Radiological dose assessments in the northern Marshall Islands (1989--1991)

The Republic of the Marshall Islands (RMI) is located in the central Pacific Ocean about 3500 km southeast of Hawaii and 4500 km east of Manila, Philippines. It consists of 34 atolls and 2 coral island, having a total land area of about 180 km2, distributed over more than 2.5 x 106 km2 of ocean. Between 1946 and 1958 the United States conducted nuclear tests there: 43 at Enewetak and 23 at Bikini. Thirty-three years after the cessation of nuclear testing in the RMI, the impact of these operations on the health and radiological safety of the people living in or planing to return to their contaminated homelands is still an important concern. The present Brookhaven National Laboratory (BNL) Marshall Islands Radiological Safety Program (MIRSP) began in 1987 with funding from the US Department of Energy (DOE). The objectives of the MIRSP are to determine the radionuclides present in the bodies of those people potentially exposed to residual radionuclide from weapon tests and fallout, and to assess their present and lifetime dose from external and internal sources. Field bioassay missions involving whole-body counting (WBC) and urine sample collection have, therefore, been important components of the program. WBC is used to measure γ-emitters, such as 40K, 60Co and 137Cs, present in individuals. Urine samples are used to measure α and β-emitting nuclides, such as 239Pu and 90Sr, that are undetectable by WBC routine methods. 6 refs