• Korean Journal of Environmental Agriculture
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• v.5 no.1
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• pp.48-54
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• 1986

Because of the drastic development of nuclear industries, the contamination of natural environments by the disposal of radioactive materials which are released from nuclear facilities have aroused a considerable concern in relation to agricultural practices. Therefore the present investigation, through pot experiment, was performed to find out the aspect of the uptake of $Sr^{90}$ by rice plants and its distribution in them in five different types(physicochemical and minerallogical properties) of paddy soils. The results obtained were as follows; 1) Visual toxic symptoms on the growth of rice plant due to treatment of $Sr^{90}$ up to $40{\mu}Ci/10㎏$ in a pot were not observed even though uptake of $Sr^{90}$ by rice plant was proportionally increased with the $Sr^{90}$ treatment. 2) Distribution of $Sr^{90}$ in the rice plant was the highest in the leaves (84.5%) followed in the order by stems (13.5%) and rough grain (2.0%). The ratio of $Sr^{90}$ to Ca was higher in the leaves (872) and stems (667) than in the rice grain (89). 3) $Sr^{90}$ absorption in the rice plant ranged $0.15{\sim}0.30%$ at harvesting time. Uptake of $Sr^{90}$ by rice plants decreased by the increase of soil pH and exchangeable canons in the soils, but $Sr^{90}$ uptake increased when nitrogen, organic matter and clay content in soil was high, and uptake of this nuclide in the rice plant was higher with low Illite and Vermiculite content in the soils.

• Journal of Nutrition and Health
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• v.41 no.5
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• pp.439-447
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• 2008

There is a limitation to estimate vitamin $B_{12}$ intake due to lack of data on vitamin $B_{12}$ content in many Korean foods. In this study, vitamin $B_{12}$ content was determined in some soybean or vegetable-fermented foods, edible seaweeds and other frequently consumed foods in Korea by microbioassay using Lactobacillus delbruecki ATCC 7830. The traditional type of Doenjang and Chungkookjang contained 1.85 ${\mu}g/100$ g and 0.69 ${\mu}g/100$ g of vitamin $B_{12}$, respectively, while the factory-type of Doenjang and Chungkookjang contained 0.04-0.86 ${\mu}g/100$ g and 0.06-0.15 ${\mu}g/100$ g. Vitamin $B_{12}$ was not detected in steamed soybeans and Tofu which is a not-fermented soybean product, indicating that vitamin $B_{12}$ in Doenjang and Chungkookjang might be produced during the fermentation process. The Korean-style soy sauce contained 0.04 ${\mu}g$ vitamin $B_{12}$/100 mL, but vitamin $B_{12}$ was not detected in Japanese-style soy sauce and white miso. Commercial Kimchi, a representative Korean vegetable- fermented food, made of Korean cabbage, Yeolmu, or Mustard leaves contained 0.013-0.03 ${\mu}g$ vitamin $B_{12}$/100 g, while Kimchi without red pepper and fermented fish sauce (White Kimchi) did not. Vitamin $B_{12}$ content was very high in some edible seaweeds such as laver (66.76 ${\mu}g/100$ g dry weight) and sea lettuce (84.74 ${\mu}g/100$ g dry weight), and it was 17.12 ${\mu}g/100$ g of dried small anchovy, 1.07 ${\mu}g/100$ g of whole egg, and 0.02 ${\mu}g/100$ g of coffee mix. From these results, it is assumed that Koreans take substantial amount of vitamin $B_{12}$ from plant-origin foods. And, with these data, we will be able to calculate dietary vitamin $B_{12}$ content more correctly than before. In conclusion, soybean-fermented foods, Kimchi, laver and sea lettuce are recommendable as good sources of vitamin $B_{12}$ for vegetarians or Korean elderly on grain and vegetable based diet.