• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.216-227
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• 2008

To understand eutrophication in the upper regions of brackish Lake Sihwa with a limited water exchange, temporal and spatial distributions of pollutants in water and sediment were investigated from March to October in 2005 and 2006. Also, pollution levels of water and sediment were estimated by trophic state index (TSI) and sediment quality guideline (SQG). Total nitrogen (TN), total phosphorus (TP), organic matter (COD), and chlorophyll $\alpha$ (Chl-$\alpha$) concentrations in the surface waters were largely varied temporally and spatially, and the variations were highest in the middle areas where strong halocline was formed. Chl-$\alpha$ concentrations in the middle area were very high in April (>$900\;{\mu}g\;L^{-1}$) when algal blooms (red tides) occurred. The relationships between TN and Chl-$\alpha$ (r=0.31), and TP and Chl-$\alpha$ (r=0.65) indicated that the algal growth was primarily affected by phosphorus rather than nitrogen. The distribution of COD was similar to that of Chl-$\alpha$, indicating that the autochthonous organic matters may be a more important carbon source, especially in the middle areas. The brackish water regions were classified as eutrophic or hypertrophic based on their TSI values ($69{\sim}76$). In addition, the content of nutrients (especially TP) in surface sediments were classified as severe polluted state, except the upper areas. Major causes of the eutrophication observed were probably due to high nutrients loading from watersheds, the phosphorus release from anaerobic sediment, and long retention time by the limited water exchange through the sluice gates.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.247-256
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• 2012

Stable carbon isotope ratio of oil components are known to be unaffected by weathering processes and thus has been widely used to determine the origin of spilled oil. In this study, molecular index and composition of stable carbon isotope in 15 crude oils and petroleum product were analyzed and used as oil fingerprints to determine the discriminating power of each fingerprinting method among target crude oils. Through the fingerprints of alkane distribution only Bintulu and B-C(1%) were distinguishable from other crude oils. The pristane/phytane ratio can classify the crude oils into three groups but differentiation of crude oils within a group was impossible using the ratio. The crude oils of A.L., A.S.L., Foroozan and B-C(1%) were differentiated from the other oils using PAH source recognition indexes of C2D/C2P and C3D/C3P. The usage of 4-mD/1-mD and 2/3-mD/1-mD ratio was able to distinguish A.S.L., Bintulu and Oman from the other crude oils. However the PAH source recognition ratios in the other crude oils were similar and thus they were impractical to be used for source identification among the target crude oils. Stable carbon isotope ratios of alkanes were able to uniquely specify each crude oil in the plot of ${\delta}^{13}C_{C21}$ and ${\delta}^{13}C_{C25}$ except A.L., A.M., Qatar-Marine, B-C(1%). The oil fingerprinting method using stable carbon isotope ratios of individual alkane compounds showed more discriminating power among the target crude oils than the conventional source recognition indexes of PAHs or alkanes.

• The Journal of Korean Physical Therapy
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• v.8 no.1
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• pp.21-32
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• 1996

This study was conducted in an attempt to grasp the health problems and environmental situation of the farmers and their vinyl houses. The study was done between Aug. 10, 1995 and Sep. 10, 1995, for one month period. with two hundred and nine vinyl house cultivation farmers chosen at random as subjects in five areas in and around Kim Chun City. The following are the results of the study carried out through direct interviews and surveys with the subjects : 1. The career of farming on vinyl house facilities by sex(male vs female) averages 17.29 and 15.08 years is shorter than that of general farmer's average of 31.24 and 25.58 years(P<0.05). Hours of labor between the two are silimar : monthly labor hours for vinyl house farmers are average 28 and 27.52 days. longer than the general farmers' average of 26.57 and 25.95 hours respectively. 2. The comp aints of physical symptoms among the vinyl house farmers range from lumbago, shoulder pain dullness in the limbs and dizziness, which show no remarkable differences from those of general farmers. 3. The frequency of application of chemicals on vinyl house forming for a period of one year averages 23.79, three times as often as the general farmer's average or 8.36(P<0.05). In the addiction rate of chemicals, too, the vinyl house farmer stowed a higher percentage of $9.09\%$ over the general farmer's $1.24\%$(P<0.01). 4. In temperature, humidity and disconfort indices of in and outside of the vinyl house, room temperature is on an average $34.6{\pm}5.05^{\circ}C,\;11.7^{\circ}C$ higher than that of outside, while in humidity inside was lower than outside by $10.6\%$ point, $65.9\%$ over $76.5\%$. The discomfort index was higher inside by $83{\pm}4.61\;vs\;70.64{\pm}5.61$. 5. The status of physical treatment over the past one year shows : for vinyl house farmers-physiotheraphy$(43.06\%)$, pharmacy$(24.04\%)$, clinic(18.66%), herbal medicine(574%) : for general farmers-pharmacy$(34.16\%)$, Physiotherapy$(27.33\%)$, Clinic$(18.63\%)$, Folk Medicine$(11.18\%)$ (P<0.01).

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.165-175
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• 2018

The purpose of this study is to provide the basic data such as distribution status, growth characteristics, and the structural characteristics of forest stands for the systematic conservation and management of relict forest trees (stem girth of 300cm or larger) established naturally in Gangwon Province, Korea. The survey showed that 434 individuals of 19 species (conifers: 228 individuals of 4 species, broad-leaved trees: 206 individuals of 15 species) were distributed in Gangwon Province, and Taxus cuspidata was the most abundant among them with 203 individuals or about 46.7 % of the total. The stem girth was average of 404cm (conifers: 373cm, broad-leaves: 421cm), and Tilia amurensis with multi-stemmed growing on Sorak mountain range had the largest stem girth at 1,113cm. The average height and the crown width of relict forest trees were 15.4m and 10.0m, respectively. Although the environments of relict forest trees showed a slight difference by species, the relative appearance frequencies of most trees were high in the environments where the altitude was higher than 1,000 m, slope degree was greater than $25^{\circ}$, the slope faced north, and microtopography was at the upper of slopes. Regarding the stand characteristics of relict forest trees per unit area ($/100m^2$), the average total coverage was 294% (max. 475%), the total average number of species was 36 species (max. 60 species), the average species diversity index (H') was 2.560 (max. 3.593), the average canopy closure was 84.8% (max. 94.6%), and the average basal area (/ha) was $52.7m^2$ (max. $116.4m^2$, relict trees $30.0m^2$, and other trees $22.7m^2$). The analysis of the dynamics of the forest stands where relict forest trees were growing showed four types of the maintenance mechanisms of relict forest trees depending on the supply pattern of succeeding trees: "Low-density but persistent type (Quercus mongolica, Abies holophylla, Tilia amurensis, and Pyrus ussuriensis)," "Long ago stopped type (Pinus densiflora)," "Recently stopped type (Abies nephrolepis, Quercus variabilis, and Betula schmidtii)," and "Periodically repeated types of supply and stop (Salix caprea and Quercus serrata).".

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.395-407
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• 2002

A 3D hydrodynamic-ecological coupled model was applied to estimate a food supply to oysters in Geoje-Hansan Bay where is one of the oyster culturing sites in Korea, In this study, the primary productivity (PP) was adopted as an index of food supply, and the spatial patterns of average chlorophyll a concentration during a culturing seasons from September to May of the following year were simulated by the model, The numerical result showed that PP was high in the inner part of the bay and the adjacent areas of Hwado island, but low in the outer. This result indicates that PP is essentially influenced by anthropogenic nutrient loadings in the system. The model was calibrated using the field data in May which is non culturing season of oysters and a simulated phytoplankton biomass agreed fairly well with the observed data ($R^{2}=0.70$, $RE=10.3\%$). The computed food supply varied from 0.19 to $1.27\;gC/m^{2}/day$ with a mean value of $0.62 gC/m^{2}/day$ from September to May. The highest value was showed in May ($1.27 gC/m^{2}/day$) and the lowest was in February ($0.19 gC/m^{2}/day$).

• Korean Journal of Environment and Ecology
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• v.27 no.1
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• pp.99-112
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• 2013

This study aims to show the changes of characteristics of vegetation structure for 20 years(1991~2010) in Naejangsan National Park. As a result of analysis of actual vegetation, the mixed community of Quercus variabilis and Quercus serrata was distributed with 56.1%, and Q. variabilis community showed in southern steep slope with 17.6%. Pinus densiflora community(5.8%) was observed on the ridge and Carpinu tschonoskii community distributed in the slope of the valley with 6.6%. Zelkova serrata and Prunus sargentii community were distributed in valley. The classification by TWINSPAN, ordination by DCA considering importance percentage and property of vegetation class were divided into 4 communities, which are community I(P. densiflora-Q. variabilis community), community II(Q. variabilis community), community III(C. tschonoskii community) and community IV(Mixed deciduous broad-leaved trees community). The age of Pinus densiflora was 32years old and Q. serrata was 36 years old in the community I, that of Q. variabilis was 64 years old in the community II, Q. serrata was 46 years old and C. tschonoskii was 45 years old in the community III, and Acer palmatum was 54 years old and Cornus controversa was 47 years old in the community IV. As the result of Shannon's index of species diversity, the community Iwas ranged from 0.9751 to 1.4199, community II was ranged from 1.0765 to 1.3278, community III was ranged from 1.0353 to 1.2881, and community IV was ranged from 1.1412 to 1.3807. The change of vegetation structure analyzed through the comparison with results of studies carried out 20 years ago were natural selection of P. densiflora, expansion of Quercus spp. and increase of C. tschonoskii. Especially, A. palmatum is dominated by Q. variabilis in canopy layer like the result of study 20 years ago. A. palmatum was analysed by 14.6% in the canopy layer of only mixed deciduous broad-leaved trees community. As a result of analysis of habitat property of Q. variabilis and A. palmatum, Q. variabilis was distributed in dry area with the low value of pH, O.M., exchangeable cations and Avail. P, and A. palmatum was located in the wet valley with huge value of nourishment. The tendency of reduction of bio-diversity by Sasa borealis is same as previous study but, the distributed areas were reduced in Naejangsan area.

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.87-94
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• 2011

To find the preliminary environmental conditions for a short-time transport of living olive flounder, Paralichthys olivaceus, the stress response and physiological metabolic activity of the cultured fish to feed deprivation and slow temperature descending ($15.8^{\circ}C{\rightarrow}13.3^{\circ}C$) were monitored for 8 days. The monitored variables were the plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), glucose (GLU), total protein (TP), electrolytes ($Na^+$, $K^+$, $Cl^-$) and thyroid hormones ($TT_4$, $TT_3$, $FT_4$ and $FT_3$). In food deprivation experiment for 8 days, we did not find any statistical change of level in AST, ALT and electrolytes ($Na^+$, $K^+$, $Cl^-$), but found a significant decrease in TP and GLU. In thyroid hormones, the levels of four hormones in plasma were all showing a tendency to decrease. Especially, $FT_4$ and $TT_3$ were significantly decreased, indicating a withering of physiologic activity. In the temperature test, although no any significant change in AST, TP and electrolytes ($Na^+$, $K^+$, $Cl^-$), we observed a significant decrease of ALT and GLU following to temperature descending from $15.8^{\circ}C$ to $13.3^{\circ}C$ (P<0.05). In the levels of thyroid hormones, any significant change was not observed for experimental period. We conclude that the stress response and physiological activity of olive flounder were more influenced by feed deprivation than slow temperature descending at a transport of living fish, and plasma GLU appears to be sensitive factor to physiological metabolic activity, indicating that it could be used as a monitering mark or index for a health inspection of the fish.

• The Korean Journal of Soil Zoology
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• v.6 no.1_2
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• pp.25-31
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• 2001

Oribatid mite communities in the process of litter decomposition were analyzed In Korean pine (Pinus koraiensis) forests of Namsan and Kwangreung, which were supposed to be under different environmental selective pressures. Oribatid mites were collected bimonthly from the litter bags (mesh size 0.4 mm, 1.7 mm) which was set up in the forest floor of study sites. This study had been carried out from Jan., 1997 to Sept., 1998. Species abundance of Kwangreung (mesh size 1.7 mm) was significantly higher than that of Namsan (mesh size 1.7 mm), but total no. of species did not exceed 30 species in all study sites. Concerning body length, medium sized oribatid mites (0.3-0.7mm) were more abundant than small ( < 0.3 mm) and large ( > 0.7 mm) sized mites. In Kwangreung, species whose body lengths were 0.2 mm to 0.5 mm were major group. However, a little larger species than Kwangreung's major group were dominant in Namsan. Sorenson similarity index and cluster analysis suggested that there were qualitative and quantitative differences in species composition in Namsan and Kwangreung. More species were collected in May through September than the other sampling times, but the pattern was rather different between first year and second year. Newly immigrant species were high in May in the first year and many of them regained on next year. Diversity indices suggested that species diversity of Kwangreung was higher than that of Namsan. Nearly 70% of total individual abundance was occupied by several dominant species in Namsan and Kwangreung . In the litter bags of mesh size 1.7 mm, the most dominant species was Trichogalumna nipponica in Namsan and Kwangreung, but in the litter bags of mesh size 0.4 mm in Kwangreung it was Ramusella sengbuschi which is smaller than T. nipponica. And important species related to litter decomposition were selected as follows; T. nipponica, Epidamaeus coreanus, Scheloribates latipes, Ceratozetes japonicus, Ramusella sengbuschi, Eohypochthonius crassisetiger, and Cultroribula lata.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.374-383
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• 2019

The Wangpo stream located in the Buyeo-gun was a small stream with both low water quality and quantity due to the cultivated land and settlement area through the stream. In order to restore ecosystem, the Sustainable Structured wetland Biotop system was applied to treat 1,500 to 7,000 ㎥/d amount of effluent water pumped from the Buyeo sewage treatment plant facility as well as inflowed from nonpoint pollution source of Wangpo stream. As a result of continuous monitoring for 2 years from 2016 to 2018 after completing restorative construction, the average BOD₅ as an index of organic pollution was 7.3 mg/L and the average effluent concentration became 2.1 mg/L, showing an improvement by 71.2%. The average inflow concentration of T-N was 7.953 mg/L and the average outflow concentration was 3.379 mg/L, showing 57.5% of improvement. The average inflow concentration of T-P was 0.177 mg/L and the average outflow concentration was 0.052 mg/L, showing about 70.7% improvement. The results of ecological monitoring after creating biotope by reuse of treated waste water and nonpoint pollution source of the Wangpo Stream are as follows. The plant taxa founded in water SSB(Sustainable Structured wetland Biotop) system of the Wangpo Stream was total 41 species in 21 families, showing a higher proportion of naturally introduced plant than that of artificially planted species. In case of other terrestrial animals, both amphibian and reptile group were confirmed as 3 species in 6 families, avian group was 25 species of 15 families, and mammal group observed 5 species in 5 families, respectively. All species have been created and enhanced through purified water inhabited in the SSB(Sustainable Structured wetland Biotop) system as a treatment wetland, eventually migrating to the Wangpo Stream.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1523-1528
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• 1999

The consumer's demands for minimally processed fruits and vegetables have been increased rapidly because of its convenient handling, fresh-like quality as well as producing less wastes from the environmental point of view. Asian pears which are one of the main fruits widely produced and consumed in Korea easily lost their characteristics due to browning and softening after cutting. The objective of this study is to investigate the effects of various treatments on delaying deterioration of sliced Asian pears. 'Shingo' pear slices were treated with various solutions $(1%\;NaCl,\;0.2%\;L-cysteine,\;1%\;CaCl_2\;or\;1%\;calcium\;lactate)$ and were packaged with low density polyethylene $(LDPE,\;60\;{\mu}m)$, ceramic $(CE,\;60\;{\mu}m)$ or vacuum $(Ny/PE,\;80\;{\mu}m)$ film at $20^{\circ}C\;and\;0^{\circ}C$. In order to evaluate the quality of packaged sliced pears, quality index was determined in terms of color, firmness, soluble solids, titratable acidity. ascorbic acid, changes of gas composition, microbial test, and sensory quality. The results showed that sliced 'Shingo' pears packaged with CE and vacuum film maintained better quality than with LDPE at $0^{\circ}C\;and\;20^{\circ}C$. To retard browning and softening. 0.2% L-cysteine and 1% NaCl solutions applied for 1 minute were effective to reduce surface browning of sliced pears, and 1% $CaCl_2$ was the most effective to prevent softening.