Microanalysis of Workplace Dusts from the Mixed Waste Tank Farm of the Hanford Nuclear Reservation

Abstract

In this study, radioactive particles, also known as “hot particles,” were isolated from occupational dust samples collected at the Hanford Nuclear Reservation tank farm site in Hanford, WA. The present study provides previously unreported data on the size and form of workplace dust particles, which were primarily composed of toxic or radioactive elements. Environmental transport of hot particles is affected by their size, form, and composition. Information about these physical characteristics of particles gives insight into their possible source. Hot particles isolated from two dust samples collected on different days were analyzed by scanning electron microscopy/energy-dispersive X-ray analysis (SEM/EDS). This dust analysis also detected nonradioactive fine particles (less than 10 microns in size), which were primarily composed of cadmium (Cd), lead (Pb), bismuth (Bi), and tungsten (W). Microanalysis of a sample of dust collected from the nuclear waste tank farm at the Hanford Nuclear Reservation detected a set of anthropogenic particles, including radioactive and nonradioactive isotopes of metals associated with nuclear processes, such as uranium (U), thorium (Th), plutonium (Pu), Cd, Pb, W, iron (Fe), and Bi. These anthropogenic materials were generally in the 1 to 50 micron size range, with many particles in the fine fraction below 10 microns in size.