No abstract

About 87% of the total dose received by the general public is due to naturally existing radioactive nuclides. Long-term exposure to the relatively long half-life radioactive elements (including Uranium, Thorium, and Potassium) and their decay products pose severe health threats to the population including lung cancer. The related available data has been collected from numerous studies conducted in China over the last two decades. Several studies have been conducted to determine the radioactive content of primordial Uranium-238, Thorium-232, Radium-226, Potassium-40, and anthropogenic Cesium-137 radionuclides in building materials, soil samples from cultivated lands, fertilizers used for reformation of soil, ash (fly, bottom) from coal fired power plant, water for irrigation and dietary items by means of High Purity Germanium HPGe or Sodium Iodide NaI (Tl) detectors. The radium equivalent activity ðRa eq Þof all the studied materials was found to be less than 370 Bq/kg except in soil from Baoji coal fired power plant (CFPP), building materials from Weinan, Xing, Fly ash from Xiangyang and coal-bearing strata from East china. The glazed tiles from Guandong, Xhaanxi, Shandong, and Zhejiang with Ra eq > 370 Bq/kg, Gamma Index ðI γ Þ > 6, corresponding to a γdose rate higher than the permissible limit of 1 mSv/yr. The volume of the gathered data is vast and scattered, and it is required to compile all data regarding the natural as well as man-made radioactivity in China. The main goal of this paper is to establish a nationwide baseline data on natural radioactivity levels by reviewing and compiling the outcomes of the conducted studies within the entire country.

Wheat flour is a dietary staple of Pakistani population. This study is mainly focused on the measurement of radioactivity concentration due to naturally occurring radioactive nuclides, uranium-238, thorium-232, potassium-40, and the corresponding hazardous radiological parameters, radium equivalent dose (Raeq), annual effective dose, internal hazard index (Hint), and ingestion effective activity \(\def\upalpha{\unicode[Times]{x3B1}}\)\(\def\upbeta{\unicode[Times]{x3B2}}\)\(\def\upgamma{\unicode[Times]{x3B3}}\)\(\def\updelta{\unicode[Times]{x3B4}}\)\(\def\upvarepsilon{\unicode[Times]{x3B5}}\)\(\def\upzeta{\unicode[Times]{x3B6}}\)\(\def\upeta{\unicode[Times]{x3B7}}\)\(\def\uptheta{\unicode[Times]{x3B8}}\)\(\def\upiota{\unicode[Times]{x3B9}}\)\(\def\upkappa{\unicode[Times]{x3BA}}\)\(\def\uplambda{\unicode[Times]{x3BB}}\)\(\def\upmu{\unicode[Times]{x3BC}}\)\(\def\upnu{\unicode[Times]{x3BD}}\)\(\def\upxi{\unicode[Times]{x3BE}}\)\(\def\upomicron{\unicode[Times]{x3BF}}\)\(\def\uppi{\unicode[Times]{x3C0}}\)\(\def\uprho{\unicode[Times]{x3C1}}\)\(\def\upsigma{\unicode[Times]{x3C3}}\)\(\def\uptau{\unicode[Times]{x3C4}}\)\(\def\upupsilon{\unicode[Times]{x3C5}}\)\(\def\upphi{\unicode[Times]{x3C6}}\)\(\def\upchi{\unicode[Times]{x3C7}}\)\(\def\uppsy{\unicode[Times]{x3C8}}\)\(\def\upomega{\unicode[Times]{x3C9}}\)\(\def\bialpha{\boldsymbol{\alpha}}\)\(\def\bibeta{\boldsymbol{\beta}}\)\(\def\bigamma{\boldsymbol{\gamma}}\)\(\def\bidelta{\boldsymbol{\delta}}\)\(\def\bivarepsilon{\boldsymbol{\varepsilon}}\)\(\def\bizeta{\boldsymbol{\zeta}}\)\(\def\bieta{\boldsymbol{\eta}}\)\(\def\bitheta{\boldsymbol{\theta}}\)\(\def\biiota{\\boldsymbol{\iota}}\)\(\def\bikappa{\boldsymbol{\kappa}}\)\(\def\bilambda{\boldsymbol{\lambda}}\)\(\def\\bimu{\boldsymbol{\mu}}\)\(\def\binu{\boldsymbol{\nu}}\)\(\def\bixi{\boldsymbol{\xi}}\)\(\def\biomicron{\boldsymbol{\micron}}\)\(\def\bipi{\boldsymbol{\pi}}\)\(\def\birho{\boldsymbol{\rho}}\)\(\def\bisigma{\boldsymbol{\sigma}}\)\(\def\bitau{\boldsymbol{\\tau}}\)\(\def\biupsilon{\boldsymbol{\upsilon}}\)\(\def\biphi{\boldsymbol{\phi}}\)\(\def\bichi{\boldsymbol{\chi}}\)\(\def\bipsy{\boldsymbol{\psy}}\)\(\def\biomega{\boldsymbol{\omega}}\)\(\def\bupalpha{\bf{\alpha}}\)\(\def\bupbeta{\bf{\beta}}\)\(\def\bupgamma{\bf{\gamma}}\)\(\def\bupdelta{\bf{\delta}}\)\(\def\bupvarepsilon{\bf{\varepsilon}}\)\(\def\bupzeta{\bf{\zeta}}\)\(\def\bupeta{\bf{\eta}}\)\(\def\buptheta{\bf{\theta}}\)\(\def\bupiota{\bf{\iota}}\)\(\def\bupkappa{\bf{\kappa}}\)\(\def\\buplambda{\bf{\lambda}}\)\(\def\bupmu{\bf{\mu}}\)\(\def\bupnu{\bf{\nu}}\)\(\def\bupxi{\bf{\xi}}\)\(\def\bupomicron{\bf{\micron}}\)\(\def\buppi{\bf{\pi}}\)\(\def\buprho{\bf{\rho}}\)\(\def\bupsigma{\bf{\sigma}}\)\(\def\buptau{\bf{\tau}}\)\(\def\bupupsilon{\bf{\upsilon}}\)\(\def\bupphi{\bf{\phi}}\)\(\def\bupchi{\bf{\chi}}\)\(\def\buppsy{\bf{\psy}}\)\(\def\bupomega{\bf{\omega}}\)\(\def\bGamma{\bf{\Gamma}}\)\(\def\bDelta{\bf{\Delta}}\)\(\def\bTheta{\bf{\Theta}}\)\(\def\bLambda{\bf{\Lambda}}\)\(\def\bXi{\bf{\Xi}}\)\(\def\bPi{\bf{\Pi}}\)\(\def\bSigma{\bf{\Sigma}}\)\(\def\bPhi{\bf{\Phi}}\)\(\def\bPsi{\bf{\Psi}}\)\(\def\bOmega{\bf{\Omega}}\)\(\left( {{I_{o,x}}} \right)\) in 12 local brands of wheat flour retailed throughout Pakistan. The radiometric assessment was performed by using a high-purity germanium detector. The specific activities (means ± standard deviations) of uranium-238, thorium-232, and potassium-40 were found to be 5.7 ± 0.41, 1.9 ± 0.02, and 132.4 ± 0.82 Bq/kg, respectively. The mean values of the corresponding radiometric variables, Raeq, Hint, and Io,x (sum), were also found to be 18.651 Bq/kg, 0.313 mSv/year, and 0.213 mSv/year, respectively. The total mean annual effective dose due to the presence of the aforementioned radionuclides in the collected samples was found to be 213.1 μSv/year, which is less than 1.00 mSv/year that is recommended by the World Health Organization and International Atomic Energy Agency. Thus, the natural radioactivity mass concentrations and the corresponding radiological variables were found to be below the recommended specific values and have no health risks for consumers. HIGHLIGHTS

Background: Cesium-137 is one of those man-made radioactive nuclides that results from human activities including open air nuclear weapons testing, nuclear accidents, operation of nuclear reactors and has a relative long halflife, higher water solubility, high fission yield, relatively high volatility and a close physic-chemical similarity to potassium that makes it a dangerous radioactive element in the human environment and is a hazardous byproduct of nuclear fission. Cesium-137 being a γ-emitter is also a potential carcinogen. Materials and Methods: A total of 100 soil samples were collected from various sites in Islamabad and its suburbs for the assessment of the presence of Cesium-137 in the environment. Spectroscopy of the collected samples for determination of aforementioned radionuclide was performed using a computer based High Purity Germanium (HPGe) detector. Results: The highest value of Cesium-137 was found to be 57.0±4.2 Bq/kg in samples collected from Nilore, a suburb of Islamabad. Conclusion: The presence of Cesium-137 in all samples is clear evidence that the studied area is contaminated either due to past fallout or ongoing nuclear activities in this area. Cesium-137 was found in higher concentration for this area than the reported values in literature for the rest of country, but not to an alarming level. However, local concerned authorities must pay attention to avoid the development of possible future health hazards to the residents of this area.