Natural radioactivity in phosphate fertilizers

Abstract

Radioactive materials, like uranium and radium, are normal constituents of the earth’s crust. The radioactivity of phosphate rock is enhanced by geological processes. Exposure of workers and the public to radiation from phosphate rock and fertilizer is therefore not unlikely. The European Commission has issued a draft proposal for revision of the Basic Safety Standards for the protection of workers and the general public against the dangers of ionizing radiation. In this proposal the exposure to natural radiation sources is also regulated. The radioactivity present in some of the phosphate ores is such that the production and use of phosphate fertilizer should not be allowed without prior notification, and it is essential that a system of control be set up. The radiation dose to which workers in a fertilizer plant are subjected is not negligible, although depending on the inhalation of dust. Stocks of fertilizer form a serious radiation problem. At the retrieval of phosphate from the rock, gypsum is formed whose release causes environmental problems. The contamination of land and food with radioactivity is compared with current legislation in the Netherlands.