Levels of cesium radionuclides in mosses in the eastern Black Sea area of Turkey

Moss samples collected from the eastern Black Sea about 6.5 years after the Chernobyl accident have been analyzed for radiocesium activity.¹³⁴Cs activity was also detected in all the samples beside¹³⁷Cs radionuclide. The levels of total cesium activity in the mosses proved that the coastal zone in the eastern Black Sea region was highly contaminated.     

Chernobyl radioactivity in Turkish tea and its possible health consequences

Like several other European countries, Turkey has been affected by the radioactive clouds arising from the Chemobyl reactor accident. There were two major fronts. The first one affected the western parts of Turkey, namely Thrace, Istanbul and Western Black Sea coast, starting from April 30th 1986. The second cloud affected the Eastern Black Sea coast at the beginning of May 1986. In both regions the clouds left their radioactive content with the heavy rains. Eastern Sea coast is one of the regions receiving highest volume of rainfall almost all year round. However, after the accident, the rains loaded with radioactive contaminants felt just before the tea collection period and the contaminated tea leaves were collected without finding a chance for cleaning with following rains. All of the tea consumed by Turkish people grows on a very narrow coastal line along the Eastern Black Sea. In this study, the results of radioactivity measurement on Turkish tea are summarized. Although there were other affected products in the region, e.g., hazelnuts, tobacco, vegetables, their level of contamination and yearly consumption rates were not as significant as tea. Tea is the major hot beverage consumed by Turkish people of all ages, but unfortunately it turned out to be one of the heavily contaminated products of Turkey. The effect of brewing and rinsing with hot water on tea were also investigated in the present work. The dose estimates from the tea consumption was done following a different approach than previous studies. Instead of using the radioactivity data obtained by measuring only limited number of contaminated tea samples in our laboratories, the data reported by the Turkish Atomic Energy Agency Authority covering all the tea product of 1986 were used for dose estimates. In addition the collective effective dose equivalent in Turkey was estimated. Although in this study contamination only in one product, namely tea, was discussed, it turned out to be important as it was consumed by large populations in Turkey, so contributed to the doses significantly. Precautions to be taken were summarized, one simple precaution rinsing of tea before brewing was sufficient to remove half of the contamination from tea without any drawbacks.Dedicated to the memory of late Olcay Birgül.     

Energy dispersive X-ray fluorescence and neutron activation analysis of surficial sediments of the Sea of Marmara and the Black Sea around Istanbul

Surficial sediment samples, collected from 27 sampling sites of the Sea of Marmara and the Black Sea nearby Istanbul area in 1996 and 1999 years, were analyzed quantitatively for some heavy metals and some other elements by using radioisotope excited energy dispersive X-ray fluorescence (EDXRF). The U and Th concentrations of the samples were determined by instrumental neutron activation (INAA). The results were compared with those from other contaminated and uncontaminated sedimentary materials. It is found that some elemental concentrations of the Sea of Marmara and the Black Sea sediments are comparable with those in most other sea sediments in the vicinity of densely populated regions.     

Levels of cesium radionuclides in lichens and mosses from the province of Ordu in the Eastern Black Sea area of Turkey

Chemobyl nuclear power plant accident in Ukraine in April 26, 1986 has affected Scandinavia and European countries, the Balkans and the northside of Turkey. Radioactive clouds depending on meteorological conditions had contaminated soil surface and flora in the region of Thrace and the seaside of the Black sea. This study has been done on mosses and lichens in which radioactive isotopes can live for a long time. These specimens have been collected in various regions of Ordu located in the Eastern Black Sea region of Turkey. On the basis of the results of this study the geographic distribution of pollution on the flora has been done.     

Chernobyl radioactivity on the Black Sea coast of Turkey

After the Chernobyl reactor accident, Eastern Black Sea coast was one of the heavily contaminated regions of Turkey. Clouds loaded with radioactive isotopes arrived the region on May 1986 and emptied their contents with the heavy rains that are frequently seen in the region. In order to asses the current level of contamination, several different samples, moss, lichen, litter, surface soil and soil cores were collected on August 1994. Samples were brought to the laboratory and their moisture, pH and organic matter contents were determined. Gamma-ray spectra of the samples were collected with a HpGe detector. (137)Cs was the major isotope observed. Activity of most litter samples were below 1000 Bq/kg, while most of the moss samples had activities below 5000 Bq/kg, there were a few with higher (137)Cs activities. Surface soil samples generally had activities less than 2000 Bq/kg and depth profiles of cesium activities in the soil cores showed regional variations.     

Chernobyl radioactivity on the Black Sea coast of Turkey

After the Chernobyl reactor accident, Eastern Black Sea coast was one of the heavily contaminated regions of Turkey. Clouds loaded with radioactive isotopes arrived the region on May 1986 and emptied their contents with the heavy rains that are frequently seen in the region. In order to asses the current level of contamination, several different samples, moss, lichen, litter, surface soil and soil cores were collected on August 1994. Samples were brought to the laboratory and their moisture, pH and organic matter contents were determined. Gamma-ray spectra of the samples were collected with a HpGe detector. ¹³⁷Cs was the major isotope observed. Activity of most litter samples were below 1000 Bq/kg, while most of the moss samples had activities below 5000 Bq/kg, there were a few with higher ¹³⁷Cs activities. Surface soil samples generally had activities less than 2000 Bq/kg and depth profiles of cesium activities in the soil cores showed regional variations.     

Determination of fission-products and actinides in the Black Sea following the Cherynobyl accident

Radiochemical procedures are discussed for the isolation and determination of a suite of radionuclides in samples from the Black Sea following their input from the Chernobyl reactor accident. The samples analyzed include discrete water samples and both suspended and dissolved phases collected by in-situ chemisorption techniques. The radiochemical scheme permits the separation and analysis of¹³⁴Cs,¹³⁷Cs,⁹⁰Sr,¹⁴⁴Ce,¹⁴⁷Pm,¹⁰⁶Ru,²³⁹Pu,²⁴⁰Pu, and in some instances²⁴²Cm,²³⁸Pu, and²⁴¹Am. The detection techniques employed include various instrumental gamma spectrometric methods, low-level beta counting, alpha spectrometry, and mass spectrometry.The method's developments are described and data are presented on some representative samples from the Black Sea. The sensitivity of the analysis for the various nuclides and sample types is summarized and questions of radiochemical interferences are addressed.     

Activity concentrations of selected artificial and natural radionuclides in water and sediment samples from the North Western Black Sea, 1999

Radioactive concentrations of several artificial and natural radionuclides were determined in water and sediment samples collected from various locations in the NW Black Sea in December 1999. For water samples, ⁹⁰Sr and ¹³⁷Cs activity concentrations were of approximately 11 mBq/l and 26.3-41.2 mBq/l, respectively. The concentration of tritium ranged from 7 to 24 T.U. In sediment samples, maximum concentrations of ¹³⁷Cs, ^239+240Pu and ²⁴¹Am were found of 128±6 Bq·kg^-1, 1.8±0.1 Bq·kg^-1 and 0.05±0.04 Bq·kg^-1, respectively. For U and Th radionuclides, the concentrations ranged from 20-80 Bq·kg^-1 and 30-50 Bq·kg^-1, respectively. The results were consistent with those reported in earlier research for the Black Sea. This revised version was published online in July 2006 with corrections to the Cover Date.     

137Cs in Biota and Sediment Samples from Turkish Coast of the Black Sea, 1997–1998

During the periods of 1997–1998, macroalgae, sea snail, mussel, fish and sediment samples were collected from different stations at Turkish Black Sea coast in order to determine activity levels of ¹³⁷Cs radionuclide. ¹³⁷Cs activity in the tested algae species and in soft parts of mussel and sea snail, were found to be below the lower limit of detection. On the other hand, the ¹³⁷Cs concentration in muscle tissue of the sea snail samples were found from 6±2 to 19±7 Bq·kg^–1 dry weight. The range of the ¹³⁷Cs concentration in anchovy fish muscles were found between 4±2 – 10±5 Bq·kg^–1 dry weight. The ¹³⁷Cs concentration in the whiting fish muscle was found below the lower limit of detection. However, this activity found in shad fish muscle to be 25±10 Bq·kg^–1 dry weight. The concentrationsof the ¹³⁷Cs activity in the sediment samples proved that the eastern region of the Black Sea was affected by Chernobyl at a very high degree compared with the western part. The measured ²³⁸U, ²³²Th and ⁴⁰K concentrations in sediment samples are within the range of the cited values in the previous works at the Turkish Black Sea coast.     

Quantitative analysis of sea-bed sediments from Eastern Black Sea by EDXRF spectrometry

Sea-bed sediments from Eastern Black Sea have been analyzed for their Fe, Ba and Sr contents using the methods of standard addition and energy dispersive X-ray fluorescence (EDXRF). Samples were prepared from powder sifted by a 200 mesh sieve. An annular 100 mCi²⁴¹Am radioactive source emitting 59.543 keV photons was used for excitation and a Ge(Li) detector, which has a 190 eV FWHM for 5.9 keV photons was used for intensity measurements. 2048 channels of the MCA are employed for 20 or 30 min. Dried and ground sea-bed sediments are found to contain 2.95–7.50% Fe, 0.032–0.268% Ba and about 73–273 ppm Sr. These results agree with those obtained via atomic absorption methods.     

Sediment sample preparation for the determination of Pu and Am isotopes

Summary Sediment samples from the Romanian sector of the Danube River and the Black Sea coast were analyzed for Pu and Am. Three different ways of bringing the samples into solution were tested: acid attack, microwave digestion and alkaline fusion. A conventional anion-exchange resin was used to separate plutonium from other radionuclides and several variants were tried to improve the separation of americium. The preparation of thin sources for alpha-spectrometry was tested through electrodeposition and coprecipitation with Nd(III). Discussion and recommendations for the dissolution step, the americium separation and preparation of alpha sources are made.     

Natural depuration rate and concentration of cesium-137 radionuclide in Black Sea macro algae

Cesium-137 concentrations in red, brown and green algae have been studied for the calculation of natural depuration rates. The algae species were collected from the same population of the Black Sea stations during the period of 1986–1995. The natural depuration rates are estimated as biological half-lives. The pattern of depuration results represented by a single component for each algae division. The biological half-lives of¹³⁷Cs in red (Phyllophora nervosa), green (Chaetomorpha linum) and brown (Cystoceira barbata) algae are estimated to be 18.5, 21.6 and 29.3 months, respectively.¹³⁷Cs and⁴⁰K activity levels and their ratios in algae species in two stations in Black Sea region of Turkey have been determined during the period of 1990–1995. The results showed that the Sinop region was more contaminated than the ile region on the Black Sea coast of Turkey from the Chernobyl accident.     

Tritium activity concentration along the Western shore of the Black Sea

The Black Sea tritium level was investigated in 33 places southward the Danube Delta covering about 360 km of the Black Sea Western Shore. Both surface (10 cm depth) and bottom (up to 20 m depth) water samples were collected. In the close vicinity of Danube Delta, the tritium activity concentration in the surface water was around 28 TU, which is almost the same as that of the Danube River waters, but it decreased to about 5 TU in the bottom water. This discrepancy slowly diminished wherein at about 120 km southward, the tritium content in both surface and bottom water reached almost the same constant value of 6.5 ± 2.3 TU. This value, about two and a half times smaller than that reported 17 years ago, remained almost unchanged for the last 240 km of shore up to the Turkish border.     

Mössbauer and X-ray study of natural magnetite sands

Black sands originating from north, west and south seaside strips of the Bay of Burgas, Black Sea, were investigated. It was found that these sands are martitized magnetites. Their composition involves mixtures of nonstoichiometric magnetite and maghemite or stoichiometric magnetite and hematite.     

Chernobyl-derived radiocesium in mosses in the Black Sea area

Radiocesium (¹³⁴Cs and¹³⁷Cs) activity levels in mosses from the Black Sea area, northern Turkey, are reported following the Chernobyl accident during the period of 1989–1991. The cesium radionuclides were detected and measured in all the samples but other longlived radionuclides such as¹⁴⁴Ce and¹⁰⁶Ru were measured in only one sample. The present data support the fact that radioactivity monitoring in mosses can be useful to determine the lasting effect of radioactive contamination.     

Information Obtained by Three Different Methods of U and Th Determination in Sediment and Algae Samples from the Romanian Sector of the Danube River and the Black Sea Coast

The concentration distributions of U and Th nuclides in some sediment and algae samples from the Romanian sector of the Danube river and the Black Sea coast are presented. Data are obtained by neutron-induced fission activation analysis, epithermal instrumental neutron activation analysis and radiochemical separation using tracers followed by -spectrometry counting of stainless steel discs after electrodeposition. The analysing time, the working steps, the necessary equipment, the information and quality of the obtained results are discussed.     

Role of mineralogical structure of sediments in accumulation of radionuclides and trace elements

Similar distributions for ²³⁸U, ²³²Th, ²²⁶Ra, ²¹⁰Po, ^238,239,240Pu, ¹³⁷Cs and trace elements were obtained in sediment samples collected along the Romanian sector of the Danube River and the Black Sea coast during 1994. The radionuclide and trace element accumulation in the investigated samples is discussed with respect to their geochemical behavior and the mineralogical structure of the samples. The latter, investigated by X-ray diffraction and cation exchange capacity of the same samples, proves to be an important factor in the selection of sampling sites for monitoring the pollution of river basins and the sea.     

Polonium concentration distribution in bed load sediment samples along the Romanian sector of the Danube river and the Black Sea coast

The concentrations of²¹⁰Po have been determined in 12 sediment samples collected from the bed of the Romanian Danube river and the Black Sea coast during June–September 1994. After the sample preparation and the addition of the²⁰⁸Po tracer, polonium was coprecipitated with manganese dioxide, the precipitate was dissolved in hydrochloric acid and the polonium isotopes deposited on silver planchettes were counted by -spectrometry. The resolution of the subsequent -spectra was typically 40 to 60 keV full-width-half-maximum with 450 mm² silicon surface-barrier detectors at 30% counting efficiency. The procedure is quite fast, giving chemical yields between 60 and 80%. The²¹⁰Po concentrations range between 5 and 73 Bq kg^–1 dry, showing for the first time the polonium contamination distribution along the Romanian sector of the Danube river and the Black Sea coast.     

Plutonium concentration distribution in bed load sediment samples along the Romanian sector of the Danube river and the Black Sea coast

The concentrations of²³⁸Pu and^{239, 240}Pu were determined in 12 sediment samples collected from the bed of the Romanian Danube river and Black Sea coast during June–September 1994. After the sample material has been properly prepared and²⁴²Pu tracer added, plutonium was separated from americium and curium by anion exchange. After electrodeposition on stainless steel discs the elements were counted with an -spectrometry system with silicon surface-barrier detectors. The^{239, 240}Pu concentrations range between 150 and 800 mBq kg^–1 dry, while the²³⁸Pu concentrations rise up to max 150 mBq kg^–1 dry. Although the chemical yields are rather low (51%) we appreciate the results as valuable since they report for the first time the distribution of the plutonium contamination along the Danube river and the Black Sea coast-Romanian sector.     

Artificial radioactive contamination of sediments along the Romanian sector of the Danube river and the Black Sea coast

The concentrations of⁹⁰Sr,²³⁸Pu,^239,240Pu and²⁴¹Am were determined in 12 sediment samples, collected from the bed of the Romanian sector of the Danube river and the Black Sea coast during 1996–1997. The samples were dissolved using a microwave digestion technique which left the refractory part of the samples undissolved. Part of the samples were also dissolved totally by alkaline fusion. The results obtained after radiochemical separations and measurement of the radionuclides by the two dissolution methods were compared recommending the optimum method. The radioactive contamination of the investigated sector in 1996–1997 is compared with the results obtained for the same locations in 1994–1995 reported in previous papers.