Using X-Ray As An Irradiation Source For Direct ESR Dating of Fossil Teeth

In this paper we have tested the potential application of X-rays as an irradiation source in Electron Spin Resonance dating of tooth enamel. Both modern and fossil samples were used to assess the feasibility of dose estimations using this alternative irradiator. Equivalent doses obtained with gamma-rays on fossil powder enamel was frequently less than the doses obtained on fragments using only X-rays. It is believed that a combination of NOCORs (non-orientated CO2- radicals) and local internal dose discrepancy may be the origin of the difference. Here, we show that testing penetration attenuation for each individual irradiation source is required to accurately estimate the maximum enamel thickness and produce reliable protocols. The use of a known laboratory additive dose allows the calculation of an absorption equivalent coefficient between gamma-rays and X-rays. We conclude that X-rays are an alternative irradiation source for ESR dating protocols, however, limitations remain in particular with alpha efficiency.

Assessment of Radioactivity Level in the Terrestrial and Marine Organisms in Yangjiang and Its Adjacent Areas (China)

In order to assess the radioactive level in the terrestrial and marine organisms in Yangjiang and the adjacent areas, 90Sr, gross beta and gamma-emitting radionuclides (238U, 226Ra, 228Th, 226Ra, 40K, 137Cs, 51Cr, 55Fe, 54Mn, 58Co, 60Co and 65Zn) were analyzed from 2011 to 2012. The annual effective doses were estimated in the high natural radioactive background areas in Yangjiang (HBRAYJ). The specific activities of 238U, 228Th, 226Ra, 40K and 137Cs in all organisms were <0.05–5.20, 0.30–14.50, 0.11–3.58, 11.1–148.0 and <0.003–0.088 Bq/kg, whilst 51Cr, 55Fe, 54Mn, 58Co, 60Co, 65Zn and 110mAg were below the minimum detectable activity. 90Sr and gross beta specific activities were 20.0–143.0 and 0.021–0.316 Bq/kg. Results show that 228Th was significantly higher than 238U and 226Ra of natural U series in organisms due to the rich-Th soils in the HBRAYJ; 228Th, 226Ra, 40K, 137Cs and 90Sr were greatly lower than the limited concentrations in Chinese foods. The internal dose mainly contributes to natural 40K, 226Ra and 228Th. It is useful to provide some basic data and assess the radiological risk from the HBRAYJ and Yangjiang nuclear power plants in future.

A Review of Dietary Intake of Acrylamide in Humans

The dietary intake of acrylamide (AA) is a health concern, and food is being monitored worldwide, but the extent of AA exposure from the diet is uncertain. The aim of this review was to provide an overview of estimated dietary intake. We performed a PubMed search identifying studies that used dietary questionnaires and recalls to estimate total dietary AA intake. A total of 101 studies were included, corresponding to 68 original study populations from 26 countries. Questionnaires were used in 57 studies, dietary recalls were used in 33 studies, and 11 studies used both methods. The estimated median AA intake ranged from 0.02 to 1.53 μg/kg body weight/day between studies. Children were represented in 25 studies, and the body-weight-adjusted estimated AA intake was up to three times higher for children than adults. The majority of studies were from Europe (n = 65), Asia (n = 17), and the USA (n = 12). Studies from Asia generally estimated lower intakes than studies from Europe and the USA. Differences in methods undermine direct comparison across studies. The assessment of AA intake through dietary questionnaires and recalls has limitations. The integration of these methods with the analysis of validated biomarkers of exposure/internal dose would improve the accuracy of dietary AA intake exposure estimation. This overview shows that AA exposure is widespread and the large variation across and within populations shows a potential for reduced intake among those with the highest exposure.

Calculation of Internal Dose and Possible Limits for Intakes of Radionuclides in Case of Plutonium Wounds

Purpose: Assessment of the degree of compliance with the principles of radiation safety and regulatory requirements in case of plutonium wounds. Material and methods: Using a wound intake of plutonium by a worker as an example, issues of the formation of the internal dose due to the wound intake and formal comparison of calculated dose values with regulatory requirements are considered. The calculations are carried out using expert analysis of the experimental data on the urine excretion of plutonium during the observation period of 7 years based on the ICRP model for direct intake into blood. In addition, calculations are carried out using prognostic assessment of the same dose values based on the biokinetic model for radionuclide-contaminated wounds published by NCRP Report No 156 together with the above model of the ICRP for plutonium compounds Strong, Colloids, Particles and Fragment. Results: Based on the calculations, possible annual limits on intakes (ALI) of radionuclides in case of plutonium wounds are derived. As criteria for determining the ALI, dose values were taken that due to the uptake of the radionuclide into the systemic circulation from the wound for any calendar year considered for 50 years after the wound intake of selected plutonium compound. Namely, the committed effective dose; the effective dose implemented in a year and the organ annual equivalent dose (to bone surface and liver). Conclusion: Based on the analysis of the above calculations, the authors formulated the formation features of the employee’s internal exposure due to wound intake of plutonium and recommendations for determining the value of plutonium intake in the wound, evaluating the effectiveness of decorporation therapy and determining the type of radionuclide compound. This allows one to more accurately assess the degree of compliance with regulatory requirements and make an informed decision on the necessary measures of medical intervention and their urgency.