نتایج جستجو برای: 228ra

تعداد نتایج: 109  

Journal: :Collegium antropologicum 2008
Tomislav Bituh Branko Petrinec Gordana Marović Jasminka Sencar Iva Gospodarić

The presence of natural radionuclides in Croatian rivers emphasizes the need for its continuous monitoring. Therefore results of 226Ra and 228Ra determination in Croatian river waters are presented in this paper. 226Ra and 228Ra were chosen as a possible source of human exposure due to their high radio-toxicity. Fifty liters of river water samples were collected from the Danube, Drava, Sava, Kr...

2007
WILLARD S. MOORE

High 228Ra/226Ra ctivity ratios characteristic of waters in the Amazon estuary provide a sensitive indicator of the presence of these waters in the Atlantic Ocean. A conservative mixing model utilizing the 228Ra/226Ra ctivity ratio (AR) tied to absolute measurements in the estuary allows us to estimate that 20-34% of the surface water east of the Antilles during June, 5-9% from the same area du...

Journal: :Journal of environmental radioactivity 2001
J de Oliveira B P Mazzilli M H Sampa E Bambalas

The activity concentrations of 228Ra, 226Ra and 222Rn have been analysed in 452 drinking water supplies of São Paulo State. This study started in 1994 and covered 54% of the 574 existing counties. Concentrations up to 235 and 131 mBq l-1 were observed for 226Ra and 228Ra, respectively, whereas 222Rn concentrations reached 315 Bq l-1. Radiation doses up to 0.3, 0.6 and 3.2 mSv yr-1 were estimate...

Journal: :Journal Of Geophysical Research: Oceans 2022

Radium isotopes have been used to trace nutrient, carbon, and metal fluxes inputs from ocean margins. However, these approaches require a full accounting of radium sources the coastal including rivers. Here, we aim quantify river into Arctic Ocean for first time 226Ra refine estimates 228Ra. Using new existing data, find that estimated combined (dissolved plus desorbed) annual 228Ra are [7.0–9....

M. Naseri, V. Changizi, Z. Jafarpoor,

Background: The sources of radioactivity in the environment have natural, terrestrial and extraterrestrial, and anthropogenic origins. Plants may get radioactive nuclides in two ways: (i) by the deposition of radioactive fallout, (ii) by absorption from the soil. Materials and Methods: The Concentrations of the natural radionuclides (226Ra, 228Ra, 40K) and the artificial radionuclide (...

Journal: :iranian journal of radiation research 0
v. changizi department of technology of radiology and radiotherapy, allied medical sciences school, tehran university of medical sciences, tehran, iran z. jafarpoor science and research branch, islamic azad university, tehran, iran m. naseri institute of applied physics, tehran, iran

background: the sources of radioactivity in the environment have natural, terrestrial and extraterrestrial, and anthropogenic origins. plants may get radioactive nuclides in two ways: (i) by the deposition of radioactive fallout, (ii) by absorption from the soil. materials and methods: the concentrations of the natural radionuclides (226ra, 228ra, 40k) and the artificial radionuclide (137cs) in...

2016
Matthew A Charette Phoebe J Lam Maeve C Lohan Eun Young Kwon Vanessa Hatje Catherine Jeandel Alan M Shiller Gregory A Cutter Alex Thomas Philip W Boyd William B Homoky Angela Milne Helmuth Thomas Per S Andersson Don Porcelli Takahiro Tanaka Walter Geibert Frank Dehairs Jordi Garcia-Orellana

Continental shelves and shelf seas play a central role in the global carbon cycle. However, their importance with respect to trace element and isotope (TEI) inputs to ocean basins is less well understood. Here, we present major findings on shelf TEI biogeochemistry from the GEOTRACES programme as well as a proof of concept for a new method to estimate shelf TEI fluxes. The case studies focus on...

2016
Alao A. Adewumi

Radioactivity measurements for naturally occurred radionuclides of 40K, 226Ra, 228Ra were carried out in some agricultural products harvested from two oil fields within the Nigeria Delta Region of Nigeria. The values obtained were used to determine the excess lifetime cancer risk (ELCR) and the radiation health hazard indices. Results show that the mean calculated ELCR values obtained from vege...

Journal: :International Journal of Environmental Research and Public Health 2009
Constantin Papastefanou

The radioactivity in tobacco leaves collected from 15 different regions of Greece and before cigarette production was studied in order to find out any association between the root uptake of radionuclides from soil ground by the tobacco plants and the effective dose induced to smokers from cigarette tobacco due to the naturally occurring primordial radionuclides , such as 226Ra and 210Pb of the ...

Khatoon Abbasnejad Mina Angaji Mohammad Reza Zare Vahid Changizi,

Introduction Natural and man made radioactive sources exist in our environment they can enter into our food chains. One of these is the soil-mushroom-human chain. High level doses of natural radiation can cause hazards to humans. Materials and Methods Samples of Agaricus bisporus cultivated edible mushroom in Tehran province- Iran were collected from 7 farms. Specific activity of 226Ra, 228Ra, ...

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