Association between radioactive fallout from 1951–1962 US nuclear tests at the Nevada Test Site and cancer mortality in midwestern US populations

Abstract

We determined the association between radionuclide deposition levels from nuclear testing at the Nevada Test Site (NTS) and cancer mortality rates in 513 counties of the Midwestern states of Iowa, Illinois, Kansas, Missouri, and Nebraska. The 10-day cumulative deposition for 54 radionuclides and 1-year cumulative deposition for 19 radionuclides were determined with isotope ratios based on each test and 131I levels in the 513 counties obtained from the US National Cancer Institute’s 131I fallout study. Deposition calculations were done for each test and each radionuclide. Age-adjusted cancer mortality rates for 84 organ-gender combinations for the periods 1950–1959, 1960–1969, 1970–1979, and 1979–1995 were used. Analyses included permutation-based randomization tests for Spearman rank correlation (adjusted for multiple testing). Age-adjusted cancer mortality rates for connective and soft tissue sarcoma, thymus, and female lymphosarcoma and cancer of the colon, brain, thyroid, and uterus were significantly correlated with total fallout and total precipitation during 1951–1957 and 1962. 187W had the highest cumulative deposition density at 10 days postshot (2783 MBq/m2) among the NTS radionuclides considered. The most significant correlations were observed for 10-day cumulative deposition density of 181W, 185W, 54Mn, 187W, 24Na, 185W, 199Au, 7Be, 60Co, and deposition density of 185W, 54Mn, 7Be, and 60Co present at 1-year with mortality for cancers such as female connective and soft tissue sarcoma, male and female thymus, female colon, male and female thyroid, female brain, male multiple myeloma, female breast, and uterine cancer. Significant correlations included isotopic forms of mutagenic metals such as antimony, beryllium, cadmium, cobalt, cesium, manganese, rhodium, selenium, tellurium, and tungsten. The large number of significant correlation tests beyond expectation warrants deeper questions related to the toxicology of fission products and induced radionuclides, validity of kriging procedures, and new studies on core sampling of watersheds and trees in regions assumed to receive the greatest levels of environmental radiocontamination.