• Journal of Food Hygiene and Safety
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• v.21 no.4
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• pp.231-237
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• 2006

Nowadays the teabag is worldwide used for various products including green tea, tea, coffee, etc. since it is convenient for use. In case of outer packaging printed, however, there is a possibility that the plasticizers which is used for improvement in adhesiveness of printing ink may shift to inner tea bag. In this study, in order to monitor residual levels of plasticizers in teabags, we have established the simultaneous analysis method of 9 phthalates and 7 adipates plasticizers using gas chromatography (GC). These compounds were also confirmed using gas chromatography-mass spectrometry (GC-MSD). The recoveries of plasticizers analyzed by GC ranged from 82.7% to 104.6% with coefficient of variation of $0.6\sim2.7%$ and the correlation coefficients of each plasticizer was $0.9991\sim0.9999$. Therefore this simultaneous analysis method was showed excellent reproducibility and linearity. And limit of detection (LOD) and limit of quantitation (LOQ) on individual plasticizer were $0.1\sim3.5\;ppm\;and\;0.3\sim11.5\;ppm$ respectively. When 143 commercial products of teabag were monitored, no plasticizers analysed were detected in filter of teabag products. The migration into $95^{\circ}C$ water as food was also examined and the 16 plasticizers are not detected. In addition we carried out analysis of heavy metals, lead (Pb), cadmium (Cd), arsenic (As) and aluminum (Al) in teabag filters using ICP/AES. $Trace\sim23{\mu}g$ Pb per teabag and $0.6\sim1718{\mu}g$ Al per teabag were detected in materials of samples and Cd and As are detected less than LOQ (0.05 ppm). The migration levels of Pb and Al from teabag filter to $95^{\circ}C$ water were upto $11.5{\mu}g\;and\;20.8{\mu}g$ per teabag, respectively and Cd and As were not detected in exudate water of all samples. Collectively, these results suggest that there is no safety concern from using teabag filter.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.336-349
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• 1986

This study was conducted to examine the plant succession on the improved pasture of the mountain districts around Mt. Halla in Cheju Island. For this study, the researcher had investigated for ten years the improved pasture which had been used for grazing from 1976 to 1985. The pasture was reclaimed from native grassland. The mixed seeds of 17kgs' Dactylis glomerata, 7kgs' Festuca arundinacea, 2kgs' Lolium multiflorum and 2kgs' Trifolium repens were sowed per ha. The results of this study are the followings; The annual changes in the number of plant species were observed. 37 weed species were found in 1976 and increased year after year to 151 species in 1985. The changes in the distribution of annual and perennial plant, and one species of arbor were found in 1976 and increased respectively year by year to 56 species (annual plant), 95 species (perennial plant) and 9 species (arbor) in 1985. The average plant height of introduced grasses by year increased from 38.05cm (1976) to 47.30cm (1978) and decreased from 40.50cm (1979) to 10.36cm in 1985 (y =-0.501x$^2$+1.609x + 41.946). While the average plant height of invading weeds increased from 26.61cm to 42.84cm (y=-0.80$\chi$$^2$＋2.540$\chi$＋27.570) between 1976 and 1985. The density of introduced grasses was 70.90% in 1976 and was reduced to 0.49% in 1985 (y =-0.501$\chi$$^2$+1.609$\chi$+41.946); while that of introduing weeds was 29.10% in 1976 and was increased to 99.51% in 1985 (y=-0.080$\chi$$^2$＋2.540$\chi$＋27.570). The coverage of introduced grasses by year increased gradually from 72.8% (1976) to 74.86% (1978) and decreased from 43.01% (1979) to 1.21% in 1986 while that of intruding weeds developed a tendency to increase every year. Their coverage in 1976 was 22.09% and increased to 98.78% in 1985. The weight of introduced grasses by year increased from 2,808kg (1976) to 3,535kg (1978) per l0a and after 1979 decreased gradually from 2,326kg (1978) to 35kg per l0a in 1985. That of intruding weeds increased yearly from 308kg in 1976 to 3,178kg in 1985. The type of annual vegetation were changed as follows; Year Type 1976-1978 Dactylis glomerata / Trifolium repens type 1979 Trifolium repens / Imperata cylindrica type 1980-1982 Imperata cylindrica / Zoysia Japonica type 1983 Imperata cylindrica / Pteridium aquilinum type 1984-1985 Imperata cylindrica / Miscanthus sinensis type The plants whose plant height, coverage, density, and weight increased year after year were Imperate cylind-rica, Zoysia japonica, Pteridium equilinum, Miscanthus sinensis, Cirsium japonicum, Erigeron canadensis, Artemisia japonica, Lespedeza cuneata, Spondiopogon cotuUfer. Cymbopogon tortilis, Plantago asiatica, Rumex acetosella, etc. The vegetation of Digitaria sanguinalis, Hydrocotyl japonica, Artemisia asiatica, etc. was com-paratively remarkable in the beginning.