Radionuclides In Sediment Samples Research Articles

Radiological Risk Assessment and Radioactivity Concentration in ediment of Tigris River of the Medical City/Bab Al Muadham

The concentrations of natural radionuclides in sediment samples from various locations along the stream of the Tigris riverbank in the Medical city in Bab Al- Muadham, Baghdad, had been examined using NaI(Tl) detector. The mean concentrations of specific activity for 238U, 232Th, 40K and 137Cs for sediments of the river was 13.5±4.6, 35.2±3.1, 272.2±21.4 and 1.5±0.35 Bq/kg respectively. The findings revealed that the concentration values of natural radionuclides and cesium were below permitted limits. The radiological hazard was compared with a global average (Radium equivalent, absorbed dose rate, radiation hazard index and annual effective dose equivalent) finding it was less than reported by UNSCEAR . The radium equivalent activity was 102.22 Bq/kg and the maximum absorbed dose rate was 88.1 nGy/h. At the same time, the mean annual effective dose equivalent was 420.1 µSv/y. The highest risk index was 0.39 and is much less than 1, except for the lifetime cancer risk were valuing between 164.2×10−3 to 1620×10 −3. This is a higher value than the global average.

Radiological Hazard Assessment of Radionuclides in Sediment Samples of Tigris River in Mosul city, Iraq

The natural radionuclides present in sediments such as 226Ra, 232Th and 40K contribute to the amount of radiation in a large way, as most of the population is exposed to that radiation in those areas, and calculating the value of that radiation is of great importance in knowing the radiation that humans are exposed to by measuring that values with the world recommended values. This study was conducted in order to measure the levels of natural radiation in sediments of the Tigris River in the city of Mosul, in northern Iraq, by using gamma spectroscopy technique to calculate the activity concentrations of natural radionuclides in the sediments, The results showed that the activity concentrations of 226Ra, 232Th, and 40K. ranged between (6.30±0.319-13.73±0.411) Bq.kg-1 and an average(9.86±0.385) Bq.kg-1 for 226Ra, and between (13.39±0.626-29.84±0.923) Bq.kg-1 and an average of (23.05±0.838) Bq.kg-1 for 232Th, while potassium-40 ranged between (166.83±6.456-275.96±7.601) Bq.kg-1 and with an average (232.91±6.456) Bq.kg-1 .And all the results of the activity concentration values were less than the internationally recommended values. The radiation hazard indicators were calculated on according to the activity concentrations of those natural radionuclides in the studied areas. And it was found that the value of the effectiveness of the radium equivalent was between (38.52-71.96) Bq.kg-1 and an average of (60.76) Bq.kg-1, which is less than the internationally recommended value, which should not exceed (370) Bq.kg-1,As for the value of the absorbed dose percentage Dɣ, it ranged between (17.81-33.07) nGy.h-1 and an average of (28.16) nGy.h-1

A new Certified Reference Material for radionuclides in Irish sea sediment (IAEA-385)

A new Certified Reference Material (CRM) for radionuclides in sediment (IAEA-385) is described and the results of the certification process are presented. Eleven radionuclides ( 40K, 137Cs, 226Ra, 228Ra, 230Th, 232Th, 234U, 238U, 238Pu, 239+240Pu and 241Am) have been certified and information mass activities with 95% confidence intervals are given for seven other radionuclides ( 90Sr, 210Pb( 210Po), 235U, 239Pu, 240Pu and 241Pu). Results for less frequently reported radionuclides ( 60Co, 99Tc, 134Cs, 155Eu, 224Ra and 239Np) and information on some activity and mass ratios are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in sediment samples, for the development and validation of analytical methods and for training purposes.

Distribution of 137Cs, 238Pu and 239 + 240 Pu in sediments of the southeastern Brazilian shelf–SW Atlantic margin

In this work levels of 137Cs, 238Pu and 239 + 240 Pu as well as activity ratios of anthrophogenic radionuclides in sediment samples from the southeastern Brazilian shelf are presented. Instrumental gamma spectrometry was used to determine 137Cs and alpha spectrometry to determine 238Pu and 239 + 240 Pu after a radiochemical procedure. The levels ranged from 0.30 to 1.79 Bq kg − 1 for 137Cs, from 15 to 150 mBq kg − 1 for 238Pu and, from 18 to 117 mBq kg − 1 for 239 + 240 Pu. There was a bathymetric differentiation in the radionuclides distribution. 137Cs values were generally higher in the samples collected at water depths of less than 100 m. On the other hand, plutonium isotopes exhibit higher values at greater depths. The mean ratio of 239 + 240 Pu / 137Cs obtained was 0.112 ± 0.072 which is in agreement with the value reported for the Atlantic from atmospheric fallout of nuclear explosions in the past. The 238Pu / 230 + 240 Pu ratios varied widely (from 0.339 to 2.088) and showed the influence of the SNAP-9A accident in the 238Pu levels for this area. The main goal of this work was to present unpublished anthropogenic radionuclide levels and activity ratios related to the contamination of the southeastern Brazilian shelf.