G. Yener

Trace metals and 210Po (210Pb) concentrations in mussels (Mytilus galloprovincialis) consumed at western Anatolia.

The mussels (Mytilus galloprovincialis) have been evaluated for their bioavailability as biomonitors of trace and toxic elements in coastal water of western Anatolia. The levels of Fe, Cu, Zn, Pb, Br and Sr in the edible part of mussels were determined using X-ray fluorescence method during the period of September 1999-July 2000. Distribution of 210Po and 210Pb activities were measured by radiometric methods and their ratios were calculated. The activity concentrations of 210Po and 210Pb were found to vary between 52 +/- 6-1,344 +/- 108 and 6 +/- 2-167 +/- 10 Bqkg(-1) dry wt, respectively. The highest values for 210Po and 210Pb were measured in Foca mussels and also observed the highest Fe, Zn and Br concentrations in the same species. 210Po/210Pb activity ratio were derived as between 3.1 and 25.0.

Study of spontaneous deposition of 210Po on various metals and application for activity assessment in cigarette smoke

Abstract 210Po in environmental samples has been accumulated on various metals using the chemical electrodeposition technique. The 210Po was deposited spontaneously on metal discs after decomposition of the sample in HCl acid and then measured using a ZnS(Ag)α-particle detector. Silver was observed to have the highest deposition efficiency when 210Po deposition on different metals was studied. Copper discs were used in the application of activity assessment in cigarette smoke as this is more available and more economical although silver has a higher efficiency than that of other materials examined. The technique is applied for the analysis of 210Po in tobacco, ash and butt for several brands of imported and domestic cigarettes smoked in Turkey.

Lichens and mosses for correlation between trace elements and 210Po in the areas near coal-fired power plant at Yatağan, Turkey

The lichensRhizoplaca melanophthalma, Cladonia convoluta, Cladonia pyxidata and the mossesGrimmia pulvinata,Hypnum cupressiforme were analyzed for Pb, Cr, Cd, Co, Ni, Mn, Cu, Zn and Fe using atomic absorption spectrophotometry over a wide area around a coal-fired power plant located in Yatağan. The results were compared with the 210Po concentrations previously measured in the same samples. Correlations between 210Po and trace elements for different moss and lichen species of the same localization and for different localizations for the same species were also studied. In general trace element concentrations do not show significant differences from site to site for all species except Mn in Hypnum cupressiforme and 210Po in Grimmia pulvinata. To discuss the 210Pb level and sources in indicator plants analyzed, also radium contents of surface soil at each sampling station was measured and compared with the average values for similar soil types in the literature.

Activity concentration of caesium-137 in agricultural soils.

In this study, we measured 137Cs activity concentrations in the soil samples taken from agricultural lands in the Buyuk Menderes Basin in Turkey in 1997 and 1998. The soil samples were collected from 42 sites in this Basin. The activity concentration of 137Cs was found to range between 2.81+/-0.17 Bq.kg(-1) and 20.75+/-0.29 Bq.kg(-1). The effect of organic matter, clay, silt and sand contents and pH of the soil on the relative adsorption of the 137Cs on the soil surface were also studied.

Accumulation rates and sediment deposition in the Gökova Bay in Aegean Sea Turkish Coast.

Sediment accumulation rates were estimated from the vertical distribution of excess 210Pb in sediment cores collected at six stations in the Gökova Bay near the heavily industrialized Turkish Coastal zone of the Aegean Sea. Total 210Pb was determined by measuring 210Po activities. The sediment accumulation rates were calculated to vary from 0.32+/-0.01 cm yr(-1) (0.17 +/- 0.01 g cm(-2) yr(-1)) to 1.92 +/- 0.20 cm yr(-1) (1.13 +/- 0.10 g cm(-2) yr(-1)). The unsupported 210Pb flux was calculated from the accumulated dry matter of the examined slices and their unsupported 210Pb concentrations. The flux of unsupported 210Pb varies between 62 +/- 5 and 105 +/- 8 Bq m(-2) yr(-1). The average depositional flux was found to be considerably higher for cores from the Mediterranean.

LOW ENERGY SCINTILLATION SPECTROMETRY FOR DIRECT DETERMINATIONS OF 238U AND 210PB IN COAL AND ASH SAMPLES

Abstract Fly ash, bottom ash and coal samples from a power plant operating with uranifereous coal were analyzed for their 210Pb and 238U contents by means of a technique developed in low energy scintillation γ-spectrometry. Results were compared with the 226Ra 9eU) contents determined with high energy spectrometry. The measurements of 238U, 234Th and 210Pb contents have shown significant departure from radioactive equilibrium indicating that the coal was mined from young deposits. The redistribution of radionuclides in the ash was also investigated and the enrichment factors were determined.

Radon Levels in New and Old Buildings

222Radon is a colorless, odorless, tasteless, radioactive gas that occurs naturally in soil, rocks, underground water, and air. It is produced by the natural breakdown of 226Radium in soil and rocks. In outdoor air, radon is usually presents at such low levels that there is very little risk. However, when radon enters a building, it and its decay products can accumulate to high concentrations. Radon, itself, naturally breaks down and forms radioactive decay products. As one breathes, the radon decay products can become trapped in lungs. As these decay products break down further, they release small bursts of energy which can damage lung tissue and lead to lung cancer. In this study, the indoor radon concentrations of some buildings of different ages in Bornoya town of Izmir were determined. Lucas Cells and nuclear track detectors (CR-39) were used for the measurements of 222Rn levels in the rooms of 15, 25 and 150 years old buildings. The annual effective dose equivalent from 222Rn was calculated in these buildings.

Estimation of sediment accumulation rates using naturally occuring 210Pb models in Gülbahçe Bay, Aegean Sea, Turkey

The sediment chronology was determined using Lead-210 (²¹⁰Pb) dating method in Gülbahçe Bay. Sediment cores were obtained using gravity core sampler from hydrothermal area and also from reference point and surfical distribution of Polonium-210 (²¹⁰Pb) was investigated in the study area. The average of surfical concentration of ²¹⁰Po was found as 175.25 ± 3.80 Bq kg⁻¹ in the hydrothermal area which was higher than the reference point value of 133.20 ± 3.30 Bq kg⁻¹. Sedimentation rates in Core reference point (RN) displayed an increase till the year 1942 and a decrease afterwards, sedimentation rates in any core from hydrothermal area have not exhibited any continuous increase or decrease. The ²¹⁰Pb fluxes measured from core inventories are close to each other. Average enrichment factors for Cu, Cd, Sr, Zn, Cr vary between 20.35 and 12.18 indicating that the sediments have been contaminated with these metals in the reference point. Maximum enrichment factor values for Cr, Cu, Zn, Ba, Sr, Ni, Co vary between 22.91 and 11.42, implying that the sediments in hydrothermal area have been contaminated with these metals.

Direct measurement of U-238 and disequilibrium state in geological samples by low energy scintillation gamma spectroscopy

Abstract A method has been developed to determine the state of disequilibrium and uranium content in geological samples using low energy gamma scintillation spectrometry. Ore standards in radioactive equilibrium were prepared in different concentrations and their low energy spectra were compared with those of chemical uranium standards of the same concentrations. The standards were analysed carefully for their U contents using X-ray fluorescence and high resolution gamma spectrometers. Counts of the complex peak under which 63 keV and 93 keV photopeaks take place in ore spectra were compared with the counts in corresponding channels of chemical uranium spectra. For standards in equilibrium it was found that (26 ± 2)% of the counts under complex peak came from Th-234 and also there was a constant relation between Th-234 (63 keV and 93 keV) and Pb-210 (47 keV) counts. The technique was applied to the geological samples for which eU concentrations had been measured previously by means of high energy gamma spectroscopy in the same laboratory.

Plutonium isotopes, 241Am and 137Cs activity concentrations in marine sediments of Gökova Bay, Aegean Turkish Coast

Samples of marine surface sediments of different grain sizes collected in Gökova, a small bay on the Aegean Turkish Coast, have been examined to measure alpha- and gamma-radioactivity. The purpose of this research is to define a baseline study of man-made radionuclides on sediments along Gökova Bay, using a combination of direct gamma-spectrometry, radiochemical separation and alpha spectrometry. The analysis of these samples revealed measurable quantities of some artificial radionuclides namely: 239+240Pu (from 0.13±0.017 to 0.85±0.15 Bq.kg–1). 137Cs, 241Am and 238Pu were identified at a very low level. Concentration ratios of 238Pu to 239+240Pu obtained seem to confirm that this artificial radioactivity is due mainly to Chernobyl accident.