Projected Cancer Risks to Residents of New Mexico from Exposure to Trinity Radioactive Fallout.

Reference:  Cahoon, E. K., Zhang, R., Simon, S. L., Bouville, A., & Pfeiffer, R. M. (2020). Projected Cancer Risks to Residents of New Mexico from Exposure to Trinity Radioactive Fallout. Health Physics, 119(4), 478–493. https://doi.org/10.1097/HP.0000000000001333

What were the research questions?

The researchers sought to estimate the range of radiation-related excess cancers from exposure to fallout from the Trinity nuclear test among the residents of New Mexico alive at the time of the tests.

What did the research involve?

Information gained from the reconstructed radiation doses (Simon et al 2020), baseline cancer rates for the State of New Mexico and cancer risk statistical models were used to estimate the possible ranges of excess cancer risk (that is, the number of cases in addition to those normally expected) that may have resulted from the Trinity exposures.

What did they find?

The authors wrote that the cancer types and the percentage of cancers that could have been attributed to Trinity fallout varied by county of residence in 1945 in a pattern similar to the geographic pattern of fallout contamination. The largest number of excess cancer cases were projected to have occurred among people living in the five counties that received the greatest levels of fallout exposure.

Given the many uncertainties in the dose estimations and other factors the researchers highlight that the estimated radiation-related excess cancer risk is not precise. It is for this reason a range (which spans this uncertainty) is reported, in which it is believed the true number of excess cancers is likely to lie. This range shows that the number of possible cancers caused by the Trinity test is unlikely to be zero, but also unlikely to be greater than ~1,000 cases across all cancer types over the past 75 years. Among types of cancer, the fraction of cancer cases attributable to radiation exposure was highest for thyroid cancer. That is because the thyroid gland is the primary organ that concentrates radioactive iodine (I-131).

How did the researchers interpret their basic results?

They concluded that some excess cancer cases were likely to have resulted from exposure to Trinity fallout though the exact number is highly uncertain. Due to their being no cancer registry in New Mexico before the nuclear test nor during the following 20 years, it is not possible to know, with certainty, if cancer rates changed in the first decades after the test compared to before the test.

They also highlight that it is nearly impossible to derive the cause of any specific person’s cancer or other disease or to say definitively if radiation was the important factor in causing it.

Who did this research?

This study was carried out by scientists at the US National Cancer Institute and US National Institutes of Health. The research was funded primarily by the US National Cancer Institute and US National Institutes of Health with additional support from the National Institute of Allergy and Infectious Diseases.