as much radioactive strontium in their baby teeth as men who grew up nearby and were still alive.
Though he did not use the baby teeth in his current study, Weisskopf would like to measure strontium-90 in the teeth in a future study to assess cancer risk and actual exposure.
"As boys, they might have played in the creek way more than girls, and so they got much more exposure," he said. "If that were the case, then the radiation in the teeth should be higher in the boys than in the girls."
Given that the half-life of strontium-90 is 29 years, Weisskopf is eager to begin work on a more detailed study while radiation remains in the baby teeth.
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