Natural radioactivity in phosphates, phosphogypsum and natural waters in Morocco

The contents of natural radionuclides (uranium. actinium and thorium series ) were measured in sedimentary phosphate rock samples using high-resolution gamma spectrometry. Data obtained for uranium content (ppm) were compared with the results obtained by a method based on the measurements using solid -state nuclear track detectors (SSNTD) in the same samples. The potential l eaching of radionuclides from sedimentary phosphate rock during the industr ial production of the phosphoric acid was studied. The process of leaching of the radioisotopes from phosphogypsum was discussed. A method for the dir ect alpha counting of Ra-226 thin source. elaborated by the deposition of R a from aqueous solutions on manganese oxides film deposited on polyvinyl su pport, have been developed and applied for the determination of Ra-226 in n atural water samples. The results show that only the water sample from the mine area reveals the presence of Ra-226 at a level of about 0.2 Bql(-1) (C ) 2001 Elsevier Science Ltd. All rights reserved.