Cs 137

The paper considers distribution of 137Cs concentrations in soils and atmospheric dry depositions by altitudinal belts of the Aragats mountain massif (Armenia). Undisturbed soil samples were collected at altitudes from 1000 to 3200 m. For the determination of geochemical variability two soil sampling campaigns were undertaken. Atmospheric dry depositions were sampled from five stations at 1100-3200 m onto organic fiber filters between June and December 2016. 137Cs activity was measured using an HPGe detector. Results indicated that 137Cs activity in soils and atmospheric dry depositions decrease as the absolute altitude decreases. The 50-year effective dose from exposure to 137Cs fallout varies with altitude from 0.007 to 1.42 mSv and does not exceed the maximum effective dose limit for the population of 1 mSv year-1.

Sediment variability increased from Mendall Marsh/Orland River b Penobscot estuary b Penobscot River. • Generally, sediment mixing was limited (maximum Db ranged from 3-6 cm 2 y-1 ; mixed layers of~1-3 cm). • A wide range in sediment accumulation rates was observed (0.10-1.85 cm y-1), and was expected. • Extensive lateral transport of sediment (and total Hg) was limited to parts of the Penobscot River. • Sediment (and Hg) accumulation in the Penobscot River was most random, focused inside meanders, and coves.

Mercury (Hg) was discharged in the late 1960s into the Penobscot River by a chlor-alkali production facility, HoltraChem. Using total Hg concentration profiles from 56 stations (58 sediment cores) in the Penobscot River (PBR), Mendall Marsh (MM), Orland River (OR) and Penobscot Estuary (ES), and sediment accumulation rates derived using detailed profiles of total Hg concentrations and radionuclide activities ((137)Cs, (239,240)Pu, (210)Pb), recovery from system-wide Hg pollution was assessed. Total Hg concentration profiles showed sharp maxima at depths attributed in time to a 1967 release date, and were divided into two sections: the first 21years (1967-1988; rapid recovery), and the recent 21years (1988-2009; slower recovery). The recent 21years of Hg input were used to estimate 'apparent' recovery rates, yielding exponentially decreasing total Hg concentrations. Apparent recovery half-times (T1/2=ln2/α) were calculated from an exponential fit of Hg(t)=Hg(t=21)∗exp(-α∗t)+H...

This work presents the distribution of radioactive caesium in several types of forest soil originating from the Lesisko reserve (Opole Province, Poland). Vertical distribution of 137 Cs isotope was determined in the profiles related to physicochemical properties of different types of soils and their location. Thickness of emerging genetic horizons, structure and morphology of soil profiles were determined. The highest 137 Cs activities were found in Of and A horizons. At the same time, there was a sudden drop of 137 Cs activity in mineral horizons of soil profiles. By analysis of caesium radioisotope content and its distribution in soil profiles significant correlations were observed between certain physicochemical properties (e.g. pH value, hydrolytic acidity, granulometric composition) of soils in selected forest habitats.

After the Fukushima Daiichi Nuclear Power Station accident, the distributions of sediment-associated radiocesium were investigated to evaluate the dispersion and accumulation of radiocesium in the reservoir field. To develop an analytical method for measuring the horizontal and vertical distributions of radiocesium on a wide scale, we obtained 253 gamma-ray spectra at the bottoms of 64 ponds in Fukushima during 2014-2016 by using a NaI(Tl) scintillation detector. For visualizing horizontal distribution, correlation between detector counting rate and radiocesium concentration of the bottom sediment was confirmed. In estimating vertical distribution, the depth profile of sediment-associated radiocesium was found to be correlated to the intensities of scattered and photo peaks. Good agreement was observed between the results of in situ spectrometry and core sampling. These results indicate that the developed method is suitable for understanding the behavior of radiocesium and determining whether decontamination of reservoirs is required.

Due to the radiocesium derived from the accident at Chernobyl in 1986 deposited on the soil, this study presents experimental data on Cs-137 activity concentrations in soil samples taken from agricultural land of Aegean Region in Turkey in 1997 and 1998. The activity of Cs-137 for these soil samples was found in the range between 0.92±0.15 Bq/kg and 20.75±0.29 Bq/kg. The distribution of Cs-137 in the soil can differ, being dependent on soil properties.

A database on238U,232Th,40K, and137Cs in surface soils was established to provide inputs for the assessment of the collective dose to the population of Vietnam and to support soil erosion studies using137Cs as a tracer. A total of 292 soil samples was taken from undisturbed sites across the territory and the concentrations of radionuclides were determined by gamma spectrometry method. The multiple regression of137Cs inventories against characteristics of sampling locations allowed us to establish the distribution of137Cs deposition density and its relationship with latitude and annual rainfall. The137Cs deposition density increases northward and varies from 178 Bq m–2to 1,920 Bq m–2. High rainfall areas in the northern and central parts of the country have received considerable137Cs inputs exceeding 600 Bq m–2, which is the maximum value that can be expected for Vietnam from the UNSCEAR global pattern. The mean activity concentrations of naturally occurring radionuclides238U,232Th, ...

Two sediment cores in Kuala Selangor estuary and Pantai Remis coastal area were obtained using gravity corer and then were analyzed using Alpha Spectrometry System. In order to estimate the sedimentation rate in the area, 210 Pb dating technique and Constant Rate & Supply (CRS) model were used. From the study, the vertical profile of 210 Pb shows a decreasing trend with depth and finally achieving a constant level. Based on the vertical profile of 210 Pb, activity of excess 210 Pb was obtained and was used to determine the sedimentation rate in the study area. Pantai Remis coastal area shows high sedimentation rate than Kuala Selangor estuary which may due to high sediment input in the area. Besides, the differences in sedimentation rate might be attributed to highly variable sedimentary and hydrodynamic conditions in the estuary and coastal area.

A database on238U,232Th,40K, and137Cs in surface soils was established to provide inputs for the assessment of the collective dose to the population of Vietnam and to support soil erosion studies using137Cs as a tracer. A total of 292 soil samples was taken from undisturbed sites across the territory and the concentrations of radionuclides were determined by gamma spectrometry method. The multiple regression of137Cs inventories against characteristics of sampling locations allowed us to establish the distribution of137Cs deposition density and its relationship with latitude and annual rainfall. The137Cs deposition density increases northward and varies from 178 Bq m–2to 1,920 Bq m–2. High rainfall areas in the northern and central parts of the country have received considerable137Cs inputs exceeding 600 Bq m–2, which is the maximum value that can be expected for Vietnam from the UNSCEAR global pattern. The mean activity concentrations of naturally occurring radionuclides238U,232Th, ...

Sediment deposition and accretion rates in a Virginia tidal freshwater marsh were measured to provide insight to the processes and time scales that are important for maintaining marsh surface elevation. Short-term sediment deposition rates (biweekly to monthly) measured using sediment collection tiles were spatially and temporally variable. Rates were greatest near a tidal creak and decreased along a transect extending toward the marsh interior. When integrated across the entire marsh, annual sediment deposition (as organic carbon) averaged 517 353 g C m 2 y 1 and was sufficient to balance the effects of existing relative sea level rise and marsh respiration rates. At the creekbank, the highest deposition rates were measured during summer although rates were relatively constant over time at the interior sites. Similar spatial and temporal patterns were obtained when deposition rates were calculated from 7 Be inventories (monthly time scale). Sediment inventories of 7 Be were greater than those supported atmospherically, indicating that the spatial patterns of sedimentation were not due to sediment erosion and redistribution within the marsh. Accretion rates calculated from 137 Cs (decadal scale) and 14 C dating (centuries to millennia) were substantially less than annual deposition rates, with a decrease in accretion rate with increasing time scale. Mineralization rates of recently deposited sediments (measured as O 2 consumption) indicated that sediment metabolism could potentially remove 30% of recently deposited carbon within one month of deposition. The metabolism of a labile sediment fraction could explain a portion of the observed decrease in accretion rate with increasing time scale, with the remainder due to periodic storm-induced erosion and historical variability in sediment deposition rates.

A record of the impacts of major hurricanes on sediment stratigraphy and composition in subtropical ecosystems has been preserved in the lower Everglades and Florida Bay. These impacts were observed in discontinuous layers of sediment that were identified from highresolution, vertical profiles of excess 210 Pb and 137 Cs. Discontinuities were found at different geographic locations and at two to three different depths in the sediment column; however, the layers were each deposited within time periods that corresponded with the passing of category 3-5 hurricanes during 1960, 1948 and 1935. A simple mass balance model for excess 210 Pb was used to show net changes of ± 20-100% in excess 210 Pb inventory that resulted from sediment disturbances of <1 to >22 cm. Abrupt shifts in sediment composition were often observed in hurricane-impacted layers. Ratios of organic (C/P) were four-to fivefold higher than normal in post-hurricane layers of sediment at open bay sites. These layers are phosphorus poor and seem to reflect preferential decomposition of organic P relative to organic C in association with hurricanes. The net effect is for major hurricanes to redistribute sediment, organic matter and nutrients.

The retention of strontium from solutions (concentration range 2 to 30 mg/l) by soils developed under arid conditions of Iran was investigated using a batch technique. Sr sorption characteristics a clayey and a silty clay loam soil were examined at room temperature and with 0.01M CaCl 2 as a background electrolyte. Sorption processes are found to show a Freundlich8type behavior. Results indicated the clay content and ionic strength play predominant role on sorption of Sr. At soil with high soluble cations (saline8sodic soil) less strontium was adsorbed at lower concentrations of strontium due to greater competition with other cations especially with soluble Ca and Mg. Electrical conductivity and ratio of soluble Ca and Mg to total soluble cations is important especially in soils with high EC and SAR.

In this study, 210 Pb(210 Po) activity concentrations in surface soils taken from cultivated lands in the Buyuk Menderes Basin in Aegean Region, Turkey were determined. The 210 Pb(210 Po) activity in soil varies from 0.013 to 0.135 Bq/g with a mean value of 0.041 Bq/g. Its distribution fitted close to normal curve. The mean annual effective dose equivalent was found to be 0.91 Sv/y. The data obtained were statistically evaluated to explain the 210 Pb(210 Po) distribution in the cultivated lands. The effect of organic matter, clay, silt, sand contents and pH of the soil on the relative adsorption of the 210 Pb(210 Po) on the surface soils was also studied.

Biodiversity includes three main concepts: genetic diversity, species diversity and ecosystem diversity. Species diversity: mountain ecosystems, alpine regions above the timberline, have to be rich in terms of plant compositions and plant species diversity. Richness and evenness are two main factors in measuring the diversity of a habitat. Richness takes into account individual species, while evenness contributes towards the relative abundance of each species. According to the results of this study, 52% of the total endemic plant taxa of the Kazda?? National Park is determined in the alpine regions and therefore the alpine zones, with their rich endemic and rare plant species, are important from the aspect of biodiversity and species conservation. In addition, this study describes the relation between environmental factors and plant species diversity and evenness.

The functional characteristics of forest soils in the mountainous regions in Bulgaria were assessed in order to obtain a better understanding of cesium distribution in soil. The aim of this paper is to describe the small-scale spatial variability of Cs-137 contamination in forest floor and surface soil layers in relation to regional and local characteristics. The mountainous regions of Bulgaria were strongly and inhomogeneously contaminated with cesium-137 due to the Chernobyl accident in 1986. The study confirmed that the cesium in forest soils from two mountainous regions of Bulgaria, SW Rila Mountain and Central Balkan, is located in the forest floor and upper 0-5 cm of soil. In a few cases from Central Balkan the maximum activities are found at a soil depth 5-10 cm. The measured values of cesium activity concentration in Aoh in Rila Mountain region are between 287.9 and 827.1 Bq kg − 1. Greater variations in cesium activity concentration in forest floor are determined for the plots from Central Balkan, where the measured values in Aof are between 85.7 and 2543 Bq kg − 1. The contamination density of Cs-137 in fine soil (b 1 mm) from Rila varies from 0.6 to 6.0 kBq m − 2 while in the Central Balkan plots it is between 1.2 and 19.6 kBq m − 2. The forest floor remains the main reservoir for cesium even years after pollution. The profile distribution of Cs-137 in soil systems shows a tendency of decrease toward deeper layers. The mountainous ecosystems with different types of vegetation were compared on the basis of estimated factor of accumulation (FA). The FA for conifers in Rila Mountain is from 0.28 to 0.69 and in the Central Balkans the FA is from 0.20 to 0.61. The data showed that the spatial distribution of Cs-137 in soil system depends on type of vegetation, humus type and altitude. Due to their low clay content and the high content of organic matter, the mountain forest soils can be considered an excellent ecosystem in which to study the mobility and behaviour of Cs-137 and its transfer into the soil-plant system. Due to the high levels of radiocesium contamination within the mountainous regions of the Central Balkan and the characteristics of soils, the highland mountain herbaceous ecosystems located in this region, in the authors' opinion, could be considered as risk zones to easier soil-to-plant transfer of cesium.

Surface soil and above-ground parts of Pinus kesiya (Three-needled pine) were collected at Wat Chan pine forest to study cycling of 137Cs. Cs-137 derived from nuclear weapons tests up to 1963 was found to have accumulated at a shallow depth (&lt;5 cm) in the forest soil. Calculated total deposition of 137Cs was in the range of previous studies and could be used as a reference for nuclear test deposition of 137Cs fallout in northern Thailand and nearby locations. Potassium in soil does not appear to be a good indicator for long-term radiocaesium cycling. Finally, ‘available’ stable caesium (133Cs) in the soil was found to be an appropriate indicator for studying uptake of 137Cs by Pinus kesiya at Wat Chan.

Using a high-resolution gamma-spectrometer system, the activity concentrations of 7 Be, 137 Cs, 40 K and 226 Ra were determined in the pine needles. Activity concentrations of the concerned radionuclides in the needle samples were as follows:

Stabilization of the 137 Cs profile after 1986, has been observed in a mineral soil in southern Finland. An inversion calculation is presented to determine the 137 Cs profile from the photo-peak (662 keV) counting rate profile. Snow water equivalent (snow mass) can be accurately determined by using snow attenuation of the cesium radiation. When counting, at the same time, the 1461 keV photons of 40 K as well, it may then be possible to determine the surface soil moisture. The 137 Cs profile information is also important for the determination of its contribution to human dose.

The extent and factors influencing sorption of plutonium (Pu) in shale media have been studied in batchtype experiments. The equilibrium time and isotherm of Pu sorption have been firstly determined. The effect of shale grain size, aqueous pH, water/solid ratio, co-existing ions (cations and anions) and temperature were studied as the factors likely to influence Pu sorption. The experimental variables included the following: grain sizes in five ranges, 0.12 to 0.15 mm, 0.15 to 0.18 mm, 0.18 to 0.25 mm, 0.25 to 0.38 mm, and 0.38 to 0.83 mm; solution pH values of 4

In order to understand the sorption behavior of 137Cs and 90Sr into soil sample from Rembang and Subang, it is important to estimate the effect of contact time, ionic strength and concentration of metal ion in the solution. For this reason, the interaction of 137Cs and 90Sr with soil sample has been examined. The study performed at trace concentration (~10-8 M) of CsCl and SrCl2, and batch method was used. NaCl has been selected as a representative of the ionic strength with 0.1; 0.5 and 1.0 M concentrations. Concentration of 10-8~10-4 M CsCl and SrCl2 were used for study the effect of Cs and Sr concentrations in solution. Apparent distribution coefficient was used to predict the sorption behavior. The sorption equilibrium of 137Cs and 90Sr into soil was attained after 5 days contacted with Kd value around 3300-4200 mL/g, where Kd was defined as the ratio of number of radionuclide activity absorbed in solid phase per-unit mass to the number of radionuclide activity remains is soluti...

The accumulation rate of sediments in the Sabine-Neches estuary, near Beaumont, Texas, was studied in four sediment cores using radioisotopes ""Pb and "4~24" Pu. Due to very low and variable activities of unsupported *"Pb in the sediments, the sedimentation rates could not be reliably established using the "'Pb dating method. However, z39,240Pu profiles showed distinct peaks, corresponding to the maximum fallout in 1963, and using these Pu peaks the average sedimentation rates were estimated at 4-S mm yr ' in the upper and lower estuary. Various assumptions that are commonly used in the *"Pb dating method were tested. It was found that the 22hRa activities were in equilibrium with *"U, and the possible loss of 222 Rn was judged to be insignificant. The lack of an exponential profile of excess *"'Pb with depth did not appear to be a direct result of sediment mixing, as the post-depositional mixing rates estimated using a numerical mixing model were low compared to other coastal areas. A significant positive correlation between the amount of < 63.pm fraction sediments and the total *l"Pb activity was observed in the surface sediments. While the hydraulic residence time was relatively short in this estuary (-10 days), the average total residence time of *"Pb was-10 days. Between 50% and 94% of the total ""Pb in the water column was found in the <OS-pm fraction, resulting in low &-values. The measured inventories of excess ""Pb and 2'9,240 Pu in estuarine sediments were only-IO-34% and-19-50%, respectively, of the total expected inventories. It appears that the estuarine retention and sediment inventory of these radionuclides, and by analogy, other particle reactive metals, are a function of the hydraulic residence time, grain size, and possibly complexation of these nuclides with DOC.

We investigated carbon isotopic ratios (δ13C) v. carbon to nitrogen (C : N) ratios for surface sediments throughout a large estuarine system (Río de la Plata, RdlP), combined with sediment cores from adjacent marshes to infer main carbon sources. We also evaluated the influence of the El Niño–Southern Oscillation (ENSO) and associated high freshwater-discharge events on the organic-matter transport within the estuary. The isotopic pattern in surface sediments of the RdlP showed the upper reaches to be influenced by riverine particulate matter (δ13C range: –24 to –26‰). Similarly, in the sediment cores from marshes of the upper reaches, δ13C values decreased from –24‰ in ancient sediments to –28‰ in recent sediments, reflecting an increased contribution of organic matter from land, including C3 plants and freshwater phytoplankton, during the past 50 years. However, the lower reaches represent a depositional environment of marine algae (δ13C range: –21 to –23‰), with no influence of d...

This is a preliminary study of the depth distribution of (137)Cs radionuclides in cultivated anthrosol soil of a 15-year old peach tree plantation at the experimental field &quot;Radmilovac&quot; near Belgrade. Before planting, the soil was ploughed at the depth of 1 m. The soil had not been annually ploughed, irrigated and treated with mineral fertilizers for three years before sampling. Activity concentration for (137)Cs ranged from 1.8 Bq kg(-1) to 35 Bq kg(-1). Along the soil depth it varied highly, reaching as high a total variation coefficient as 83 %. Radiocaesium distribution patterns depended on the extent of soil mixing in the plough layer, as it was mechanically transferred from the surface to the lower soil layers during cultivation. (137)Cs was associated with humus content and fixation to clay fractions in the soil. Our results single out soil&#39;s hygroscopic water as a valuable parameter for (137)Cs behaviour that could be used commonly if the measurement is standar...

face runoff. Augmented lakes receive a portion of their input waters as groundwater from the Floridan Aquifer, which consists of Eocene to Miocene limestones (Scorr 1997). Our study of augmented Lake Charles was designed to: (l) identify the sediment fraction that binds dissolved 226 Ra in groundwater after it enters the lake and (2) to evaluate the stratigraphic distribution of 226 Ra and other constituents in the sediment profile.

We investigated the changes in 137 Cs exchangeable fraction in the soils of contaminated forest ecosystems until 6 years after the Fukushima radioactive atmospheric deposits. For this investigation, we performed chemical extractions of 137 Cs from both organic and mineral soil layer sampled from two forest stands, Japanese cedar (Cryptomeria japonica) and broadleaf deciduous, mainly konara oak (Quercus serrata), which are located 26-27 km inland from the Fukushima Dai-ichi Nuclear Power Plant. The exchangeable 137 Cs as a proportion of the total 137 Cs inventory was only 10% in the organic layer and 6.1% in the mineral soil layer about 5 months after the accident at the Japanese cedar site. We observed an exponential decrease in the proportion of exchangeable 137 Cs in both organic and mineral soil layer samples over the 6-years observation period at both sites. The proportion significantly decreased within 2-4 years after the accident, becoming almost constant (2-4%). These results support the interpretation that contaminated forests have entered a steady-state phase of 137 Cs cycling, although we need more integration for an improved vision of the future of Fukushima forests.

Radionuclides dating have been applied in the chronological series of sediment core recovered from Satopanth Tal to estimate the sedimentation rate and its age. Several models include CRS and slope method, and 137 Cs peak methods have been adopted. The depth concentration of 210 Pb exc in the core determines the various parameters like sedimentation rate, geochronology, inventory, and mass fluxes. The CRS model and slope method infer the sediments deposited at a rate of 0.79 ± 0.04 cm/year dated to 120 years. Distinct peaks on 1963 and 1986AD, the 137 Cs record estimate the mean sedimentation rate is 0.745 ± 0.03 cm/year respectively and dated to 77 years.

The construction of Akkuyu Nuclear Power Plant (NPP) was launched in 2018 and the plant is expected to be operative by the year 2023. Being situated in the Mediterranean coastline, Akkuyu NPP will be the first nuclear power generation facility in Turkey. The plant will have four Russian VVER-1200 type pressurized water reactors with a total installed capacity of 4800 MW. In this study, atmospheric dispersion and ground level deposition of Cs-137 and I-131 released from a possible accident in Akkuyu NPP was estimated using a Lagrangian particle dispersion model, FLEXPART, for different time periods representing relatively extreme meteorological conditions for Mersin. The source term used in simulations was assumed the same with that of the Chernobyl NPP accident that occurred in 1986. In addition, cumulative dose and risk values were calculated from FLEXPART output datasets considering potential exposure pathways such as inhalation, ground-shine exposure and cloudshine exposure. The results were further analyzed with python codes and dose and risk maps were created for local and regional scales. According to results of the study, it was found that the vicinity of Mersin and Central Anatolia were simulated to be the most significantly affected areas from the accident under both scenario conditions. The northern and western parts and all coastlines of Turkey were simulated to be more contaminated in the simulations conducted under December 2009 conditions, whereas southern and western parts of Turkey and some parts of Middle East countries like Syria, Iraq and Lebanon were simulated to be comparatively more contaminated under August 2010 conditions. The results indicated that radioactivity levels exceeding 100 kBq/ m 2 were observed near the accident site under both scenario conditions. Values exceeding 10 kBq/m 2 level were simulated in western Turkey in the first scenario whereas similar values were found in eastern Turkey in the second scenario. Furthermore, the results indicated 7-day thyroid dose values ranging between 0.10 mSv and 10.0 mSv in western and eastern parts of Mediterranean region for the first and the second scenario, respectively. Similarly, 1-year effective dose of only Cs-137 ranged between 0.1 mSv and 1.0 mSv around Akkuyu NPP site in both scenarios. The results revealed that meteorological conditions were among the most important parameter for the fate and transport of radioactivity originating from such a catastrophic event.

In this study an attempt was made to investigate the physical, chemical and pedogenetical soil properties of black pine forests at over 1400 metre (m) altitude of Kazdagi mountainous uplands. Soil profiles (37 numbers) were dug, examined and sampled considering the horizons and soil volume weight, fine soil weight, stoniness, pH, total nitrogen, soil organic carbon and pedogenesis alterations were tried to be explored in relation with elevating altitude. While the altitude increased, soil organic carbon and total nitrogen values decreased at A horizon, and pH decreased at Bw horizons. Soil volume weight, fine soil weight, stoniness values of A horizon has positively and strong correlation with elevation with the coefficient values 0.699, 0.518 and 0.573 respectively at 0.01 significance. The highest regression values between altitude and volume weight, soil organic carbon contents (%) and soil total nitrogen contents (%) were detected with R2 coefficients 0.489, 0.295 and 0.247 for ...

In this study, 210 Pb(210 Po) activity concentrations in surface soils taken from cultivated lands in the Buyuk Menderes Basin in Aegean Region, Turkey were determined. The 210 Pb(210 Po) activity in soil varies from 0.013 to 0.135 Bq/g with a mean value of 0.041 Bq/g. Its distribution fitted close to normal curve. The mean annual effective dose equivalent was found to be 0.91 Sv/y. The data obtained were statistically evaluated to explain the 210 Pb(210 Po) distribution in the cultivated lands. The effect of organic matter, clay, silt, sand contents and pH of the soil on the relative adsorption of the 210 Pb(210 Po) on the surface soils was also studied.

Post-depositional mobility of 137Cs, 239+24°pu and 21°pb was assessed in six small lake basins by comparing sedimentary nuclide profiles with their known fallout history. Laminae couplets, when present, were determined to be varves because the 137Cs and 239-t-240pu 1963 fallout peaks are present in laminae couplets corresponding to years 1962-1964. There is no evidence of mobility of 21°Pb, because 1) mass accumulation rates based on 21°pb agree with those based on 137Cs and 239 + 240pu peak depths and with those based on varve counts, and 2) 21°Pb ages agree with varve ages. Significant mobility of 137Cs is evident from the penetration of 137Cs to depths 15-20 cm deeper than 239 + 2 4 0 p u ' Deep penetration of 137Cs in spite of a sharp gradient below the peak is interpreted by a numerical model to suggest that ~37Cs is present in two distinct forms in these sediments, 67-82% as an immobile form and 18-33% reversibly adsorbed with a Kd of approximately 5000. The profiles can be interpreted equally well assuming a small portion of the total 137Cs was present as an extremely mobile phase (K~<<5000) in the months to years following peak fallout, slowly becoming more strongly adsorbed. High NH + concentrations in porewaters may enhance diffusion of the mobile form of 137Cs, but not of the immobile form of I37Cs that defines the sharp gradient. Mobility of 137Cs is likely also enhanced by the low clay content and the high porosity of these sediments. Thus the first detection of 137Cs in the sediments cannot automatically be assumed to correspond to a date of 1952 (initial testing of thermonuclear weapons), although the depth of the peak can be assumed to correspond to 1963 (the year of maximum fallout from testing of thermonuclear weapons). 239 + 240pu is a more reliable sediment chronometer than I37Cs because it is significantly less mobile.

Bio-diffusion mixing rates (D b) were estimated from depth profiles of excess 210 Pb and 137 Cs in three sediment cores collected from Mumbai Harbour Bay (MHB) using a steady state vertical advection-diffusion model. The mean of 210 Pb and 137 Cs derived D b values along the studied area were obtained to be about 23 and 36 cm 2 y −1 respectively. These derived values were within the range of literature values reported for other equivalent environment internationally. The relatively higher D b values for 137 Cs profiles demonstrated that particles have diffused more intensely within the surface layer of sediments over 1 year. Conversely, low D b values for 210 Pb indicate slow mixing rates in the sediment profile which might be resulted from low 210 Pb flux and diffusion of 222 Rn to the seafloor. The significant differences between 210 Pb and 137 Cs derived D b values among cores indicate that there appeared to be as regional differences in sediment properties and local variability in the intensity of seafloor mixing. Furthermore, D b values also depend on differences in characteristic time and depth scales of radionuclides in cores, benthic fauna abundances, organic carbon flux to the sediments and primary production in overlying surface waters. Comparison of 210 Pb derived D b values with those calculated from 137 Cs distributions reveals better agreement for core 2 than core 1 and 3. The agreement may be fortuitous because 137 Cs appears significantly deeper than 210 Pb in all cores. It was also observed that D b values increases as sediment accumulation rate increases for both radionuclide.

levels and variation of 13'Cs in tea plant leaves from 1986-1992 were determined over the coast line of the Eastern Black Sea region in Turkey. The decrease of 137Cs radionuclide concentration in tea plant leaves may be described by a double exponential function with 94.8% activity lost with a T,, of 125 d and 5.2% activity lost with a Tee of 1,114 d.

We investigate the caesium concentrations in soils in mountain areas near Gori nuclear power plant in Korea, focusing on the measurement limits to the 134 Cs. In order to lower the minimum detectable amount (MDA) of activity for the 134 Cs, we have used the ammonium molybdophosphase (AMP) precipitation method to get rid of the 40 K existing in natural radioactivity, which reduces the MDA of activity about ten times smaller than those without the AMP precipitation method. The MDA results for the 134 Cs were found to be in the range between 0.015 and 0.044 Bq/kg-dry weight. In order to diminish the background, we also have measured a part of the soil samples in Yangyang, a small town in the east coast of Korea. However, it turns out that in order to detect the 134 Cs in the samples the MDA should be reduced to the level of mBq/kg-dry weight.

This paper introduces some modelling approaches for predicting the influence of hazardous accidents at nuclear reactors on groundwater quality. Possible pathways for radioactive releases from nuclear power plants were considered to conceptualize boundary conditions for solving the subsurface radionuclides transport problems. Some approaches to incorporate physical-and-chemical interactions into transport simulators have been developed. The hydrogeological forecasts were based on numerical and semianalytical scale-dependent models. They have been applied to assess the possible impact of the nuclear power plants designed in Russia on groundwater reservoirs.

Radionuclides dating have been applied in the chronological series of sediment core recovered from Satopanth Tal to estimate the sedimentation rate and its age. Several models include CRS and slope method, and 137 Cs peak methods have been adopted. The depth concentration of 210 Pb exc in the core determines the various parameters like sedimentation rate, geochronology, inventory, and mass fluxes. The CRS model and slope method infer the sediments deposited at a rate of 0.79 ± 0.04 cm/year dated to 120 years. Distinct peaks on 1963 and 1986AD, the 137 Cs record estimate the mean sedimentation rate is 0.745 ± 0.03 cm/year respectively and dated to 77 years.

The results of the gamma-spectrometric measurements in a 16500 ha large region of south-western Serbia, are presented. Activity concentrations of 40K, 137Cs, and 210Pb in different deciduous and evergreen trees in the region are investigated. For all the investigated isotopes, there is a tendency that, on average, the lowest activity concentrations were found in tree stems, then in leaves, while the highest ones were in the soil. Statistical analysis did not show any differences between activity concentrations of leaves and needles, showing that both leaves and needles could be equally well used as a biomonitors.

The Fukushima Daiichi nuclear power plant disaster caused serious radiocesium ( 137 Cs) contamination of forest ecosystems over a wide area. Forest-floor organic layers play a key role in controlling the overall bioavailability of 137 Cs in forest ecosystems; however, there is still an insufficient understanding of how forest types influence the retention capability of 137 Cs in organic layers in Japanese forest ecosystems. Here we conducted plot-scale investigations on the retention of 137 Cs in organic layers at two contrasting forest sites in Fukushima. In a deciduous broad-leaved forest, approximately 80% of the deposited 137 Cs migrated to mineral soil located below the organic layers within two years after the accident, with an ecological half-life of approximately one year. Conversely, in an evergreen coniferous forest, more than half of the deposited 137 Cs remained in the organic layers, with an ecological halflife of 2.1 years. The observed retention behavior can be well explained by the tree phenology and accumulation of 137 Cs associated with litter materials with different degrees of degradation in the organic layers. Spatial and temporal patterns of gamma-ray dose rates depended on the retention capability. Our results demonstrate that enhanced radiation risks last longer in evergreen coniferous forests than in deciduous broad-leaved forests.

This study is established to evaluate the impact of iron and steel industry in Egypt on the public and environment.The study involved five companies for iron and steel production. Forty-two raw materials samples, eight waste sampleswere collected from the selected companies as well as sixty-eight soil samples were collected inside and around the companies. The activity concentrations of 226 Ra, 232 Th, 40 K and 137 Cs were determined applying Hyper-Pure Germanium (HPGe) detector. Radiological health parameters such as radium equivalent,annual gonadal equivalent dose and excess lifetime cancer risk were estimated to assess health implication of exposure to the general public and workers to the studied samples. Heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, and As) were determined by ICP-OES. Contamination factor, contamination degree and pollution load index of heavy metals were estimated; in addition pollution load index (PLI) of zones was used to compare the pollution levels between the studied companies. The activity concentration of 226 Ra, 232 Th, 40 K, and 137 Cs in soil samples ranged from < 0.7 to 257.5, < 0.6 to 25.4, 3.63 to 1578, and < 0.04 to 18.6 Bqkg-1 respectively. Soil samples have hazard indices within safe limit and don't pose a significant health hazard except some soil samples around the first company. Concentration of Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, and As ranged from (0.038 to 57), (2.265 to 922.65), (3.97 to 774.2), olyptical Characteristics Of Cake Fortified By Irradiated Broccoli (Brassica Oleracea L.Var Italica) Powder (15) ABSTRACT l and Organolyptical Characteristics Of Cake Fortified By oli (Brassica Oleracea L.Var Italica) Powder aadani, R.

A b s t r a c t: Concentration of natural radionuclides in soil and plants are crucial parameters for defining the level of contamination of the environment. The samples for analysis were collected from the 14 localities of the surrounding of Skopje, of cultivated and uncultivated soil. The specific activity of radionuclides 232 Th, 226 Ra and 40 K are determined by gamma spectrometry. The analysis results show that the mean value of 232 Th specific activity in cultivated soil was 43.74 ± 4.99 Bq•kg -1 , while in uncultivated soil it was 35.70 ± 5.65 Bq•kg -1 . The 226 Ra specific activity had a mean value of 34.09 ± 6.53 Bq•kg -1 and 28.30 ± 5.54 Bq•kg -1 in cultivated and uncultivated soil, respectively. The specific activity of 40 К from all localities was higher than the one of 232 Th and 226 Ra, and in cultivated soil the mean value was 608.12 ± 70.43 Bq•kg -1 , while in uncultivated soil it was 506.54 ± 59.96 Bq•kg -1 . From the same locations corn samples were also collected for analysis. Concentration of natural radionuclides in corn is lower then referent values. From the results ttransfer factor (TF) of natural radionuclides from soil to corn was calculated.

The evolutionary environmental history of Bera Lake was studied using the fallout radioisotopes 137 Cs and 210 Pb. Cs horizons in the all ten studied cores showed a constant rate of 210 Pb supply along all distinctive layers in each core. The lithology of layers significantly affected the variation of 210 Pb value with depth. The chronology of Bera Lake sediment was conducted using the Constant Rate of Supply (CRS) model. The 1963 fallout maximum 137 Cs from atmospheric testing of nuclear weapons found in all selected master cores at the depth of 40 cm. The mean pre-1950 sediment accumulation rate was ranged between 0.06 ± 0.02 and 0.16 ± 0.2 g cm -2 y -1 . Environmental impacts of five deforestation projects performed from 1972 to 1995 at the catchment area, contributed significantly toward increasing the sedimentation rate within Bera Lake. Besides the 137 Cs horizons, the charcoal horizon at the lower contact of white sandy mud revealed the datum of maximum deforestation in the study area. 210 Pb dates using the CRS model correlated historical sediment fluxes to anthropogenic changes in Bera Lake catchment area. Organicrich sediments deposited mostly at the top of the Bera Lake sediment columns with a mean rate of 0.2 ± 0.1 g cm -2 y -1 since 1994. High biomass productivity of mature oil palm plantations, which were developed in the catchment area, dictated organic-rich deposit distribution. This study highlighted capability of radioisotopes to reconstruct long-term (100-150 years) history of a natural lake at a tropical area where surrounding catchment has extensively deforested over the recent decades.

Despite previous studies on the restoration of tactile sensation to the fingers and the hand, there are no examples of use of the routed sensory information to finely control a prosthestic hand in complex grasp and manipulation tasks. Here, it is shown that force and slippage sensations can be elicited in an amputee by means of biologically inspired slippage detection and encoding algorithms, supported by a stick-slip model of the performed grasp. A combination of cuff and intraneural electrodes was implanted for 11 weeks in a young woman with hand amputation and was shown to provide close-to-natural force and slippage sensations, paramount for substantially improving manipulative skills with the prosthesis. Evidence is provided about the improvement of the participant’s grasping and manipulation capabilities over time resulting from neural feedback. The elicited tactile sensations enabled the successful fulfillment of fine grasp and manipulation tasks with increasing complexity. Gr...

Sugai, S.F., Alperin, M.J. and Reeburgh, W.S., 1994. Episodic deposition and 137Cs immobility in Skan Bay sediments: A ten-year 2X°pb and 13~Cs time series. In: M.I. Scranton (Editor), Variability in Anoxic Systems. Mar. Geol., 116: 351-372. A geochronology time series provides a powerful tool for elucidating sedimentary processes such as episodic deposition and diffusive mobility of particle-reactive constituents. Depth distributions of 21°Pb and 137Cs from Skan Bay, Alaska were determined for sediment cores collected in 1980, 1984, 1987, and 1990. Sediment X-radiographs reveal distinct layers indicating that sediments were not continuously mixed by bioturbation. However, the geochronology time series is inconsistent with an undisturbed, steady-state sediment column. Profiles from 1980, 1984, and 1990 reveal subsurface regions in which 21°pb activity is relatively constant. In addition, the depth of the primary 137Cs maximum (reflecting the 1963 peak in atmospheric bomb testing) do...

In the present study, we reported the investigation of radiocesium migration from steep slope surrounding catchment to water body based on the radiocesium distribution and soil to sediment ratio. It was confirmed that the radiocesium was derived from the Fukushima accident by considering the 134 Cs to 137 Cs ratio corrected to the released day which is about 1. We found the higher radiocesium inventory in higher elevation area and steep slope forest catchment, revealing the atmospheric dry initial deposition-derived radiocesium and high retention of the forest zone. The radiocesium distribution data revealed that the radiocesium migrated more from the transition zone to the water body than from forest catchment, and accumulated in the deeper layer of sediment. The lower value of 137 Cs soil to sediment ratio provided an evidence of radiocesium migration from the catchment and its accumulation in the sediment. The physicochemical property of surface soil was revealed as one of the possible factors of radiocesium high retention in forest catchment.

The Old Woman Creek estuary (OWC), a coastal wetland in Ohio, traps 47% of incoming suspended sediment and has a sedimentation rate of ~1 cm/yr. Persistence of the OWC wetland and other coastal wetlands with high sedimentation rates seems problematic unless some previously trapped sediment is exported from the wetland. Suspended sediment, 7 Be, and 210 Pb xs budgets for a single runoff event in the OWC wetland were developed to understand short-term sediment dynamics. The budgets were balanced by subtracting the sum of the imports from the sum of the exports and attributing the difference to either deposition on, or resuspension from, the wetland bed. The wetland exported 118 ± 2%, 93 ± 1%, 74 ± 2% of the delivered sediment, 210 Pb xs , and 7 Be, respectively, during the studied event. The 7 Be/ 210 Pb xs ratios of the total suspended solids and bed sediment were distinct from one anther and used to quantify the relative proportions of recently delivered and resuspended bed material in the sediment efflux from the wetland. The 7 Be/ 210 Pb xs ratios suggest that 26 ± 20% of the sediment efflux was resuspended from the bed. While the wetland trapped 13 ± 3% of the sediment it received during the runoff event, resuspension and removal of previously deposited sediment in the wetland was sufficiently large to result in a net loss of sediment from the wetland during the event. Thus, the Old Woman Creek wetland is a sediment sink over the long-term, but can be a net exporter of sediment during single events.