Specific Activities Of 40K Research Articles

Measurements of natural radionuclide levels and hazards in the Lega Dembi gold mine, Oromia, Ethiopia

ABSTRACT This study aimed to evaluate natural radioactivity levels and hazards of radionuclides 232Th, 226Ra and 40K in soil samples taken from 15 locations in the Lega Dembi gold mining, Oromia, Ethiopia, using gamma-ray spectroscopy coupled with an HPGe detector. It was observed that the respective mean specific activities for 226Ra, 232Th and 40K determined in the mining site were 23.87 ± 0.7, 52.5 ± 1.8 and 391.62 ± 11.35 Bq/kg, and 8.89 ± 0.4, 13.83 ± 0.6 and 423.68 ± 9.5 Bq/kg in the living areas. The specific activity of 232Th was above the permissive limit in the mining site, while for 226Ra and 40K were within the limit. The specific activity of 40K in the living area was observed to be above the permissive limit. The calculated value of radiation hazards parameters; radium equivalent activity (Raeq), internal and external hazards indices (Hin) and (Hex), the mean annual effective dose (AED), and gamma representative indices (Iγ) were within permissively limit. The mean absorbed dose rate in the mining site was above the recommended safety limit. The total annual gonadal dose equivalent value was found to be 494.8 ± 8.7 µSv/a in the mining site. This value was also above the permissively.

Background gamma radiation and associated health implications for Ifo-Dagbolu-Ajakaye, Ogun state

The need for safe habitat in view of the demands of Sustainable Development Goal 3 - sound health and wellbeing, calls for attention to ascertain the level of exposure of gamma radiation to man and the environment. Keeping the levels of specific activities of naturally occurring radionuclides (NORs) within safety limits will help in attaining the Sustainable Development Goal 3-“Good Health and Well-being”. Background gamma dose rates and activity concentrations of NORs: 40K, 238U, and 232Th in an agrarian settlement, Ifo-Dagbolu-Ajakaye, Ogun State, Southwest Nigeria, was surveyed using an Ultra-rugged Super-spec RS-125 gamma spectrometer. The respective mean values of the background gamma dose rates and specific activities of 40K, 238U, and 232Th were 14.96 nGyh−1; 31.60, 16.54 and 12.91 Bqkg−1. The values of the specific activities were used to estimate the associated radiological health parameters and the values obtained were lower when compared with their corresponding United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) permissible limits. Hence the levels of the activity concentrations of the studied NORs do not present health hazards to the dwellers in the examined station.

Estimation of the total body burden for some individuals using whole body counter

The current research study aims to estimate the total body burden and internal contamination for some public and occupational workers at Nuclear Research Center, NRC, and Egypt using Accuscan II whole body counter. Material and Method WBC consist of three parts; 25% coaxial germanium detector connected with electronic circuits, Shadow shield and transfer phantom. The WBC was used to monitor the workers and public for the 99mTc, 131I and 40K in the total body geometry for acquisition time of 300 sec. The efficiency calibration was carried out for wide energy range from 59 keV to 1836.2 keV using a standard mixed source. A liquid vial mixed gamma source inserted in thyroid and total body geometry positions of transfer phantom. In addition, KCl salt is inserted in total body geometry position of transfer phantom in real geometry to confirm the calibration of 40K in the energy of 1460 keV. Results The minimum detectable amount for 99mTc, 131I and 40K was 178, 172 and 204 Bq respectively. 40K body content activity for males ranged from 3497 to 5594 Bq and specific activity of 40K was ranged from 43.7 to 75.3 Bq/Kg and for females ranged from 2797 to 4544 Bq and 40K specific activity ranged from 31.1 to 64 Bq/Kg. The annual internal effective dose from 40K for males ranged from 122 to 210 μSv with an average dose of 165 μSv and for females ranged from 86 to 163 μSv with an average dose of 135 μSv. Internal dose for individuals exposed to I131 ranged from 0.45 μSv to 168.5 μSv and for individuals exposed to 99mTc ranged from 1.78 μSv to 3.25 μSv. The estimated annual effective dose for 40K, 131I and 99mTc was within the ICRP recommendations.

Assessment of Natural Radio Activity Level in Some Imported Food Products in the Iraq Markets

The current study includes the evaluation of the levels of natural radioactivity of some nuclei in food samples included of 12 rice, and 8 legumes. Local markets in the Iraqi city of Hilla were sampled and spectral measurements were carried out using the reagent system sodium activated iodide thallium (NaI (Tl)) (3 3). 238U (214Bi), 232Th, and 40K had average values of (16,580.5278, 20,241.0849), and (388.87023.0914, respectively) of Bq/kg in rice samples, according to the study. (214Bi), (232Th), and 40K were all within the range of samples of legumes (7.46), (20.68) (322.57). All these results for the average specific activities of 238U(214B), 232Th and 40k were compared with the limits recommended by UNSCEAR (32)Bq/kg for specific activity of 238U (214B), (45)Bq/kg for specific activity of 232Th, (412)Bq/kg for specific activity of 40K and found to be below those values. Also, it was found that, the internal hazard index were (0.243) Bq/kg in samples of rice and the Extranl hazard index were(0.194 these results for the average value of the internal hazard index were compared with the limits recommended by UNSCEAR (1) for internal hazard index and found to be below those values. Accordingly, most of the food models that examined are considered honest in terms of contamination of nuclear radiation naturally.

Assessment of Background Radioactivity and Related Radioactive Hazard Indices in Glutinous Rice (Oryza sativa var. glu-tinosa)

Specific activites of natural (40K, 226Ra and 40Th) and anthropogenic (137Cs) radionuclides in 30 glutinous rice samples bought from some local retailers and department stores in Songkhla Province have been measured and analyzed. Experiment results were carried out by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system at Radiation Laboratory in Thailand Institute of Nuclear Technology (Public Organization) (TINT). The results show that the specific activities of 40K, 226Ra, 232Th and 137Cs in 30 glutinous rice samples ranged from < 592.21 – 896.36, < 3.73 – 11.92, < 2.49 – 7.84 and < 1.54 – < 2.35 Bq/kg respectively, with mean values of 683.13 ± 33.61, 6.09 ± 1.78, 4.20 ± 1.52 and < 1.92 ± 0.21 Bq/kg respectively. Furthermore, some related radioactive hazard indices and the excess lifetime cancer risk (ELCR) value were also evaluated and found in the safety values. Moreover, all the results were compared with Office of Atoms for Peace (OAP) data, research data in Thailand, international studies and some recommended values.

Determination of Activity Concentrations and Soil to Cassava Transfer Factors of Natural Radionuclides in Ikot Ekpene Local Government Area, Akwa Ibom State, Nigeria

Natural radioactivity exists in primordial formations such as rocks, soils, water and air where long lived radionuclides such as , , and their affiliates are found. This work was done to determine the specific activity of radionuclides, soil to cassava transfer factor and the effective dose due to consumption of radionuclide in cassava products in Ikot Ekpene Local Government Area, Akwa Ibom State. The specific activity of 40K, 238U and 232Th in soils and cassava in the study area was measured using gamma spectrometry. Mean specific activity in soils ranged from BDL to 153.46 ± 10. 99 Bq/Kg for 40K; BDL to 31. 22 ± 7.49 Bq/Kg for 238U and 1.03 ± 0.10 to 12.71 ± 1.24 Bq/Kg for 232Th. Mean specific activity of the radionuclides in cassava in all locations ranged from 119.86 ± 8.61 to 601.28 ± 43.23 Bq//Kg for 40K; below detectable limit (BDL) to 15. 89 ± 1.55 Bg/Kg for 238U and BDL to 15. 89 ± 1.55 Bq/kg for 232Th. Transfer factors ranged between 3.64 to 4.18 for 40K; 1.30 to 1.82 for 238U and 0.51 to 0.72 for 232Th. Effective ingestion dose due to the consumption of cassava from the area ranged between 0.99 mSv/yr to 1.08 mSv/yr and 2.68 mSv/yr to 29.16 mSv/yr for children and adult respectively. Most of the TF and effective ingestion dose results for this study were above the recommended value of unity which suggests that consumption of cassava from the studied area may pose radiological health.

Investigation and Analysis of Soil Radioactivity Level in Parks in a City

Using a portable microcomputer multi-channel gamma spectrometer to directly measure the radioactive content in the soil, the on-site gamma energy spectrum measurement was carried out on the soil of 7 parks in a certain city. The survey results show that the specific activity of 40k in the urban park soil ranges from 470.88 bq/kg to 640.2 bq/kg. The specific activity of 238u ranges from 26.77 bq/kg to 33.31 bq/kg. The specific activity of 232th ranges from 42.14 bq/kg to 54.72 bq/kg. The content of the three radionuclides in the soil in the park is lower than the national average, and far lower than the radioactivity of ordinary building materials.

The Natural Radioactivity in Food: A Comparison Between Different Feeding Regimes

Background: In this article a comprehensive study was carried out for the determination of natural radioactivity in animal and vegetable food (meat, fish, milk and derivates, legumes, cereals and derivates, fruit, hortalizas, vegetables, vegetable oils) typical of different feeding regimes, for the age category higher than 17 years. Methods: A total of eighty-five samples of Italian origin, coming from large retailers during the years 2014, 2015 and 2016, were analyzed through HPGe gamma spectrometry. Results: The specific activity of 40K was investigated and its mean value was found to be: (106.3 ± 6.9) Bq/kg for bovine, swine and sheep meat; (116.5 ± 9.7) Bq/kg for fish; (52.9 ± 3.1) Bq/kg for milk and derivates; (271.9 ± 16.7) Bq/kg for legumes; (67.2 ± 4.7) Bq/kg for cereals and derivates; (52.7 ± 4.4) Bq/kg for fruit; (72.9 ± 5.6) Bq/kg for hortalizas; (83.9 ± 6.5) Bq/kg for vegetables; lower than the minimum detectable activity for vegetable oils. For animal food the highest mean 40K activity concentration was found in fish samples; for vegetable food the highest one was detected in legumes. Conclusion: The evaluation of dose levels due to the food ingestion typical of Mediterranean, Vegetarian and Vegan diets was performed. The annual effective dose was found to be 0.16 mSv/y, 0.41 mSv/y and 0.54 mSv/y, respectively.

Assessment of natural radioactivity levels and annual equivalent doses in some milk powdered samples for adults used in Baghdad

In this paper the specific activity of 238U, 232Th and 40Kradionuclides were determined by sodium iodide enhanced bythallium NaI(Tl) detector and assessment the annual effective dosein samples of powder milk from different companies such asAlmunaish, Seven Caw, Molty and Altunsa for adult available inBaghdad markets. The specific activity of 40K has the greater value inall the samples which is in the range of allowed levels globally thatsuggested by UNSCEAR. The mean value of annual effective doseswere 0.121, 0.314775 and 0.305 mSv/y for 238U, 232Th and 40Krespectively.

Radioactive Element Distribution Characteristics of Red Mud based Field Road Cement before and after Hydration

Red mud was firstly used as a raw material in sintering field road cement. Then, the radioactive element distribution characteristics of red mud based field road cement (RFC) before and after hydration were comparatively investigated. The experimental results indicated that the specific activity of 226Ra and 232Th increased after sintering process from raw material to clinker, as a result of concentrating effect on 226Ra and 232Th during sintering process, but the specific activity of 40K decreased after sintering process as a result of volatilization effect. Radionuclide 226Ra mainly distributed in RFC silicate phases (C x S), 232Th distributed more in RFC interstitial phases than RFC silicate phases (C x S), 40K mainly distributed in RFC interstitial phases. With increasing hydration ages of RFC pastes, the specific activity of 226Ra kept increasing, 232Th remained consistency all the same and 40K declined. The radioactivity of RFC was in the recommended safe limit of Chinese National Standards GB6566-2010 during its preparation and application process.

Specific Activities of Natural Radionuclides and Annual Effective Dose Due to the Intake of Some Types of Children Powdered Milk Available in Baghdad Markets

In this research the specific activity of natural radionuclides 226Ra, 232Th and 40K were determined by sodium iodide enhanced by thallium NaI(TI) detector and assessed the annual effective dose in Dielac 1 and 2 and Nactalia 1 and 2 for children of less than 1 year which are available in Baghdad markets. The specific activity of 40K has the greater value in all the types which is in the range of allowed levels globally that suggested by UNSCEAR. The mean value of annual effective doses were 2.92, 4.005 and 1.6325 mSv/y for 226Ra, 232Th and 40K respectively.

Measurement and Analysis of Specific Activities of Natural Radionuclides (40K, 226Ra and 232Th) in Beach Sand Samples from Talo Kapo Beach of Yaring District in Pattani Province using Gamma Ray Spectrometry

The Specific Activities of 40K, 226Ra and 232Th were studied and determinate for 30 beach sand samples collected from Talo Kapo beach of Yaring district in Pattani province. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system. The IAEA-SOIL-6 reference materials obtained from the International Atomic Energy Agency were also used to analyze and compute the 40K, 226Ra and 232Th specific activity in all 30 beach sand samples. The measuring time of each sample is 10,000 seconds. It was found that specific activity range from 1805.37 – 3323.05, 40.96 – 2137.36 38.63 – 4329.28 Bq/kg for with mean values of 2242.79 ± 117.40, 250.18 ± 8.21 and 458.42 ± 7.68 Bq/kg for 40K, 226Ra and 232Th, respectively. Moreover, the results were also compared with research data in the south of Thailand, the Office of Atoms for Peace (OAP) annual report data and the recommended values which were proposed by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR,)

Measurement of radioactivity level of sand fraction of Nigerian oil sands for environmental impact assessment

ABSTRACTThe radioactivity level of the sand fraction of Nigerian oil sands collected from four different locations, namely Ilubirin, Olowo-Irele, Loda, and Orisunbare, Ondo State, Nigeria, were identified and quantified with the view to assess its likely environmental and health impact of the exploration, exploitation, processing, and transportation of the fossil fuel. Soxhlet extractor was used to extract bitumen from the oil sand samples using toluene as extracting solvent. The sand fraction as left-over collected from the thimble after exhaustive extraction was dried in the oven at 70°C for 8 h to remove trace water and extracting solvent. A survey of radioactivity content and associated radiological risks was carried out on the sand fraction samples by means of a well-calibrated gamma-ray spectrometer containing Na-I (Tl) detector. The mean specific activities of 40K, 232Th, and 238U present in the analyzed sand fraction samples were 3131.17 ± 5.71, 147.90 ± 10.85, and 96.28 ± 2.59 Bq/kg, respectively. The results obtained for the absorbed dose rate (AD), annual effective dose rate (AEDR), internal hazard index (Hin), external hazard index (Hex), annual gonadal equivalent dose (AGED), and the representative levels index (Iγr) were 264.380 nGy/h, 0.324 mSv/year, 1.461 Bq/kg, 1.481 Bq/kg, 1903.073 µSvy–1, and 2.185, respectively. The AD values were higher than the population weighted average (60 nGy/h) recommended by UNSCEAR. The Hex and Hin values were above unity for the studied samples except from Ilubirin. The results follow similar trend for all the radiological parameters. The AGED values were higher than the world average (300 µSvy–1) set by UNSCEAR. The average lifetime cancer of mortality risk due to 40K, 232Th, and 238U was 2.09 × 10–3, 4.18 × 10–8, and 1.84 × 10–6, respectively, while that morbidity risks due to 40K, 232Th, and 238U were 3.07 × 10–3, 6.21 × 10–8, and 2.70 × 10–6, respectively. Radiological assessment however indicated that long-term exposure may pose an intrinsic health hazard.

Specific Activities and Annual Effective Dose of Natural Radionuclides Due to the Intake of Some Types of Sugar Available in Baghdad Markets

In this research the specific activity of natural radionuclides 226Ra, 232Th and 40K were determined by sodium iodide enhanced by thallium NaI (Tl) detector and assessed the annual effective dose in Beladi, Aldar, Alusraa, Alkhaleej and Aletehaad which are available in Baghdad markets. The specific activity of 40K has the greater value in all the types which is in the range of allowed levels globally that suggested by UNSCEAR. The mean value of annual effective doses was 0.198, 0.094 and 0.098 mSv/y for 226Ra, 232Th and 40K respectively.

Specific Activities of Natural Radionuclides and Annual Effective Dose Due to the Intake of Some Types of Children Powdered Milk Available in Baghdad Markets

In this research the specific activity of natural radionuclides 226Ra, 232Th and 40K were determined by sodium iodide enhanced by thallium NaI(TI) detector and assessed the annual effective dose in Dielac 1 and 2 and Nactalia 1 and 2 for children of less than 1 year which are available in Baghdad markets. The specific activity of 40K has the greater value in all the types which is in the range of allowed levels globally that suggested by UNSCEAR. The mean value of annual effective doses were 2.92, 4.005 and 1.6325 mSv/y for 226Ra, 232Th and 40K respectively.

Specific Activity and Radioactive Contour Maps of Natural (<sup>40</sup>K, <sup>226</sup>Ra and <sup>232</sup>Th) and Anthropogenic (<sup>137</sup>Cs) Radionuclides in Surface Soil Samples from Phang Nga Province, Thailand

The specific activity of the natural (40K, 226Ra and 232Th) and anthropogenic (137Cs) radionuclides have been studied and evaluated for 97 surface soil samples collected from 7 districts of Phang Nga province in the south of Thailand. High-purity germanium (HPGe) detector and gamma ray spectrometry analysis system were employed to measure and analyze the experimental results. It was found that, the ranges of specific activities of 40K, 226Ra, 232Th and 137Cs in surface soil samples are 251.50 – 15740.34, 15.21 – 791.42, 18.14 – 854.34 and < 0.33 – 16.91 Bq/kg with average values are 2886.77 ± 225.93, 165.71 ± 8.45, 160.36 ± 7.93 and 5.76 ± 2.49 Bq/kg, respectively. The results were also compared with some research data in national and global radioactivity measurement and evaluations. Furthermore, the radiological hazards of Phang Nga province were calculated through the radium equivalent activity (Raeq), the external hazard index (Hex), the gamma absorbed dose rate (D) and the annual effective dose rate (AEDout) and also compared with research data in the south of Thailand and the safety limits recommended values by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Moreover, the radioactive contour maps of the natural (40K, 226Ra and 232Th) and anthropogenic (137Cs) radionuclides have been also created for the investigated area.

Predicting Concrete Roadway Contribution to Gamma-Ray Background in Radiation Portal Monitor Systems

The collapse of the Soviet Union ushered in an era of interest in the security of the radiological and nuclear material holdings of the Russian Federation and other countries of the Former Soviet Union. Additionally, the increasing sophistication of international criminal and terrorist organizations highlighted the need to secure these materials and prevent them from being smuggled from their point of origin and across international boundaries. To combat the growing threat of radiological and nuclear smuggling, radiation portal monitors (RPMs) are deployed at ports of entry (POEs) around the world to passively detect gamma and neutron radiation signatures from cargo and pedestrian traffic. In some locations, RPMs are reporting abnormally high gamma-ray background count rates, a situation that has been attributed, in part, to the building materials surrounding the RPMs. The primary objective of this work was to determine the impact of different types of concrete on the gamma-ray background readings in a particular RPM. Secondary objectives include developing an adaptable model to estimate the gamma-ray background contribution from any composition of concrete in any RPM configuration and determining the elemental composition of different concrete samples through neutron activation analysis (NAA) techniques. The specific activities of 40K and isotopes from the 238U and 232Th decay series were determined with a high-purity germanium detector and computer-generated calibration files. Through NAA, 34 elemental compositions were determined for six concrete samples from three different parent slabs. The total weight percentages determined were 84% to 100% of the total mass of the samples. The Monte Carlo N-Particle (MCNP) transport code was used to simulate the RPM response to the different concrete slabs. The MCNP model was validated by comparing actual and simulated detector responses to 137Cs check sources of varying strengths. For all validation cases, the MCNP estimates were 6% to 16% less than the value obtained from the actual RPM data. This work shows that it is possible to estimate the gamma-ray response of an RPM to the underlying concrete roadway. Knowing the amount of this contribution will allow RPM customers to choose suitable foundation materials before installation and accurately set alarm thresholds. This could ultimately increase the ability of RPMs to detect radiation at POEs, thereby increasing the probability of a seizure of smuggled radiological and nuclear materials.

INVESTIGATION AND ASSESSMENT OF 40K ACCUMULATION IN THE SEGMENTS OF AN ORDINARY CARROT (DAUCUS CAROTA L.) AND RED BEET (BETA VULGARIS L.) / 40K KAUPIMOSI PAPRASTOSIOS MORKOS (DAUCUS CAROTA L.) IR RAUDONOJO BUROKĖLIO (BETA VULGARIS L.) SEGMENTUOSE TYRIMAS IR VERTINIMAS

The article deals with an alteration in specific activity and transfer factor of naturally occurring radionuclide 40K from soil with a loamy structure to the segments of root vegetables – an ordinary carrot (Daucus carota L.) and red beet (Beta vulgaris L.). The paper establishes the specific activity of 40K in soil and vegetable segments and evaluates transfer factors (TF). The obtained data show that the transfer factor of naturally occurring radionuclide 40K from soil to the segments of the ordinary carrot (Daucus carota L.) varied from 0,28 to 0,99 while that of the red beet (Beta vulgaris L.) – from 0,53 to 0,96. The results of the study could be used for estimating 40K transfer in the system “soil-plant” and accumulation of radionuclide in composting garden waste. Santrauka Straipsnyje nagrinėjama gamtinės kilmės radionuklido 40K savitojo aktyvumo ir pernašos faktoriaus kaita iš turinčių priemolio struktūrą dirvožemių į šakniavaisinių daržovių – paprastųjų morkų (Daucus carota L.) ir raudonųjų burokėlių (Beta vulgaris L.) – segmentus. Nustatytas savitasis 40K aktyvumas dirvožemyje ir daržovių segmentuose, įvertinti pernašos (PF) faktoriai. Gauti duomenys rodo, kad gamtinės kilmės radionuklido 40K pernašos faktorius iš dirvožemio į paprastosios morkos (Daucus carota L.) segmentus kito nuo 0,28 iki 0,99, o į raudonojo burokėlio (Beta vulgaris L.) – nuo 0,53 iki 0,96. Remiantis eksperimentinių tyrimų duomenimis bei atsižvelgiant į vykdomos veiklos radioaktyviąją dirvožemio užtaršą, galima įvertinti 40K pernašą dirvožemis-augalas sistemoje bei kaupimąsi daržininkystės atliekose.

INVESTIGATION OF HEAVY METAL AND RADIONUCLIDE DISTRIBUTION IN SILT OF LAKE DIDŽIULIS / SUNKIŲJŲ METALŲ IR RADIONUKLIDŲ PASISKIRSTYMO DIDŽIULIO EŽERO DUMBLE TYRIMAS / ИССЛЕДОВАНИЕ РАСПРЕДЕЛЕНИЯ ТЯЖЕЛЫХ МЕТАЛЛОВ И РАДИОНУКЛИДОВ В ИЛЕ ОЗЕРА «ДИДЖУЛИС»

The article deals with research of the ecological situation in Lake Didžiulis, located nearby the highway Vilnius–Kaunas (Trakai District); the most polluted locations in the lake were identified. Research of heavy metals (HM) and radionuclides in the lake silt is described. To research HM concentrations and the specific activities of radionuclides, the samples were collected from 12 bores in the most typical locations of the lake. The estimated HM concentrations in the silt of Lake Didžiulis vary within a wide range: Cr from 6.9 to 45.2 mg/kg, Ni from 20.4 to 55.7 mg/kg, Mn from 236 to 1362 mg/kg, Cu from 7.1 to 80.9 mg/kg, Pb from 24.4 to 87.8 mg/kg, Zn from 13.0 to 75.8 mg/kg. The HM concentrations in the lake silt do not exceed the maximum allowed concentrations (MAC) in the soil, whereas the concentrations of manganese, copper and lead in some samples are close to MAC. The counted specific activities of 40K fluctuate from 46 Bq/kg to 415 Bq/kg in the upper level silt and from 125 Bq/kg to 482 Bq/kg in the silt, which is found near the mineral soil. The specific activities of other radionuclides at the said depths of the silt range as follows: 226Ra from 23 Bq/kg to 85 Bq/kg and from 28 Bq/kg to 93 Bq/kg, 227Ac from 2.1 Bq/kg to17.0 Bq/kg and from 7.3 Bq/kg to 23.0 Bq/kg, whereas artificial 137Cs from <0.6 Bq/kg to17.6 Bq/kg and from <0.5 Bq/kg to 12 Bq/kg. Santrauka Straipsnyje nagrinėjama Didžiulio ežero šalia greitkelio Vilnius – Kaunas (Trakų raj.) ekologinė būklė, nustatytos ežero vietos, kur buvusi didžiausia tarša. Aptariami atlikti sunkiųjų metalų (SM) bei radionuklidų koncentracijų ežero dumble tyrimai. SM koncentracijoms ir radionuklidų savitiesiems aktyvumams tirti ėminiai buvo imti iš 12 gręžinių, parinktų būdingiausiose ežero vietose. Didžiulio ežero dumble nustatytas gana platus SM koncentracijų intervalas: Cr – 6,9– 45,2 mg/kg, Ni – 20,4–55,7 mg/kg, Mn – 236–1362 mg/kg, Cu – 7,1–80,9 mg/kg, Pb – 24,4–87,8 mg/kg, Zn – 13,0– 75,8 mg/kg. SM koncentracijos ežero dumble neviršija didžiausių leidžiamųjų koncentracijų (DLK) dirvožemyje, tačiau kai kuriuose bandiniuose mangano, vario ir švino koncentracijos yra artimos DLK. Nustatytieji 40K savitieji aktyvumai svyruoja nuo 46 Bq/kg iki 415 Bq/kg paviršiniame dumble ir nuo 125 Bq/kg iki 482 Bq/kg esančiame arti mineralinio grunto. Kitų radionuklidų savitieji aktyvumai tuose dumblo gyliuose svyruoja taip: 226Ra – nuo 23 Bq/kg iki 85 Bq/kg ir nuo 28 Bq/kg iki 93 Bq/kg, 227Ac – nuo 2,1 Bq/kg iki 17,0 Bq/kg ir nuo 7,3 Bq/kg iki 23,0 Bq/kg, o dirbtinės kilmės 137Cs – nuo <0,6 Bq/kg iki 17,6 Bq/kg ir nuo <0,5 Bq/kg iki 12 Bq/kg. Резюме Анализируется экологическoe состояние озера «Диджулис», которое находится возле магистральной дороги Вильнюс−Каунас (Тракайский район), идентифицируются места с наибольшим загрязнением, анализируютсярезультаты исследований тяжелых металлов (ТМ) и радионуклидов в иле. Для исследования концентраций ТМ испецифических активностей радионуклидов пробы ила были взяты из 12 скважин, подобранных в характерныхместах озера. Концентрации ТМ в иле озера «Диджулис» менялись в довольно широких интервалах: Cr – от6,9 мг/кг до 45,2 мг/кг, Ni − от 20,4 мг/кг до 55,7 мг/кг, Mn − от 236 мг/кг до 1362 мг/кг, Сu −от 7,1 мг/кг до 80,9 мг/кг, Pb − от 24,4 мг/кг до 87,8 мг/кг, Zn − от 13,0 мг/кг до 75,8 мг/кг. Концентрации ТМ, находящихся в илеозера, не превышали предельно допустимых концентраций (ПДК) в почве, однако в некоторых пробах концентрации марганца, меди и свинца были близки к ПДК. Специфическая активность 40K меняется от 46 Бк/кг до 415 Бк/кг на поверхности слоя ила и от 125 Бк/кг до 482 Бк/кг вблизи минерального грунта. Специфическиеактивности других радионуклидов на определенных глубинах ила меняются таким образом: 226Ra − от 23 Бк/кг до 85 Бк/кг и от 28 Бк/кг до 93 Бк/кг, 227Ac− от 2,1 Бк/кг до 17,0 Бк/кг и от 7,3 Бк/кг до 23,0 Бк/кг, а радионуклидов искусственного происхождения: 137Cs − от <0,6 Бк/кг до 17,6 Бк/кг и от < 0,5 Бк/кг до 12 Бк/кг.

Correlation of radioactivity measurements, air kerma rates and geological features of Sicily

Sicily, the largest Mediterranean island (with an extension of about 25 000 km 2 ), exhibits a very wide variety of lithologies, ranging from sedimentary to metamorphic and volcanic rocks. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied to air kerma values measured by thermoluminescent dosimetry in several sites and to data of radionuclide concentrations, geochemical and mineralogical features of rocks and soils sampled in 29 sites of Sicily to point out similarities among different lithologies. The study was devoted to find multiple correlations and allow a better classification of Sicilian lithotypes. Samples of rocks and soils have been analyzed by X-ray fluorescence (XRF), X-ray diffractometry (XRD), and gamma-ray spectrometry. Major element concentrations, mineralogical data, along with specific activities of 40K, 238U, and 232Th natural radionuclides, have been determined in several samples. Geochemical, mineralogical and petrographic features are in good agreement with radiometric data. A survey was also performed to measure air kerma in outdoor environment using thermoluminescent dosimeters. The measured values were compared with the predicted levels computed from the radioisotope concentrations present in rock and soil samples. Moreover, collected data can be used to evaluate the health impact of the natural radioactivity on the population.