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Based on the monitoring data of 137Cs and 90Sr in Tian Bay in 2005–2023, the impacts of the operation of Tianwan Nuclear Power Plant on the marine ecosystem were assessed. The 137Cs and 90Sr activity concentrations in the seawater and sediment varied within the background ranges. The radiation dose rates derived from 137Cs and 90Sr for the marine organisms ranged from 2.4 × 10−5 to 2.2 × 10−4 nGy/h, it was far below the most conservative screening dose rate (10 μGy/h). The committed effective dose for humans was 0.070–0.094 μSv, 1/1500th of the world's mean annual effective dose (0.12 mSv) from ingesting food containing uranium and thorium series nuclides. Radiation risk assessment showed no radiation risk for the long-term discharge of nuclear wastes in the future. Overall, the long-term normal operation of TNPPs has almost no radiation impact on the adjacent marine ecosystem. • 137Cs and 90Sr fluctuated within the background range of Tian Bay. • Dose rate from 137Cs and 90Sr to marine biota was far below the threshold (10 μGy/h). • No radiation effect on the marine ecosystem of Tian Bay from radionuclides • No radiation risk for long-term discharge of low-level radioactive waste to Tian Bay [ABSTRACT FROM AUTHOR]

Based on the monitoring data of Daya Bay in 2011–2017, the impact of long-term operation of nuclear power plants (NPPs) on the marine ecosystem was accessed. 137Cs and 90Sr in seawater and sediment of Daya Bay decreased with time. The environmental half-lives of 137Cs and 90Sr in seawater, 137Cs in sediment were 7.1 a, 11.7 a and 13.9 a, respectively. The total dose rates of the marine organisms ranged from 230.5 to 853.9 nGy/h, lower than the ERICA screening benchmark (10 μGy/h). 210Po, 226Ra and 232Th were the main dose contributors. 137Cs and 90Sr contributed to ~0.01 %–~0.06 % of the total radiation. 137Cs contributed to <0.6 ‰ of the committed effective dose for humans. There were almost no radiation effects on the marine ecosystem of Daya Bay from NPPs before 2017. In the future, there will be no radiation risk for the long-term discharge of low-level radioactive waste to Daya Bay. [Display omitted] • Environmental half-lives of 137Cs and 90Sr in seawater and sediment were estimated. • 137Cs and 90Sr only contributed ~0.01–0.06 % of the total radiation to marine biota. • No radiation effect on the marine ecosystem of Daya Bay from radionuclides • No radiation risk for long-term discharge of low-level radioactive waste to Daya Bay [ABSTRACT FROM AUTHOR]

Activity concentrations of primordial radionuclides in sand samples collected from the coastal beaches surrounding Penang Island have been measured using conventional γ-ray spectrometry, while in-situ γ-ray doses have been measured through use of a portable radiation survey meter. The mean activity concentrations for 226 Ra, 232 Th and 40 K at different locations were found to be less than the world average values, while the Miami Bay values for 226 Ra and 232 Th were found to be greater, at 1023 ± 47 and 2086 ± 96 Bq kg ̶ 1 respectively. The main contributor to radionuclide enrichment in Miami Bay is the presence of monazite-rich black sands. The measured data were compared against literature values and also recommended limits set by the relevant international bodies. With the exception of Miami Bay, considered an elevated background radiation area that would benefit from regular monitoring, Penang island beach sands typically pose no significant radiological risk to the local populace and tourists visiting the leisure beaches. [ABSTRACT FROM AUTHOR]

The levels of natural radioactivity have been investigated in some Saudi Arabian Gulf coastal areas. Sampling sites were chosen according to the presence of nearby non-nuclear industrial activities such as, the two main water desalination plants in Al Khobar and Al Jubail, and Maaden phosphate complex in Ras Al Khair, to ensure that effluents discharges into the Arabian Gulf didn't enhance radioactivity in seawater and shore sediments. Seawater samples were analyzed for radium isotopes (Ra-226 & Ra-228) and measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes by co-precipitation with MnO 2 . Shore sediment samples were analyzed for 226 Ra, 228 Ra ( 232 Th), 4 °K and 137 Cs using gamma sepectrometry. A small variation was observed in the activity concentrations of the investigated radioisotopes, and the activity levels were comparable to those reported in literature. Quality assurance and methods validation were established through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks, the analysis of standard reference materials and the intercomparison and proficiency tests. Radiological hazards were assessed, and the annual effective dose had an average value of 0.02 mSv. On the basis of the current results, we may conclude that any radiological hazards to the public visiting these shores are not expected. [ABSTRACT FROM AUTHOR]

Highlights: [•] Contamination of the ecosystem components by the radioactive isotopes 137Cs, 90Sr, 239, 240Pu. [•] The maps of the temporal–spatial change in distribution of isotopes are submitted. [•] Zones with an increased ability to accumulate these radioactive pollutants were revealed. [•] Estimations of the flows of elimination of the radionuclides into the bottom sediments were carried out. [•] Assessment of dose rates formed by 90Sr, 137Cs and 239,240Pu for Black Sea hydrobionts was obtained. [ABSTRACT FROM AUTHOR]

We studied the concentrations of terrestrial and anthropogenic radionuclides in seawater and shore sediment/sand of three selected regions; Khafji, Safaniyah and Menifah along the Saudi Arabian Gulf coast. The mean activity concentrations of the 228Ra, 226Ra, and 40K in the analyzed sand samples are 5.9, 3.5 and 113.5 Bq/kg, and the respective values in seawater samples are 1.6, 0.8 and 10.4 Bq/L. All data show lower than the corresponding UNSCEAR (2000) reported world average values of 35, 30 and 400 Bq/kg for soil matrix. A few relevant radiological hazards were quantified by the estimation of the absorbed dose rate, and the results are compared with the prescribed limits set by international regulatory bodies. Measured data indicates that the studied coastal regions pose a negligible radiological hazards to the public, and show an insignificant radioactive loading to this coastal region by the Busher nuclear power plant. • The mean activity concentrations of 228Ra and 226Ra are 5.9 and 3.5 Bq/kg. • The MDA values for the studied radionuclides were found to be 0.7 Bq/kg for 226Ra. • The studied coastal regions pose a negligible radiological hazards to the public. [ABSTRACT FROM AUTHOR]