Transfer Factor Of 137Cs Research Articles

A study on the transfer of radionuclides and of the resulting radiation dose assessment for marine organisms on the eastern coast of Yantai city

Oceans are repositories of radionuclides. Radionuclides are transferred through the food chain and cause ionizing radiation hazards for marine organisms. In this study, the transfer characteristics of 226Ra, 40K, 14C, 3H, 137Cs and 90Sr in organisms at different trophic levels in the eastern coast of Yantai city were investigated. The risk of ionizing radiation to organisms was assessed using the ERICA Tool 2.0. The results show no significant changes in the concentration of any of the nuclides in the coastal area compared to the preoperation period of the nuclear power plant. The transfer factor of 137Cs, 40K, 226Ra, 14C, 90Sr and 3H at the different trophic levels of marine organisms were 2.09, 1.29, 1.17, 1.15, 1.06 and 0.74, respectively. The dose rates of ionizing radiation to organisms from six radionuclides ranged from 32.02 nGy·h-1 to 195.49 nGy·h-1 and had a mean value of 102.86 ± 57.30 nGy·h-1. The main artificial radionuclides (14C, 3H, 90Sr, 137Cs) released by nuclear power plants in the study area produced negligible radiation doses to marine organisms. However, other artificial radionuclides present in the effluents of nuclear power plants (99Tc, 110mAg and 131I) as well as other natural radionuclides (includes 210Po, 210Pb, etc) were not included, and further evaluation of these is recommended.

Quality and safety of products using GM soybeans in the diet of bulls

The production of high-quality and safe food products in areas contaminated by radiation due to the Chornobyl Nuclear Power Plant accident remains a pressing issue. The aim of this study was to determine the concentration and transfer factors of 137Cs, Pb, Cd, Cu, and Zn in bull products when including various high-protein feeds, such as narrow-leaved lupin and genetically modified soybean, in their diets. The study employed zootechnical methods (design and conduct of a scientific-economic experiment on animals), radiological and spectrometric methods (determination of the concentration of 137Cs, Pb, Cd, Cu, and Zn in feeds, longissimus dorsi muscle, liver, kidneys, and testes of bulls), and statistical methods. It was established that when using GM soybean in the grain mixture, the concentration of 137Cs in the muscle tissue of animals in Group II (experimental) decreased relative to the control by 2.57 Bq/kg, or by 40.5% with a statistically significant difference between groups (P > 0.99). Furthermore, the transfer factor of the radionuclide into the muscle tissue of animals in Group II compared to Group I also had 2.15% abs. lower. The content of Pb in the muscle tissue of bulls in both experimental groups exceeded the maximum permissible concentration by 2.52-2.78 times, while the concentration of Cd in the longissimus dorsi muscle and Cu in the liver of animals in Group II also exceeded sanitary-hygienic requirements by 10.0% and 2.0%, respectively. The introduction of 40% (by mass) of maize grain and 30% of GM soybean into the grain mixture instead of the same amount of wheat and lupin chop during the fattening of animals in the third zone of radioactive contamination contributed to significantly higher content and transfer of heavy metals into muscle tissue: Pb – by 10.3% and 0.10% abs., Cd – 10.0 and 0.03, Cu – 17.2 and 0.53, and Zn – by 17.2% and 2.40% abs. The results of the research can be used in agricultural enterprises and private households that produce livestock products in areas with a high anthropogenic load

The Impact of Inoculation of Two Strains of Rhizobacteria on Radionuclide Transfer in Sesbania Grandiflora.

Transfer factors of some naturally-occurring and artificial radionuclides from an agricultural soil to rhizobacteria-treated Sesbania grandiflora, a small leguminous tree, were studied. Two plant growth promoting rhizobacteria (PGPR) strains (SCR17 and PCE2) were used to carry out an agricultural experiment in pots in semi-arid region (Syria). The results showed the bacterial strain (SCR17) increased the transfer and accumulation of 238U and 40K in Sesbania grandiflora, while both bacterial strains showed no effect on the accumulation of 234Th, 226Ra, 210Po and 210Pb in the treated plants. The transfer factor of 137Cs from soil to rhizobacteria-treated Sesbania grandiflora was negligible. The values of the transfer factors of 234Th, 226Ra, 210Po and 40K were found to be within the global values, while the values of the transfer factors of 238U and 210Pb were found to be relatively higher. This study highlights the importance of using Phytoremediation by PGPR strains for radionuclides-contaminated soils. Therefore, this method is a promising technique for the restoration and rehabilitation of contaminated sites with radionuclides, as it is low cost, easy to apply, and environmentally friendly.

Effects of cattle manure compost application on crop growth and soil-to-crop transfer of cesium in a physically radionuclide-decontaminated field

Resuming crop production in physically decontaminated fields affected by radiocesium (134Cs and 137Cs) releases is crucial for restoring impacted areas. However, surface soil excavation to reduce radiocesium may lead to lower crop yield due to the loss of fertile topsoil. This study aimed to assess the effects of cattle manure compost (CMC) application on soil properties, crop growth, and 137Cs soil-to-crop transfer in a physically decontaminated field and pot experiment. Field trials were conducted during 2018–2022, with CMC (1 and 2 kg m−2 year−1) applied alongside conventional fertilization (CMC1 and CMC2 plots, respectively) in 2018–2019 and conventional fertilization alone in 2020–2022. Additionally, a pot experiment was used to evaluate the impact of CMC application in soil (1 kg m−2 year−1 for 5 years) on 137Cs transfer. In the field trial during 2018–2019, CMC1 and CMC2 plots exhibited higher soybean shoot dry weight (DW) compared with plots receiving conventional fertilization and additional K fertilizer (+K2O). CMC application also improved soil nutrient content. The transfer factor of 137Cs (TF-137Cs: plant 137Cs activity concentration/soil 137Cs activity concentration) followed the order CMC2 < CMC1 ≈ +K2O < conventional fertilization only (CF) and was negatively correlated with soil exchangeable K (Ex-K). During 2020–2022, when all plots received conventional fertilization alone, grain yields were higher in CMC1 and CMC2 plots than in the +K2O plot, with the lowest TF-137Cs in CMC2 plot followed by CMC1, +K2O, and CF plots. The pot experiment confirmed that CMC soil had a lower TF-137Cs and higher plant DW compared with CF soil with the same Ex-K level. Additionally, the soil exchangeable 137Cs (Ex-137Cs) level was significantly lower in CMC soil than CF soil. These findings demonstrate the potential of CMC application to improve crop growth and reduce 137Cs transfer in physically decontaminated fields.

Transfer of 137Cs and 90Sr from soil-to-potato: Interpretation of the association from global fallout in Aomori to accidental release in Fukushima and Chornobyl

Ceasium-137 and 90Sr are major artificial radionuclides that have been released into the environment. Soil-to-plant transfer of radionuclides is an important route to food contamination. The radionuclide activity concentrations in crops must be quantitatively predicted for estimating the internal radiation doses from food ingestion. In this study, soil and potato samples were collected from three study sites contaminated with different sources of 137Cs and 90Sr: Aomori Prefecture (global fallout) and two accidental release areas (Fukushima Prefecture and the Chornobyl exclusion zone). The 137Cs activity concentrations in the soil and potato samples widely ranged from 1.0 to 250,000 and from 0.048 to 200,000 Bq kg−1 dry weight, respectively. The soil-to-potato transfer factor of 137Cs also ranged widely (0.0015–1.1) and decreased with increasing concentration of exchangeable K. Meanwhile, the activity concentrations of 90Sr in the soil and potato samples were 0.50–64,000 and 0.027–18,000 Bq kg−1 dry weight respectively, and the soil-to-potato transfer factor of 90Sr was 0.023–0.74, decreasing with increasing concentration of exchangeable Ca. The specific activity ratios of 137Cs/Cs and 90Sr/Sr in the exchangeable fraction were similar to those in potatoes, with a factor of 3 in the ±95 % confidence intervals over six orders of magnitude and a factor of 2 in the ±95 % confidence intervals over five orders of magnitude, respectively. According to the data, the accuracy of predicting the activity concentrations of 137Cs and 90Sr in potatoes can be improved by applying the specific activity ratios of 137Cs/Cs and 90Sr/Sr in the exchangeable fraction. This approach accounts for variable factors such as the effects of K and Ca fertilization and soil characteristics. It also emphasizes the benefit of determining the stable Cs and Sr concentrations in potatoes and other crops prior to possible future contamination.

Radioactivity research in mosses from typical Karst Regions in Leye Tiankeng, Southern China

Radionuclides in environmental ecosystems have ecotoxicity and health impact on human and environment, so radioactive contamination has always been one of the global concerns. This study mainly focused on the radioactivity of mosses collected from the Leye Tiankeng Group in Guangxi. The activities of 239+240Pu measured by SF-ICP-MS and 137Cs measured by HPGe in moss and soil samples are as follows: 0–2.29 Bq/kg in mosses and 1.5–11.9 Bq/kg in soils for 137Cs, and 0.025–0.25Bq/kg in mosses and 0.07–0.51Bq/kg in soils for 239+240Pu. The range of 240Pu/239Pu atom ratios (0.201 in mosses and 0.184 in soils) and 239+240Pu/137Cs activity ratios (0.128 in mosses and 0.044 in soils) indicated that the 137Cs and 239+240Pu in study area were mainly contributed by global fallout. 137Cs and 239+240Pu showed similar distribution in soils. However, their behaviors in mosses were quite different due to the differences in the growth environment of mosses. The transfer factors of 137Cs and 239+240Pu from soil to moss varied in different growth stages and specific environments. A weak positive correlation among 137Cs, 239+240Pu in mosses and soil-derived radionuclides suggested that resettlement was predominant here. The negative correlation between 7Be, 210Pb and soil-derived radionuclides indicated that 7Be and 210Pb came from atmospheric components, while the weak correlation between them suggested that their specific sources were different. The Cu and Ni were moderately enriched in mosses here due to the use of agricultural fertilizers, At the same time, Zn was at a high level in the Lilang area, where transportation was more developed.

Биологическая доступность 137Cs и 90Sr в дерново-подзолистых почвах в отдаленный период аварии на Чернобыльской АЭС

The content of 137Cs and 90Sr forms in soddy-podzolic automorphic and gleyic soils of different textures (loamy, sandy loamy, sandy) was studied. It has been established that over a long post-accident period, the physical and chemical forms of 137Cs and 90Sr have been transformed in soils, and a dynamic balance has come in their content. 137Cs compounds have undergone non-exchange fixation, and their content in the form available to plants is currently an insignificant fraction -5-15 %. 90Sr compounds, on the contrary, are predominantly in easily accessible forms, which make up from 60 to 75 % in soddy-podzolic soils, 67 % on average. The transfer factor of 137Cs, depending on the granulometric composition of soils, decreased on average in grain crops by 3.0-6.7 times, in potato tubers - by 5.0-7.5 times. The parameters of 90Sr intake into plants decreased most intensively in the first 1-2 years after the accidental fallout, which was mainly due to the transformation of its water-soluble compounds into exchangeable forms, and over the past 30-36 years they have not practically decreased. Due to the high mobility of 90Sr in the soil, the transfer factor into agricultural crops are significantly higher compared to 137Cs - into grain crops by more than an order of magnitude, into potatoes - by an average of 5 times. Currently, the bioavailability parameters of 137Cs and 90Sr have stabilized and no significant changes are observed. Therefore, based on the current situation and the transfer coefficients of these radionuclides from soil to plants, it can be concluded that the main problems associated with obtaining standard clean crop products can occur on soils contaminated with 90Sr.

Aggregated transfer factor of 137Cs in edible wild plants and its time dependence after the Fukushima Dai-ichi nuclear accident

We obtained the aggregated transfer factor (Tag) for 10 common edible wild plant species (four perennial spermatophytes, bamboo shoot, two tree species, and three perennial pteridophytes) in northeastern Japan. Measurement of Tag was carried out in 2012–2019 and we also used publicly available data for 2012–2019: food monitoring data and total deposition data from an airborne survey. The Tag obtained from actual measurements agreed well with Tag values calculated from the publicly available data. The sampling locations were only identified at the municipal level and uncertainty of the deposition for the publicly available data, and thus Tag values showed substantial variation. The Tag of the perennial spermatophytes, including bamboo shoot, and perennial pteridophytes showed single exponential decline with effective half-lives of approximately 2 years, whereas those of tree species did not show distinct temporal change. These results imply that data since 2014 are applicable for Tag estimation for long-term potential ingestion dose in the future to the public because of the slow decline. The calculated Tag values of all species for 2014–2019 ranged from 6.1 × 10−5 to 5.2 × 10−3 m2/kg-fresh mass. The maximum Tag value was observed for the tree koshiabura (Chengiopanax sciadophylloides) and the minimum value was observed for the perennial spermatophyte giant butterbur (Petasites japonica). Tree species showed higher Tag than spermatophyte and pteridophyte perennials.

Transfer factor of 137Cs and 90Sr to various crops in semi-arid environment

This study focuses on evaluating the transfer factor (Fv) of 137Cs and 90Sr from two basic soil types in the country, i.e. Aridisol and Inceptisol, to 18 common crops belong to six groups, i.e. cereals, leafy, non-leafy vegetables, tubers, leguminous fodder and leguminous vegetables. In addition, the variation of Fvs of 137Cs and 90Sr with crop components, growth stages of plants and the influence of mineral fertilisation were investigated. The experiments were performed in an open field and the results were expressed as geometric means.The data revealed that Fvs of both radionuclides were higher in Aridisol than Inceptisol for all crops by about 1.03–4.86 fold. Fvs of 90Sr were more enhanced than those of 137Cs by one or two orders of magnitude despite plant group and soil type, e.g. Fvs ranged 0.12–5.2 for 90Sr and 0.0035–0.26 for 137Cs in the vegetative portion of the crops.Among the six crop groups investigated, cereals gave the lowest Fvs for both radionuclides, which is compatible with the data reported worldwide. The average Fvs observed in cereal grains reached 0.001 for 137Cs and 0.017 for 90Sr, in Inceptisol. However, Jew-mallow (one of the major leafy vegetables in the country that is consumed throughout the year) reflected the highest Fvs for 137Cs and 90Sr, i.e. 0.11 and 2.44 in Inceptisol, respectively. Comparing Fvs of the radionuclides through the growing stages of the plants indicated enhanced values at the mid-season than harvest as a consequence of the decrease of the physiological activity of the plants towards maturation and dilution made by the increase of plant biomass; e.g. Fvs dropped to about 3.0 fold for 137Cs and 2.2 for 90Sr, in Aridisol. Mineral fertilisation of soil (for four crops, i.e. sorghum, barley, spinach and alfalfa) reduced Fvs for both radionuclides to an extent of 30% probably because of the competing action of their stable nutrient analogues NH4+, K+ or Ca2+ or because of growth dilution.The data presented herein would form a baseline when decision of land-investment or phytoremediation is the preferable countermeasure for the management of 137Cs and 90Sr-contaminated soil in semi-arid environment.

Динаміка коефіцієнтів переходу та накопичення 137Cs трав’янистою рослинністю природних луків на торф’яно-болотних ґрунтах у початковий період після імітації радіоактивних випадань

Динаміка коефіцієнтів переходу та накопичення 137Cs трав’янистою рослинністю природних луків на торф’яно-болотних ґрунтах у початковий період після імітації радіоактивних випадань

Temporal dynamics of 137Cs distribution in soil and soil-to-crop transfer factor under different tillage systems after the Fukushima Daiichi Nuclear Power Plant accident in Japan

The accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in Japan in 2011 released a large amount of radionuclides, primarily radiocesium-137 (137Cs; half-life: 30 years), resulting in long-term contamination of soil and consequently crops. Tillage is a common agricultural management practice that alters the vertical distribution of nutrients in the soil. However, the effect of tillage on 137Cs contamination in soil and crops over time remains unclear. In this study, we investigated the temporal changes in the vertical distribution of 137Cs in the soil, concentration of 137Cs in soybean and cover crops, and the transfer factor (TF) of 137Cs from the soil to crops under three tillage systems (rotary cultivation [RC], moldboard plow [MP], and no tillage [NT]; main factors) using three cover crops (hairy vetch, winter rye, and fallow weeds; side factors). The amount of 137Cs in the soil decreased exponentially with soil depth under the NT and RC treatments. By contrast, 137Cs showed uniform distribution at each soil depth tested under the MP treatment since 2012. The exchangeable 137Cs demonstrated a similar tendency as 137Cs. The 137Cs concentration in soybean (including grain and residue) and cover crops decreased exponentially with time. Consistently higher 137Cs concentration was observed in soybean grains under the NT treatment, suggesting that tillage continuously reduced the concentration of 137Cs in soybean over 7 years since the FDNPP accident. The TF of 137Cs from soil to soybean and cover crops decreased continuously over time; however, 137Cs concentration of soybean grain showed a positive linear correlation with its annual variation rate. Additionally, TF showed a positive logarithmic correlation with 137Cs relaxation depth in the soil. These results enhance our understanding of the long-term behavior and radioecology of 137Cs in agroecosystems in Japan since the radionuclide accident.

Effects of potassium fertilization on Radiocaesium transfer from sandy soil to barley (Hordeum vulgare L.)

Uptake and translocation of radiocesium artificially added to sand soil cultivated with barley as affected by different rates of potassium were traced in outdoor pot experiment. Experimental soil was contaminated with 0.01 and 0.1 mM 137Cs equal to (200 and 400 Bq/kg) in the form of CsCl and incubated for 14 days prior to 150 days plant growth period. The transfer factor (TF) average values from soil-to-total biomass were found to range from 0.40 up to 0.53 as affected by interaction between tested treatments. Increasing K rates from 125 to 250 kg/ha markedly reduced the mean averages of TFs of 137Cs from soil-to-roots by about 24 to 68%, respectively and from soil-to-total biomass by about 36 and 74%, respectively lower than corresponding control. In all cases, the discrimination factor was below unity, indicating that Cs is less efficiently absorbed from soil than its nutrient analogue K.

Phytoavailability of 137Cs and stable Cs in soils from different parent materials in Fukushima, Japan

Weathered micaceous minerals (micas) are able to release potassium ion (K+) and fix caesium-137 (137Cs), both of which reduce soil-to-plant transfer of 137Cs. Among micas, trioctahedral micas such as biotite is expected to have a stronger ability to supply nonexchangeable K+ and a higher amount of Cs fixation sites than dioctahedral micas such as illite. Although biotite is predominant in granitic soils (G soils), illite is mainly dominant in sedimentary rock soils (S soils). Therefore, we hypothesized that G soils have a lower 137Cs transfer risk than S soils because of this difference in mineralogy. The objective of the present study was to determine the transfer factor (TF) of 137Cs and stable Cs (SCs) and to elucidate the determinant factors of TFs for G and S soils in Fukushima, Japan. Pot experiments were carried out with rice (Oryza sativa L. cv. Hokuriku 193) in G and S soils to determine the TF of 137Cs (TF-137Cs) and stable Cs (TF-SCs) under K-deficient conditions. TF-137Cs and TF-SCs were highly correlated, and both were significantly lower for G soils than for S soils. Higher TF values were shown for soils with lower amounts of exchangeable and nonexchangeable K or with higher percentages of exchangeable 137Cs (ex137Cs). The percentage of ex137Cs was negatively correlated with the amount of Cs fixation sites, represented by the radiocaesium interception potential. Thus, we concluded that smaller TF values for G soils were caused by a stronger ability to supply nonexchangeable K+ and a higher amount of Cs fixation sites. These findings will contribute to the establishment of soil screening techniques based on 137Cs transfer risk in Fukushima prefecture.

Transfer factors of 137Cs, 90Sr and 40K from soil to pine needles on Jeju Island, Korea

The transfer factor (TF) is used as an important tool during environmental impact assessments. In this study, the transfer factor from soil to pine needles for radionuclides is estimated on Jeju Island, Korea. The properties of most soil of Jeju Island are those of volcanic ash soil. The activity concentrations of 137Cs, 90Sr and 40K (Bq kg−1-dry weight) have range of in soils < 1.22–38.7, 0.283–7.00 and 267–370, in pine needles 0.0798–0.289, 5.16–17.4 and 104–195. The TF (10−3 m2 kg−1-dry weight) of 137Cs, 90Sr and 40K from soil to pine needles are in the ranges of 0.0163–0.463, 8.25–51.8 and 0.633–1.91, respectively.

Soil to rice grain transfer factor and radiological dose of 137Cs and 90Sr around Narora Atomic Power Station (NAPS), Narora, India

137Cs and 90Sr concentration in rice grain and corresponding agricultural soils were measured (2009–2011) within 15 km radius of Narora Atomic Power Station (NAPS), Narora, India. 137Cs activity was in the range of BDL (<0.2)—0.65 ± 0.18 Bq kg−1 in rice grains and from BDL (<0.56)—2.06 ± 0.36 Bq kg−1 in soil samples. 90Sr content was BDL (<0.095 Bq kg−1) in all rice grain samples. Transfer factor of 137Cs from soil to rice grain was in the range of 0.10–0.40. Ingestion dose from rice consumption was significantly lesser than the permissible limits of 1.0 mSv year−1, thus posing no radiological health risk.

Transfer factor of 137Cs from soil to wheat grains and dosimetry around Narora Atomic Power Station, Narora, India

This field study was undertaken to quantify the transfer factor of 137Cs from agricultural soil to wheat grains and ingestion dose evaluation around Narora Atomic Power Station, Narora, India from 2010 to 2012. 137Cs activity was measured using NaI (Tl) well type gamma-spectrometry system. Transfer factor of 137Cs from soil to wheat grain samples was in the range of 0.12–0.46. Annual ingestion dose to man from 137Cs activity was significantly lower than permissible limit (1.0 mSv year−1). The risk measured due to 137Cs is also insignificant to members of public residing around Narora Atomic Power Station, Narora, India.

Application of PIXE analysis to investigation of plants cultivated with contaminated soil of Fukushima

We present a method to research low radioactive cesium contaminated plants by the use of PIXE analysis. Highly contaminated regions still remain in the Fukushima prefecture. We collected wild plants growing in this area, that is, Butterbur, Welsh onion, Alpine leek and White clover and measured their specific activities of 137Cs and 40K. We also measured 137Cs and 40K specific activities of soil under these plants. Soil-to-plant transfer factors of 137Cs were ∼0.02 for 4 wild plants and those of 40K were ∼0.5 except for White clover. Using PIXE analysis, we measured the concentration of mineral elements in these plants. Among mineral elements, we noted the concentrations of additional alkali metal elements such as Na, K and Rb. The experimental results showed that the concentration of Rb was proportional to the specific activities of 137Cs except for Welsh onion and other elements had no strong correlation with 137Cs. These results indicate that there may be correlations between the adsorption of Cs and Rb.

Potassium fertilization and 137Cs transfer from soil to grass and barley in Sweden after the Chernobyl fallout

Fertilization of soils contaminated by radionuclides with potassium (K) and its effect on 137Cs transfer from soil to crops is well studied in field conditions; however experiments over many years are few.The effects of potassium fertilization on cesium-137 (137Cs) transfer to hay, pasture grass, and barley growing on organic rich soils and mineral sand and loam soils in a number of field experimental sites situated in different environments in Sweden are summarized and discussed. The basic experimental treatments were control (no K fertilizers were applied), 50, 100, and 200 kg K ha−1. In the experiment, which lasted over 3–6 years, 137Cs transfer factors in control treatments ranged between 0.0004 m2 kg−1 (barley grain on sand soil) and 0.07 m2 kg−1 (pasture grass on organic rich soil). Potassium application on soils with low clay content i.e. mineral sand and organic rich soils was effective at the 50–100 kg ha−1 level. Application of 200 kg K ha−1 resulted in a five-fold reduction in 137Cs transfer for hay and up to four-fold for barley grain. The effects of potassium application were generally greater on sand than organic rich soil and were observed already in the first cut. After K application, the reduction in 137Cs transfer to crops was correlated with 137Cs:K ratios in plant material. Additional application of zeolite caused a 1.4 reduction of 137Cs transfer to hay on sand and 1.8-fold reduction on organic rich soil; whereas, application of potash-magnesia and CaO had no effect.

Comparison of transfer factors of 137Cs from soil to leafy vegetables in pot experiment and ambient environment

The paper deals with the transfer factors (TF) generated for a few varieties of leafy vegetables (spinach, fenugreek, and amaranths) consumed by the locals around Tarapur atomic power station environment in India. The soil and leafy vegetable samples collected from the ambient environment of nuclear site were used for the determination of the TFs and they were compared with TFs generated from pot experiments under controlled conditions for 137Cs. The activity of 137Cs in soil and each vegetable was determined by gamma spectrometry using HPGe detector (35 and 160% relative efficiency) and was reported on dry weight basis for both ambient environment and pot samples. The radioactive effluent containing 137Cs (pH ~7) from nuclear power station was used to spike the soil for pot (size 90 cm × 45 cm × 42 cm) experiment. The TFs obtained for ambient environment and pot experiment were found to be in the range of 0.035–0.592 and 0.0054–0.29, respectively. It is observed that TFs of ambient environment are in good agreement with those obtained in the pot experiment conducted under controlled conditions. Further, the observed TF values at Tarapur nuclear site are comparable with the range of typical IAEA transfer factor values for general leafy vegetation (0.11–2.9) for tropical environment.

Evaluation of 25 y of environmental monitoring data around Madras Atomic Power Station (MAPS), Kalpakkam, India

The Environmental Survey Laboratory at Kalpakkam, India carries out elaborate monitoring programme involving atmospheric, terrestrial and aquatic samples for radioactivity to evaluate the impact of operating two pressurised heavy water reactors. This paper presents the evaluation of 25 y (1983-2008) data. Statistical analysis of the environmental data for different radionuclides showed that the data best fits log-normal distribution. The data analysed showed that fission products such as (137)Cs, (90)Sr and (131)I were due to global fallout only. A ratio of 0.2 was obtained for (90)Sr to (137)Cs in air filter samples, only during Chernobyl accident period. The transfer factor of (137)Cs and (90)Sr for rice was computed to be 0.23 and 0.03 and vegetables 0.25 and 0.10, respectively. Activation products (3)H and (41)Ar are the only radionuclides that are related to MAPS operation. A strong correlation (r = 0.9) was observed between (3)H activity in air and (3)H discharged to the atmosphere. A similar correlation (r = 0.8) was observed in (3)H concentration in seawater and (3)H discharged in the liquid waste. The annual internal dose due to (3)H and annual external dose due to (41)Ar evaluated in the last 25 y show that the members of the public received less than 2 % of the dose limit (1 mSv y(-1)) set by ICRP 72.