Health risk and detection analysis of 226Ra in environmental and biological samples: A review

With the rapid advancement of unconventional fracking technologies, radium-226 ( 226 Ra), as a major radionuclide contained in drilling wastes, has attracted considerable attention from the public due to its serious health risks to humans. However, the current understanding of the health risks posed by 226 Ra remains preliminary. To better assess the health risks of 226 Ra exposure to humans, the development of highly efficient and accurate analytical methods for determining 226 Ra radioactivity in complex environmental and biological matrices is essential. This study first reviewed recent progress and developments in the health risks associated with 226 Ra exposure, based on reported epidemiological cases and laboratory studies. Subsequently, advances in detection technologies, including 222 Rn emanation, α spectrometry, γ spectrometry, liquid scintillation counting (LSC), inductively coupled plasma mass spectrometry (ICP-MS), thermal ionization mass spectrometry (TIMS), and accelerator mass spectrometry (AMS), were systematically summarized. Furthermore, the pretreatment procedure for the above measurements and its innovations were also mainly discussed, with an evaluation of their respective advantages and limitations. Finally, this review outlines the current challenges and future research directions in detecting 226 Ra in environmental and biological samples. The health risks and dose-response relationships of 226 Ra in humans were critically reviewed. 226 Ra mainly enters the human body through ingestion, and exposure to excess 226 Ra and its daughter, 222 Rn, can cause bone cancer, lung cancer, and leukemia, etc. Major pretreatment and separation methods for 226 Ra are evaluated with respect to detection efficiency, advantages and operational limitations. Radiometric and mass-spectrometric techniques (ICP-MS, TIMS, and AMS) are compared in terms of detection sensitivity, advantages, disadvantages, and application scenarios for 226 Ra.