Radioactivity Concentrations Of 40K Research Articles

Assessment of the level and risk of radioactive hazards in coastal sediments in northern Vietnam

ABSTRACT Radioactivity in coastal sediments in northern Vietnam was examined using data from five sediment cores to assess radioactivity concentrations and radiation risk indices. Radiation risk indices included radium equivalent activity (Raeq), the absorbed dose rate (ADR), the annual effective dose equivalent (AEDE), the activity utilization index (AUI), the external hazard index (Hex), the representative level gamma index (Iγr), and the annual gonadal effective dose rate (AGDE). The radioactivity concentrations of 40K, 232Th, 226Ra, 238U, and 137Cs were 567, 56.1, 35.1, 37.9, and 1.18 Bq/kg, respectively. The average concentrations of 40K, 232Th, 226Ra, and 238U were above the global average at five sites, except for 137Cs, which was low. The Raeq, Hex, and AUI indices were below the recommended values, while the AEDE, ADR, AGDE, and Iγr indices were above the recommended values. Moreover, 40K, 232Th, 226Ra, and 238U had significant impacts on the radiation hazard indices Raeq, ADR, AEDE, Iγr, AUI, Hex, and AGDE. There are three coastal sediment groups on the northern coast of Vietnam: Group 1 has a higher radioactivity and radiation risk index than Group 2 but a lower value than Group 3. Group 3 had the highest radioactivity and radiation risk index. The values of 40K, 232Th, 226Ra, and 238U and the ADR, AUI, Iγr, and AGDE indices in the sediment threaten the living environment.

AGE-DEPENDENT DOSE DUE TO INTAKE OF 40K, 228RA, 226RA IN SPRING WATER IN PETRA DISTRICT, JORDAN.

A HpGe detector was used to measure radioactivity concentrations of 40K, 228Ra and 226Ra in spring water from villages in Petra district in southern Jordan. The concentrations of 40K, 228Ra, 226Ra were 0.64-2.72Bq/l, 0.05-0.08Bq/l and 0.15-0.22Bq/l, respectively. These values were compared to the concentrations of the corresponding radionuclides in studies from Jordan and near countries. The annual effective doses (${D}_{\mathrm{eff}}$) due to the intake of 40K, 228Ra and 226Ra, for the different age groups were calculated. The highest ${D}_{\mathrm{eff}}$ values due to the intake of 226Ra and 228Ra were found in the infants age group, whereas the lowest were found in the adults age group in every site. The annual effective doses in this study were compared to the committed annual effective doses from ingestion in UNSCEAR. The annual effective doses in this study were much higher than the committed values in UNSCEAR. The life time risk for radiation-induced cancer for the whole population was calculated for every sample and it revealed no extra risk over the one recommended by WHO.

Assessment of radioactivity and radiological hazards in some flooring materials used in Karbala governorate, Iraq

The radioactivity concentrations of 40K, 232Th and 238U in 20 specimens of commercial flooring materials used in Karbala governorate, were measured using (HPGe) system. The results of measurements have shown that highest value of specific activity of for 238U which was 294.570Bq/kg (granite; Vietnamese origin), 232Th which was 88.808Bq/kg (granite; Italian origin) and 40K which was 284.580Bq/kg (marbles; Iranian origin), which were less than the worldwide average (UNSCEAR,2000). The various hazard indices were also calculated to assess the radiation hazard. It was found that none of the results exceed the recommended limit value. All specimens in this paper are within the recommended safety limit and do not present huge radiation dangers.

7 years of monitoring of 40K in surface water samples from Olt River, Romania

The aim of this study was to determine naturally occurring radionuclide 40K in surface water samples from Olt River, Romania. A monitoring study during 7 years (2012-2018) was accomplished. A number of 728 surface water samples were collected and analysed. Several hundred pollution sources were identified for the Olt River basin in Romania. This study is of particular importance since it is the first effort to evaluate the activity concentrations of 40K in surface water from Romania for such a long period. For this reason, two sampling points along the Olt River were chosen, the first one upstream of the discharge point of the magistrate channel "Deversor Olt" (reference location) and respectively the second sampling point downstream of the liquid effluents discharges point (indicator location). The radioactivity concentration of 40K was determined from the 1460.8 keV photopeak. The method used was high resolution gamma ray spectrometry performed with a hyperpure germanium detector. An activity concentration for 40K, no more than 2.14 ± 0.32 Bq l -1 , is observed, but the values recorded for the background location had a slight, but not significant difference compared with the values recorded in the second sampling point.

A two-point in situ method for simultaneous analysis of radioactivity in seawater and sediment

A new in situ radioactivity analysis method was developed to determine the fractional contributions of gamma-ray emitters in seawater and sediment from total measured counts. A semi-empirical formula to determine the fractional count contributions was derived using the variation characteristics of the gamma-ray attenuation rate and geometrical efficiency with the measurement points. The proposed method was employed to make in situ gamma-ray measurements using a CeBr3 detector for radioactivity analysis of seawater and sediment at a coastal area with a relatively high tidal range. The full energy peak efficiency of the detector at measurement site was obtained using the GEANT4 simulation code. The radioactivity concentration of 40K in seawater and sediment was determined using the proposed method and laboratory analysis with sampling. The MDA of the in situ measurement for 137Cs and 131I was also estimated assuming they were deposited on the sediment surface-layer. The validation of this method was demonstrated by comparing with the sampling analysis results.

IN-SITU GAMMA-RAY SPECTROMETRY FOR RADIOACTIVITY ANALYSIS OF SOIL USING NaI(Tl) AND LaBr3(Ce) DETECTORS.

In this study, the full energy peak count rates to radioactivity conversion factors of 3″Ø × 3″ NaI(Tl) and 2″Ø × 2″ LaBr3(Ce) detectors for radioactivity analysis in the soil were determined on site using a semi-empirical method with point-like gamma-ray sources. To validate the conversion factors derived for the detectors, in-situ gamma-ray measurements were performed in wide open fields with almost flat surface and compared with the sampling analysis for the radioactivity of U-series, Th-series, and 40K in the soil. As a result, radioactivity concentrations of 40K, 208Tl and 214Bi by in-situ and laboratory measurements agreed well with each other within 5%, and the MDAs for artificial radionuclides were estimated under the condition of fresh deposition considering a radiation emergency situation.

In-situ CeBr3 gamma-ray spectrometry for radioactivity analysis of soil

A CeBr3 scintillation detector was applied for in situ gamma-ray spectrometry for radioactivity assessment of soil. The full energy peak count-to-radioactivity conversion factors were determined using a semi-empirical method. In-situ measurements using the detector system were implemented in three open fields. The radioactivity concentration of natural radionuclides in the soil and the detection limit for artificial radionuclides assuming artificial radionuclide deposited on the soil surface in a radiation emergency situation were estimated. The radioactivity concentration of 40K, 208Tl and 214Bi by in situ gamma-ray measurement agreed well with the sampling analysis results within 5%.

Measuring the radioactivity concentration of 40K and 137Cs and calculating the annual internal doses from ingesting liquid and powdered milk

Thirty-three samples of powdered milk and thirteen samples of liquid milk (mostly imported from several countries) were collected from the local market in Saudi Arabia to measure the activity concentrations of artificial and natural radionuclides and evaluate the safety of milk for humans. Spectrometric analysis using the HPGe detector was performed. The results show that the activity concentration of 40K in powdered milk ranged between 130 ± 7 and 595 ± 32 Bq kg–1 (average 285 ± 29 Bq kg–1), and that of 137Cs ranged between 0.05 ± 0.02 and 1.3 ± 0.2 Bq kg–1 in powder milk. In liquid milk, the activity concentration of 40K ranged between 40 ± 2 and 98 ± 5 Bq L–1 (average 66 ± 4 Bq L–1), and that of 137Cs was 0.12 ± 0.03 Bq L–1. The annual internal dose for 40K and 137Cs was calculated, and it is lower than the regulated dose.

Determination of the Background Radiation Level in Mosul University Campus Using Multiple Technologies

The current study aims to determine the background radiation level in Mosul University Campus using multiple technologies, portable detector type Inspector EXP+ containing Geiger-Mueller tube, NaI(Tl) and CR-39 detectors. The portable detector was used to measure the dose rate (Dexp.) at 1 m height from the ground. The radioactivity concentrations of 40K, 222Rn, 226Ra, 232Th, the dose rate (Dcal.) at 1 m height from the ground, radium equivalent activity (Raeq), gamma index (Iγ), alpha index (Iα), external hazard index (Hex), internal hazard index (Hin) and radon exhalation rate (E) were calculated. An empirical equation between the field and the laboratory measurements of the dose rate in air (Dcal., Dexp.) and other equations between (Iγ, Dcal.), (Iγ, Raeq), (Iγ, Hex) and (Raeq, Hex) were found.

Determination of radioactivity levels in Akhisar, Gördes, Gölmarmara and Sindirgi regions, Western Turkey

In this study, radioactivity measurements in the environment of Akhisar, Golmarmara, Gordes and Sindirgi regions in Western Turkey were investigated in order to evaluate the implications of any excess radioactivity in the environment of geological formation. The radioactivity concentrations of 40K, 238U and 232Th radionuclides in the soil samples were measured by a NaI(Tl) gamma spectrometer system, and the radium activity concentrations in the water samples were also analyzed by an ZnS(Ag) alpha counter by the collector chamber method. The radioactivity of 40K, 238U and 232Th in soils ranged 2.80–2,347.77, 9.90–256.19 and 9.66–106.53 Bq kg−1, respectively. The activity of 226Ra in the water samples ranged from 0.03 Bq L−1 (0.89pCi/L) to 0.80 Bq L−1 (21.58pCi/L). In addition, the external terrestrial gamma dose rate in air (nGy h−1), annual effective dose rate (mSv year−1) and radium equivalent activity (Bq kg−1) were calculated and compared with international standard values.

Natural Radionuclide Concentrations and Radiological Impact Assessment of River Sediments of the Coastal Areas of Nigeria

This work was carried out to measure the radioactivity level in the coastal areas of Nigeria by gamma counting of river sediment samples and assess the radiological impact associated with the use of the river sediments as building material. The method of gamma spectrometry with a 7.6 cm by 7.6 cm NaI(Tl) detector was employed in determining 40K, 238U and 232Th levels in 95 and 38 sediment samples respectively collected from representative sites in the oil producing and non oil producing coastal areas of Nigeria. Results of the samples assayed showed that the radioactivity concentrations of 40K, 226Ra and 228Ra in the sediment samples of oil producing areas range from 95.4 to 160.0; 7.6 to 31.0 and 9.5 to 41.6 Bq kg–1, respectively. The respective means were calculated as 122.39 ± 47.49; 18.93 ± 12.53 and 29.31 ± 18.67 Bq kg–1. In the sediment samples from the non oil producing areas, the respective mean values are 88.48 ± 8.22, 14.87 ± 3.51 and 16.37 ± 3.87 Bq kg–1. Statistical analysis of the results showed that there is no significant difference between the radionuclide concentration of the sediment samples from different rivers in the oil producing and non oil producing coastal areas, except for 40K. The values of the natural radionuclide concentrations however translate to the determina-tion of the radiological impact assessment values. The values of the radiological assessment indices obtained were ob-served to be lower than limits internationally reported and recommended for building materials. It could therefore be reported that the operations of the oil companies in the coastline, involving use of radioactive materials have not contributed adversely to the radioactivity level of the river sediments and that the use of river sediments as building mate-rial in the coastal areas of Nigeria poses no radiological risk.