• Title, Summary, Keyword: Sr-90 concentration

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A Study on Distribution of Cs-137 and Sr-90 in Soils around Taejon Region (대전지역 토양에 대한 Cs-137 및 Sr-90 방사능농도 분포 조사)

  • Lee, Myung-Ho;Lee, Chang-Woo;Hong, Kwang-Hee;Choi, Yong-Ho;Kim, Sang-Bok;Park, Doo-Won;Lee, Jeong-Ho
    • Journal of Radiation Protection and Research
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    • v.20 no.2
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    • pp.123-128
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    • 1995
  • The concentration of Cs-137 and Sr-90 has been analyzed in soils around Taejon region. A correalation was found between the concentration of Cs-137 and the organic matter content. The mean value of Cs-137 was 14.37Bq/kg-dry and that of Sr-90 was 7.95Bq/kg-dry in undisturbed soils around Taejon region. The concentration ratio of Cs-137/Sr-90 was 1.99. The distribution of Cs-137 and Sr-90 was similar to cumulative fallout level and had been more affected by nuclear weapons test than by the chernobyl accident.

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Sr-90 Uptake by the Barley (Hordeum vulgare L. emend. Lamark) and Soil-to-Plant Transfer Coefficient (보리의 토양 Sr-90 흡수 및 토양 - 작물체 전이계수)

  • Choi, Yong-Ho;Chung, Kyu-Hoi;Chun, Ki-Jung;Kim, Sam-Rang;Lee, Jeong-Ho
    • Journal of Radiation Protection and Research
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    • v.16 no.1
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    • pp.33-42
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    • 1991
  • A pot experiment on the Sr-90 uptake by the barley from a loamy-sandy soil of pH 6.05 treated with Sr-90 and slaked lime was carried out in a green house. The rate of Sr-90 uptake at maturity was, on an average, 0.41% for a naked barley Neolssalbori and 0.23% for a covered one Olbori. Transfer coefficients of Sr-90 for the former were higher than those for the latter by about 30-60% depending on the plant parts. There were, on the whole, not significant differences in the rate and in the coefficient among Sr-90 concentration treatments. Slaked lime addition equivalent to about 94kg/10a was not effective for lessening Sr-90 uptake or diminishing Sr-90 transfer coefficient. As transfer coefficients, 1.51, 4.45, 0.35, and 1.30, on the dry weight basis, could be proposed for the stem, leaf, seed, and whole top of the barley, respectively. Growth inhibition or yield decrease due to Sr-90 uptake was not observed.

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Uptake and Accumulation of Soil Strontium-90 by Peanut and Sesame (토양 strontium-90의 땅콩과 참깨에 의한 흡수 및 축적)

  • Choi, Yong-Ho;Jo, Jae-Seong
    • Korean Journal of Environmental Agriculture
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    • v.15 no.1
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    • pp.11-18
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    • 1996
  • A greenhouse experiment on the Sr-90 uptake by peanut and sesame was conducted through pot cultures on a sandy loam soil of pH 6.35 treated with Sr-90 in 5.2 and 31.2Bq per gram. The rate of Sr-90 transfer from soil to each plant part, the ratio of Sr-90 concentration in the part to the concentration in soil, and the patterns of their temporal changes were not, on the whole, significantly different between the two treatments. About 0.7 and 0.5 % of Sr-90 in soil transferred to all the mature plants of peanut and sesame, respectively, with the radioactivities in their roots not counted. Only 4% and less than 15% of Sr-90 absorbed by peanut and sesame, respectively, translocated to their seeds. Both crops showed the highest Sr-90 concentration in the leaf and the lowest in the seed. At maturities, the concentration ratio in dry seed was 0.4 in peanut and 3.3 in sesame and that in dry leaf was 12.5 and 10.7, respectively. Sr-90 concentrations in the top 15 cm soil after harvests averaged about 80 % of the concentrations at starting. Sr-90 uptake resulted in neither growth inhibition nor yield decrease.

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Predictions of $^{90}Sr$ and $^{137}Cs$ Concentrations in Rice Seeds and Chinese Cabbage after a Nuclear Accident (원자력 사고후 쌀알과 배추내 $^{90}Sr$$^{137}Cs$ 농도 예측)

  • Choi, Yong-Ho;Lim, Kwang-Muk;Hwang, Won-Tae;Lee, Han-Soo;Lee, Chang-Woo
    • Journal of Radiation Protection and Research
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    • v.27 no.3
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    • pp.127-146
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    • 2002
  • A method of more realistically, predicting radionuclide concentrations in crop plants varying with time after a nuclear accident was established to estimate 50 years' concentrations of $^{90}Sr$ and $^{137}Cs$ in polished rice seeds and Chinese cabbage for unit dry deposition. After non-growing season accidents, concentrations of both nuclides decreased gradually with time and $^{90}Sr$ concentrations were higher than those of $^{137}Cs$ throughout the whole period. Radionuclide concentrations in the 1 st year after growing season accidents were on the whole higher than those after non-growing season accidents by factors of up to 30 for $^{90}Sr$ and up to 1,000 for $^{137}Cs$. In polished rice seeds, the 50 years-integrated concentration was higher for $^{90}Sr$ than for $^{137}Cs$ after non-growing season accidents, whereas the opposite was true after growing season accidents. In Chinese cabbage. however, it was higher for $^{90}Sr$ than for $^{137}Cs$ after both types of the accident. Generally speaking, the dominant pathway for the integrated concentration after the growing season accident was root uptake for $^{90}Sr$ and direct plant contamination for $^{137}Cs$. The effect of resuspension was negligible. Based on the predicted results. the direct]on of planning countermeasures was suggested for various accident conditions.

Distributions of 137Cs and 90Sr in the Soil of Uljin, South Korea (울진토양에서의 137Cs 및 90Sr 분포)

  • Song, JiYeon;Kim, Wan;Maeng, Seongjin;Lee, Sang Hoon
    • Journal of Radiation Protection and Research
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    • v.41 no.1
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    • pp.49-55
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    • 2016
  • Background: For the purpose of baseline data collection and enhancement of environmental monitoring the distribution studies of $^{137}Cs$ and $^{90}Sr$ in the soil of Uljin province was performed and the relation between surface soil activities and soil properties (pH, TOC and median of the surface soil) was analyzed. Materials and Methods: For 14 spots within 10 km from the NPP surface soil samples were collected and soils for depth profile were sampled for 3 spots in April 2011. Using ${\gamma}$-ray spectrometry with HPGe detector, the concentrations of $^{137}Cs$ were determined and the concentrations of $^{90}Sr$ were measured by counting ${\beta}$-activity of $^{90}Y$ (in equilibrium with $^{90}Sr$) in a gas flow proportional counter. Results and Discussion: The concentration ranges of $^{137}Cs$ and $^{90}Sr$ were $<0.479-39.6Bq{\cdot}(kg-dry)^{-1}$ (avg. $7.51Bq{\cdot}(kg-dry)^{-1}$) and $0.209-1.85Bq{\cdot}(kg-dry)^{-1}$ (avg. $0.74Bq{\cdot}(kg-dry)^{-1}$) which were similar to the reported values from other regions in Korea. The activity ratio of $^{137}Cs$ to $^{90}Sr$ in surface soils was around 9.67, which is much bigger than the initial value of 1.75 for worldwide fallouts because of faster downward movement of $^{90}Sr$ after fallout than that of $^{137}Cs$. For depth profile studies soils were collected down to 40 cm depth for the locations of Deokgu, Hujeong and Maehwa. The $^{137}Cs$ concentration distribution of the first two showed maximum values at top soils and decreased rapidly in exponential manner, while $^{90}Sr$ showed two local maximum values for soils near top and about 30 cm depth. Through linear fittings between the $^{137}Cs$ and $^{90}Sr$ concentrations of surface soil and pH, TOC and median of the surface soil, the only probable relationship obtained was between $^{137}Cs$ and TOC (determination coefficient $R^2=0.6$). Conclusion: The concentration ranges of $^{137}Cs$ and $^{90}Sr$ in Uljin were similar to the reported values from other regions in Korea. The only probable relationship obtained between activities and soil properties was between $^{137}Cs$ and TOC.

The Uptake and Loss of Strontium-90 by the Seaweed Undaria pinnatifida (미역에 의한 스트론튬-90의 농축 및 잔류)

  • Byung-Sun Yoo;Koon-Ja Lee;Su-Rae Lee
    • Nuclear Engineering and Technology
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    • v.14 no.3
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    • pp.116-121
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    • 1982
  • The uptake and retention of strontium-90 from seawater by the seaweed Undaria pinnatifda(sea mustard) varied depending on the plant part, exposure time, salinity, contents of stable strontium and calcium, and presence of chelating agent in the seawater. The concentration factors attained at equilibrium were in the range of 50 and it was evident that the bioaccumulation was largely due to the adsorption of the radionuclide on the surface of seaweed.

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Studies on the Separation and Concentration Method of $^{90}Sr$ in the Environmental Samples (환경시료 중 $^{90}Sr$의 분석을 위한 분리농축법 연구)

  • Won, Mi Sook;Cho, Kyu Bong;Yoon, Jang Hee;Lee, Dae Won;Shim, Yoon Bo
    • Analytical Science and Technology
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    • v.14 no.1
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    • pp.8-14
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    • 2001
  • New process to determine $^{90}Sr$ in the environmental samples was established by investigating the existing methods. The environmental samples included soil, milk, seaweed, fishes and clams, pine needles, and marine sediment. Using the developed method combined with fuming nitric acid and ion exchange resin, which could be reduced the treatment step, we could be removed Ca effectively for the determination of $^{90}Sr$. The recovery yield of $^{90}Sr$ in this method was 10% higher than those of using the fuming nitric acid only. This method could be applied to all environmental samples we choose. The content of $^{90}Sr$ in soil was the highest value in the tested environmental samples.

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Activity Concentrations of 137Cs and 90Sr in Seawaters of East Sea, Korea

  • Lee, Hae Young;Kim, Wan;Kim, Yong-Hwan;Maeng, Seongjin;Lee, Sang Hoon
    • Journal of Radiation Protection and Research
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    • v.41 no.3
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    • pp.268-273
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    • 2016
  • Background: This study was a long-term evaluation of $^{137}Cs$ and $^{90}Sr$ activity concentrations in seawater samples from the East Sea, Korea, in order to establish current activity levels. Results and long-term monitoring trends will be useful in the future monitoring of environmental radioactivity. Materials and Methods: Surface seawater samples were collected quarterly from Guryongpo and Jangho in the East Coast between 1998 and 2010 and the quarterly deep seawater samples were collected from three sites in the sea adjacent to Ulleung-do between 2012 and 2015. The activity concentrations of $^{137}Cs$ were measured using a gamma-spectrometer. The activity concentrations of $^{90}Sr$ and $^{90}Y$ in a radioactive equilibrium state were measured using a gas flow proportional counter. Results and Discussion: We found the annual average activity concentrations of $^{137}Cs$ in the surface seawater was $1.66-2.89mBq{\cdot}kg^{-1}$ in Guryongpo and $1.68-2.43mBq{\cdot}kg^{-1}$ in Jangho. The annual average activity concentrations of $^{90}Sr$ in the surface seawater was $0.83-1.98mBq{\cdot}kg^{-1}$ in Guryongpo and $0.82-1.57mBq{\cdot}kg^{-1}$ in Jangho. The annual average activity concentrations of $^{137}Cs$ in the deep seawater sites were $1.51-1.73mBq{\cdot}kg^{-1}$, $1.19-1.60mBq{\cdot}kg^{-1}$ and $0.87-1.15mBq{\cdot}kg^{-1}$ in TH, JD, and HP. The annual average activity concentrations of $^{90}Sr$ in the same deep seawater sites were $1.00-1.94mBq{\cdot}kg^{-1}$, $0.82-1.26mBq{\cdot}kg^{-1}$, and $0.79-1.32mBq{\cdot}kg^{-1}$. The effective half-life was calculated by analyzing change over time in the activity concentration in the surface seawater. The effective half-life of $^{137}Cs$ was $15.3{\pm}0.1years$ in Guryongpo and $102{\pm}3years$ in Jangho. The effective half-life of $^{90}Sr$ was $28.3{\pm}4.3years$ in Guryongpo and $16.6{\pm}0.1years$ in Jangho. The ratio of the average activity concentration ($^{137}Cs/^{90}Sr$) was 1.72 in the surface seawater, which is similar to the reported ratio of the global radioactive fallout. The ratio in the deep seawater was 1.24, which is somewhat low compared to the global ratio (1.6, 1.8). Conclusion: Activity concentrations of $^{137}Cs$ and $^{90}Sr$ in the seawaters of the East Sea were similar to the previously reported activity levels in the East Sea and northwestern Pacific as a result of global radioactive fallout following atmospheric nuclear weapon tests.

Fallout Radioactivity in Korean Foodstutts (Part 4) Stronitium-90 in Liquid Whole Milk Produced in Korea (한국식품 중의 방사능 함량 (제4보) 한국 우유의 스트론튬-90 함량)

  • Yang Kyung Rin
    • Journal of the Korean Chemical Society
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    • v.13 no.2
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    • pp.181-186
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    • 1969
  • The concentration of Strontium-90 in liquid whole milk produced in Korea were measured during past four years. The samples of milk were purchased from dairies in Seoul. Strontium-90 was analysed radiochemically and the amount of stable calcium was also determined. Radioactivity of Yttrium-90 was counted in low background beta counter which has the background of 1.38 cpm. The concentrations of Strontium-90 in the milk are 25.1 PCi $^{90}Sr$/g.Ca in 1965, 26.8 PCi $^{90}Sr$/g. Ca in 1966, 13.7 PCi 90Sr/g.Ca in 1967 and 18.2 PCi $^{90}Sr$/g.Ca in 1968 in annual average. The concentrations of Strontium-90 in the milk of 1967 and of 1968 were decreased approximately compared with the values of 60% 1965 and 1966. From the results we can see that Strontium-90 concentrations in the milk vary roughly proportionally with the specific activity of fallout. Considering on the safety problems, the Strontium-90 levels in the milk produced in Korea were far below the maximum permissible level recommended by ICRP.

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Distribution and characteristics of radioactivity$(^{232}Th,\;^{226}Ra,\;^{40}K,\;^{137}Cs\;and\;^{90}Sr)$ and radiation in Korea

  • Yun, Ju-Yong;Choi, Seok-Won;Kim, Chang-Kyu;Moon, Jong-Yi;Rho, Byung-Hwan
    • Journal of Radiation Protection and Research
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    • v.30 no.4
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    • pp.167-174
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    • 2005
  • The concentrations of natural and artificial radionuclides in soil and gamma ray dose rate in air at 233 locations in Korea have been determined. The national mean concentrations of $^{232}Th,\;^{226}Ra,\;^{40}K,\;^{137}Cs\;and\;^{90}Sr$ in soil were $60{\pm}31,\;33{\pm}14,\;673{\pm}238,\;35{\pm}9.3\;and\;5.0{\pm}3.4\;Bq\;kg^{-1}$, respectively. The mean gamma-ray dose rate at 1 m above the ground was $7918\;nGy\;h^{-1}$. $^{137}Cs$ concentration had highly significant correlation with organic matter content and cation exchange capacity. $^{90}Sr$ concentration had slightly coherent with pH. The results have been compared with other global radioactivity and radiation measurements.