Spatial Distribution of Total 210Pb in the Marine Sediment of Peninsular Malaysia: Radioactivity Level Variations in The Sunda Shelf Seas

Radiochemical separation techniques were applied to measure 210Pb radioactivity in the samples to determine spatial distribution of total 210Pb radionuclide in surface sediments and water column for the main waters on the Sunda Shelf. The average 210Pb radioactivity level recorded from the Malacca Strait (MS) is significantly higher than the southern South China Sea (sSCS); this is attributed to the supply of input from the Andaman Sea in its northern areas, and massive terrestrial processes from bordering land masses. The results reveal that the decreasing trend of total 210Pb in Peninsular Malaysia’s marine sediment starts with the north maritime zone of Malacca Strait (64.28 ± 5.97 Bq/kg) > south maritime zone of Malacca Strait (50.88 ± 6.15 Bq/kg) > east maritime zone of sSCS (41.01 ± 3.07 Bq/kg) > south maritime zone of sSCS (40.78 ± 3.16 Bq/kg). The Kelantan and Pahang Deltas have been identified as two of the main anthropogenic sources of input for total 210Pb in the sSCS while atmospheric transboundary mobilization affecting total 210Pb in water column. In the Malacca Strait, however, the distribution of total 210Pb might be influenced mainly by in situ processes of the strait’s seafloor and sources origin of sediment.

Determination of Gross Alpha and Gross Beta Activity Concentration in Bahe River Water Samples Within Xi'an Chanba Area

As a screening procedure, gross alpha and gross beta activity have been developed to determine whether further analysis of water samples related to specific radionuclide is necessary. In China, the determination of gross alpha and gross beta in drinking water was generally based on the HJ standard method: HJ 898-2017, water quality — determination of gross alpha activity — thick source method, and HJ 899-2017, water quality — determination of gross beta activity — thick source method. In this study, 15 water samples from Bahe river in Chan Ba region of Xi’an in China, were pretreated and analyzed by BH1216-III low background alpha and beta scintillation counter. The water samples were collected nearby residential area, wetland park, water conservation district and urban sewage treatment plant as well as other important locations which probably influence on the radioactivity level. The values of the activity concentrations of the gross alpha and beta measured in the water samples ranged from less than LD to 0.183Bq/L with a mean of 0.077Bq/L and 0.073–0.151Bq/L with a mean 0.102Bq/L respectively. All values of samples were lower than the limit level of 0.500Bq/L for gross alpha and 1.000Bq/L for gross beta, indicating that the radioactivity level in Bahe water between Chan Ba region of Xi’an is basically within the normal environmental background.

Uranium Radioactivity Measurement for Low-Level Wastewater Based on Ultra-Low Level Liquid Scintillation Analyzer

In this paper, a method based on ultra-low level liquid scintillation analyzer for measuring uranium radioactivity in low-level radioactive wastewater is proposed. It can easily and quickly measure the radioactivity level of uranium in samples, and even distinguish the main isotopes of uranium. In low-level wastewater samples, if the uranium isotope has the same or similar composition and ratio to the natural uranium isotope, Comparing to the results in units of mass concentration given by laser-fluoremetry method, the liquid scintillation method can give the results in units of activity concentration, and these two results with different units can interconvert to each other. However, interconversion of results on above two measurement methods cannot be applied in low-level wastewater after uranium enrichment, because the proportion of isotopes with high specific activity in above wastewater, such as 234U and 235U, is significantly higher than that without enrichment. The measurement results in units of mass concentration will underestimate the uranium radioactivity level of the sample. The liquid scintillation method directly gives the results in units of radioactivity activity concentration, and it is more convenient to compare with relevant national standards to determine whether the emission standards are met. The lowest limit of detection of this method is 0.014 Bq L−1 within 600 min.

Assessment of Environmental Radioactivity Level and its Health Implication in Imiringi Community Bayelsa State, Nigeria

A total forty two (42) sampled points were investigated for radioactivity level and health implication using standard method. The exposure dose rate ranged from 14 to 32μRh-1 with an average value of μ23Rh-1. Dose rate and equivalent dose rate ranged from 121.8 to 278.4nGyh-1 and 1.18 to 2.69mSvy-1 respectively. The average value of the indoor annual effective dose equivalent (AEDE), outdoor AEDE, and excess lifetime cancer risk (ELCR) were computed to be 0.936 mSvy-1, 0.311 mSvy-1 and 0.810 x 10-3 respectively. Analysis of dose to human organs; testes and ovaries, were 0.61 and 0.43 mSvy-1 respectively. Exposure rate, dose rate and ELCR exceeded the recommended values. All the outdoor AEDEs were within the permissible value of 1.0 mSvy-1 for general public and below the limit of 20 mSvy-1 for radiological workers as recommended by InternationalCommission on Radiation Protection (ICRP). Keywords: Assessment, Environmental radioactivity, Exposure dose, Health impact