Carbon is not only an essential element for life but also a key player in climate change. The radiocarbon (14C) analysis using accelerator mass spectrometry (AMS) is a powerful tool not only to understand the carbon cycle but also to track pollutants derived from fossil carbon, which have a distinct radiocarbon isotope ratio (Δ14C). Many studies have reported Δ14C of carbon compounds in streams, rivers, rain, snow, throughfall, fine particulate matter (PM2.5), and wastewater treatment plant effluents in South Korea, which are reviewed in this manuscript. In summary, (1) stream and river carbon in South Korea are largely derived from the chemical weathering of soils and rocks, and organic compounds in plants and soils, strongly influenced by precipitation, wastewater treatment effluents, agricultural land use, soil water, and groundwater. (2) Unprecedentedly high Δ14C of precipitation during winter has been reported, which can directly and indirectly influence stream and river carbon. Although we cannot exclude the possibility of local contamination sources of high Δ14C, the results suggest that stream dissolved organic carbon could be older than previously thought, warranting future studies. (3) The 14C analysis has also been applied to quantify the sources of forest throughfall and PM2.5, providing new insights. The 14C data on a variety of ecosystems will be valuable not only to track the pollutants derived from fossil carbon but also to improve our understanding of climate change and provide solutions.
A study was carried out to compare the daily foods which were eaten during 14~19 century among Korea (Chosun dynasty), China (Ming, thing dynasty), and Japan (Muromachi, Edo era). Specially, in Ming, Ching dynasty, Noodles and dumpling were cooked very often and in Muromachi, Edo era, many kinds of beans were used so much, and there were many kinds of steamed rice to compare with Korea and China. Also, in Japan at these era Woodong, Morisoba, and Somyen were used as favorite foods harbitually. 1. The crops were used as staple foods in three countries such as steamed rice, gruel, noodle, dumpling, rice cake etc. commonly. 2. In Chosun, a roe deer, deer, antelope, and wild boar were more favoite dishes than cow, chicken, and dog, generally people enjoyed to eat pork and chicken. In Ming Ching, pork, chicken, goose, dove, lamb, ass, and duck were used as food materials, also wild animals such as deer, rabbit, and monkey etc. were used. In Muromach era, wild animal as racoon dog, otter, deer, antelope, bear, were used as food materials, in early Edo era (Yayoi and Momoyama), beef and pork were used as daily foods but they were eaten decreasingly in Edo era. So in Japan at those era, the dishes prepared of fishes were more than those of meats. For example, Sushi was made from that time, people all over the world are enjoying to have Sushi at present time. 3. Also in these era, many kinds of vegetables and fruits were used in three countries, and new kinds of vegetables and fruits were introduced from foreign countries, for example, red pepper, pumpkin, sweet potato, potato in Korea, corn, sweet potato, red pepper in China, and water melon, pumpkin, corn, red pepper, marmellow, sweet potato, sugar beet in Japan.
A study was carried out to compare the food cultures among Korea (Chosun dynasty), China (Ming, thing dynasty) and Japan (Muromachi, Edo era) from 14 century to 19 century. For this study, geographical environments, historical background with the times were researched and also bibliographies related on food cultures were compared among these three countries. There were special geographical environments in three countries upon their territories and geographical features. Historically, in those era, the livelyhoods of the common people in three countries were difficult considerably because of the disturbances of war in the inside and outside of the countries. But the food cultures of three countries were changed owe to introduce the new western culture and institutions. And also there were numerous bibliographies related on food culture which were published from 14C to 19C in Chosun dynasty, Ming and Ching dynasty, and Muromachi, Edo era. They were shown to be the most in Japan, and order of China and Korea followed them. The bibliographies of Ming and thing dynasty showed less than those of Edo era for considering their population and territory, comparatively. In Japan, the biliographies related on food culture of Edo era was given the term of the age of cookery books. It was thought to be resulted from that the peoples of Japan were concerned about cooking and had more chances to contact foreign culture earlier than other country.
To analyze the radioactivity of 3H and 14C in miscellaneous radioactive wastes generated from nuclear power plants, a wet digestion method using sulfuric acid is currently used. However, sulfuric acid is classified as a special management material, and there is no disposal method for contaminated radioactive waste. Therefore, research on a thermal decomposition method that can analyze the DAW radioactive waste samples without using sulfuric acid is necessary. In this study, we will cover the final sample amount, sample injection method, and prevention of organic ignition to meet the minimum detection limit requirements of the analysis equipment. Through this research, optimal conditions for the thermal decomposition method for analyzing the radioactivity of 3H and 14C in DAW radioactive wastes generated from nuclear power plants can be derived.
Combustion method has been widely used in the analysis of 3H and 14C in various types of radioactive wastes since X. Hou reported the analysis of 3H and 14C in graphite and concrete for decommissioning of nuclear reactor. In this work, it was demonstrated that the validation result of combustion method for the simultaneous analysis of 3H and 14C in non-combustible radioactive wastes. To validate the combustion method, 3H and 14C spiked to sea sand and soil were prepared and each simulated sample was combusted with the accordance to a combustion temperature program. The validation of combustion method was assessed by the radioactivity recovery, radioactivity deviation, and relative standard deviation of measured radioactivity. The results of radioactivity recovery, radioactivity deviation, and relative standard deviation of 14C were 100~105%, less than 7%, less than 5%, respectively. In addition, 3H showed about 90% of radioactivity recovery, less than 20% of radioactivity deviation, and less than 5% of relative standard deviation. It will be provided that the validation results of combustion method in detail.
Tritium and 14C are two most important radionuclides released from nuclear facilities to the environment, and 14C contributes dominant radiation dose to the population around nuclear power plants. This paper presents an overview of the production, pathway, species and levels of tritium and 14C in nuclear facilities, mainly nuclear power plants. The methods for sampling and collection of different species of tritium and 14C in the discharge gas from the stack in the nuclear facilities, atmosphere of the nuclear facilities and environment are presented, and the features of different methods are reviewed. The on-line monitoring methods of gaseous tritium and 14C in air and laboratory measurement methods for sensitive determination of tritium and 14C in collected samples, water and environmental solid samples are also discussed in detailed. Meanwhile, the challenges in the determination and speciation analysis of tritium and 14C are also highlighted.