Assessment of natural radioactivity of Vietnamese steel slag for using as landfill material

While steel slag is widely used in many countries as an environmentally benign building and backfill materials, it has not been used in Vietnam. This is because steel slag is naturally radioactive and has been treated as radioactive waste; however, there has not been any study to evaluate the natural radioactivity. This paper presents the results of an investigation and evaluation of the potential use of Vietnamese steel slag as a building material. Although the presence of natural isotopes, such as 226 Ra, 232 Th, and 40 K, were confirmed in the steel slag samples, the calculated radioactivity index I for all samples did not exceed the nominal thresholds for building construction, landfill, and landscaping applications specified in the Finland standard STUK ST 12.2/2012 and the Vietnamese standard TCXDVN 397:2007. Therefore, the Vietnamese steel slag is not a radioactive waste and can be used as building and backfill materials without environmental risk in terms of natural radioactivity. The findings of this study will be beneficial not only to Vietnam, but also to other countries that are having trouble reusing steel slag for similar reasons.