Analysis of the origination of gross α and gross β in natural waters
Natural water radioactivity was derived from radionuclides dissolved in water.Gross α and gross β radioactivity can reflect the overall radioactive level in various water bodies andwerescreening indicators for water quality radiation monito-ring.Primordial radionuclides such as uranium,thorium decay series nuclides and independent long-lived nuclide 40K were-the major sources of natural water radioactivity.α decay dominates in the three natural decay series of 238 U,235 U and 232 Th,and β decay was only a small part.The β decay process of 40Kwas usually the main contributor of gross β in natural waters.Except for 3H and 14C,other 20 cosmogenic radionuclides were at low levels.3H and 14C can enter the Earth'sphere through dry and wet deposition and photosynthesis and exist in natural waters.The radionuclides which was unstable to acid and heat,volatile and short half-life cannot be effectively determined by low-background measurement method and were not presented in the final apparent gross radioactive concentration results.The measurement of a single radionuclide requires specific sam-pling and preservation techniques and analytical methods.
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