Protection from contamination by ²¹¹At, an enigmatic but promising alpha-particle-emitting radionuclide

²¹¹At, a promising alpha-particle-emitting radionuclide, can easily volatilize and contaminate the environment. To safely manage this unique alpha-particle-emitting radionuclide, we investigated the permeability of four types of plastic films and two types of rubber gloves against ²¹¹At and identified suitable materials that prevent contamination by ²¹¹At.

Four types of plastic films, polyethylene, polyvinylidene chloride, polyvinyl chloride, and a laminated film, and two types of rubber gloves, latex and nitrile, were examined. Small pieces of filter paper were covered with these materials, and a drop containing 100 kBq of ²¹¹At was placed on them. The radioactivity of the pieces of filter paper under the materials was evaluated by measuring counts using a gamma counter and obtaining autoradiograms 3.5 h later. These experiments were also performed using ²²⁵Ac, ¹²⁵I, ¹¹¹In, ²⁰¹Tl, and ^99mTc.

²¹¹At solution easily penetrated polyethylene, polyvinyl chloride, and latex rubber. Similar results were obtained for ¹²⁵I, while other radionuclides did not penetrate films or gloves. These results suggest that halogenic radionuclides under anionic conditions are likely to penetrate plastic films and rubber gloves.

Our evaluation revealed that, when ²¹¹At solution is used, the protection by polyvinylidene chloride, a laminated film, or nitrile rubber would be more effective than that by polyethylene, polyvinyl chloride, or latex rubber.