Committed effective dose from naturally occuring radionuclides in shellfish

The environment of the Straits of Malacca receives pollution as a result of various industrial and anthropogenic sources, making systematic studies crucial in determining the prevailing water quality. Present study concerns concentrations of natural radionuclides and heavy metals in marine fish (Rastrelliger kanagurta) collected from the Straits of Malacca, since aquatic stock form an important source of the daily diet of the surrouding populace. Assessment was made of the concentrations of key indicator radionuclides (226Ra, 232Th, 40K) and heavy metals (As, Mn, Fe, Cr, Ni, Zn, Cu, Co, Sr, Al, Hg and Pb) together with various radiation indices linked to the consumption of seafish. The annual effective dose for all detected radionuclides for all study locations has been found to be within UNSCEAR acceptable limits as has the associated life-time cancer risk. The overall contamination of the sampled fish from heavy metals was also found to be within limits of tolerance.

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Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca.

This handbook is based on an earlier French laboratory guidebook A Guide on Radionuclides and Radioprotection by D Delacroix et al published in 1994. The earlier publication was orientated towards guidance on the handling of radionuclides used in medicine. The main purpose of this handbook is the provision of data sheets and the models or references used to assemble the data, rather than as a protection guide for laboratory users. The book is intended for radiation protection specialists and possibly for others who transport radionuclides. Thankfully, the authors have restricted the models and references to nine pages and the remaining 107 pages are devoted to data sheets covering a wide spectrum of nuclides. Each data sheet is identical in layout, which at first appears complex but, with a little effort, becomes clear and concise. The data sheets have been designed as a ready reference source covering a variety of up-to-date isotopic and radiation protection data. These include: half-life and specific activity main emissions IAEA Basic Safety Standard exemption levels IAEA and transport values external exposure data covering a range of standard laboratory handling techniques contamination information including skin dose and recommended probes shielding data ICRP ingestion and inhalation doses per unit intake 20 mSv ALI values and highest organ doses. In summary, the book provides a useful guide for those who require practical advice regarding the radiation protection data for a number of nuclides, but it will need to be supplemented if readers are interested in interpreting and applying the data in the workplace.

Radionuclide and Radiation Protection Data Handbook

A study on the impact of phosphate fertilizers on the radioactivity profile of cultivated soils in Srirangam (Tamil Nadu, India)

The activity concentrations of naturally occurring radioactive materials such as (226)Ra, (238)U, (232)Th, (40)K and (137)Cs were measured for 44 plant samples collected from different locations in the northwestern region of the West Bank, Palestine, using high-resolution gamma ray spectroscopy. The activity concentrations of radionuclides in the investigated plant samples ranged from 7.5 to 157.6 Bq kg(-1) for (226)Ra, 7.5 to 66.1 Bq kg(-1) for (238)U, 1.8 to 48.5 Bq kg(-1) for (232)Th, 14.3 to 1622 Bq kg(-1) for (40)K and <0.1 to 4.7 Bq kg(-1) for (137)Cs. The average values of these activities were 48.3, 26.5, 10.1, 288.0 and 2.2 Bq kg(-1), for (226)Ra, (238)U, (232)Th, (40)K and (137)Cs, respectively. The study presents the total gamma radiation dose rate assessed from natural radionuclides,(137)Cs and cosmic radiation, the dose rate of each radionuclide and the effective dose for all the samples. The radiological health implication to the population that may result from these doses is found to be low, except in few cases. The measurements have been taken as representing a baseline database of values of these radionuclides in the plants in the area.

Radioactivity levels in plant samples in Tulkarem district, Palestine and its impact on human health.

The specific activity concentration and the derived Annual Effective Dose(AED) in three types of vernonia cultivated and consumed within and outside Cameroon were measured by means of a well-calibrated high-purity germanium detector. Vernonia samples were collected directly from the production farms, oven-dried to a constant mass, crushed, sieved and sealed for at least a month before analysis. The specific activity of 238U in the three types of vernonia ranged from 20 - 50 Bq kg-1 with an average of 42 ± 15 Bq kg-1, 232Th from 9 - 22 Bq kg-1 with an average of 17 ± 7 Bq kg-1 while 40K ranged from 115 - 460 Bq kg-1 with an average of 302 ± 36 Bq kg-1. The average AED for 40K, 238U and 232Th were 0.15, 0.92 and 0.92μSv y-1 respectively. 238U and 232Th show the same trends both for the regional distribution of the radioactivity content and the AED. The discrepancies in our data can be attributed to many factors such as geological formation, foliar deposition, type and age of the plant, etc. Although the results obtained represent only some fractions of the standard limit, but they are within some range obtained in other countries.

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Investigation of Gamma-Emitting Natural Radioactive Contents in Three Types of Vernonia Consumed in Cameroon

A survey of radioactivity content and associated radiological risks was carried out in various soils used for agriculture and building materials in Cameroon by means of a well-calibrated high-purity germanium detector. Soil samples were collected directly from the agricultural farms and the brick’s factories, air-dried at room temperature to a constant mass, crushed, sieved and sealed for at least one month before analysis. The specific activity of 238U ranged from 5.36 ± 0.39 to 51.28 ± 9.67 Bq﹒kg–1 with an average of 34.52 ± 7.18 Bq﹒kg–1; 232Th from 4.03 ± 1.03 to 24.74 ± 3.10 Bq﹒kg–1 with an average of 16.67 ± 4.28 Bq﹒kg–1; 40K ranged from 16.18 ± 3.11 to 467.40 ± 50.80 Bq﹒kg–1 with an average of 186.96 ± 16.21 Bq﹒kg–1; while that of the fallout 137Cs ranged from 0.00 to 4.79 ± 1.75 Bq﹒kg–1with an average of 2.32 ± 0.99 Bq kg–1; The mean result obtained for the Representative levels index (Iγ), the radium equivalent (Raeq), the total absorbed dose rate (ADR), the external hazard index (Hex), the internal hazard index (Hin) and the Ceasium intervention levels were 0.52, 72.75 Bq﹒kg–1, 33.73 nGy﹒h–1, 0.20 Bq﹒kg–1, 0.29 Bq﹒kg–1 and 0.0028 Bq﹒cm2 respectively. The discrepancies of our data can be attributed to several factors such as past nuclear disasters, geological formation, transport process, etc. Although our results are just some fractions of the international standard limit, but still within the same ranges when compared with those obtained elsewhere. This results also will serve as a baseline data for future investigations.

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Assessment of Radioactivity Contents and Associated Risks in Some Soil Used for Agriculture and Building Materials in Cameroon

The focus of this study was to investigate the activity concentrations of 40K, 238U and 232Th in edible leaves of Vernonia amygdalina (VA) and Vernonia calvoana (VC) and to derive from these activity concentrations, the associated Radium equivalent, the gamma dose rates, and the Internal hazard index (Hin). The average activity concentrations for 40K, 238U and 232Th found in the fresh leaves of VA and VC was: 29.10 ± 3.01; 4.25 ± 1.56; 1.67 ± 0.76 Bq.Kg-1 and 32.56 ± 3.50; 4.50 ± 1.68; 1.68 ± 0.72 Bq.Kg-1 respectively. The average radium equivalent activities obtained for fresh leaves were 6.79 ± 2.84 Bq/kg and 6.79 ± 2.97 Bq/kg. The gamma dose rate of 3.94 and 4.12 then the hazard index of 0.026 were found both in VA and VC leaves samples.

Thomas B. Makon

Papers

Investigation of Gamma-Emitting Natural Radioactive Contents in Three Types of Vernonia Consumed in Cameroon

Assessment of Radioactivity Contents and Associated Risks in Some Soil Used for Agriculture and Building Materials in Cameroon

Assessment of Radioactivity Levels for 40K, 238U and 232Th in Edible Leaves of Vernonia amygdalina and Vernonia calvoana

Linear Spaces of Permutomers and Symmetry Itemized Isomers Numbers of C2v-based Cuneane Derivatives and Heteroanalogues. II