• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.321-337
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• 2010

Long-term trends and distribution patterns of water quality were investigated in the Mokpo coastal areas of the Yellow Sea, Korea from 1979 to 2009. Water samples were collected at 5 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids (SS), chemical oxygen demand (COD), dissolved oxygen (DO) and nutrients. Spatial distribution patterns of temperature, pH and DO were not clear among stations but the seasonal variations were distinct except ammonium. The trend analysis by principal component analysis (PCA) during 30 years revealed the significant variations in water quality in the study area. Spatial water qualities were discriminated into 3 clusters by PCA; station cluster 1, 2~4, and 5. Annual water qualities were clearly discriminated into 4 surface water clusters and 2 bottom water clusters by PCA. By this multi-variate analysis, the annual trends were summarized as the followings; water temperature, pH and COD tended to increase from late 1980's, salinity to decrease, phosphate to increase from 1994 and dissolved inorganic nitrogen to increase, due to the input of fresh water same as shown in Kyoungin coastal area, Asan coastal area, Choensoo bay and Gunsan coastal area.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.8
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• pp.1069-1075
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• 2009

Conger eel (Conger myriaster) is used as a well-being food in the foodservice industry in Korea. We analyzed not only the proximate composition but also the taste components affecting conger eel, which are fatty acids, nucleotides, amino acids, etc. Concerning the composition, the crude lipid was the lowest in summer at 3.2%, which is considered due to spawning period. The major fatty acids were $C_{16:0},\;C_{16:1},\;C_{18:0},\;C_{18:1},\;C_{20:5},\;and\;C_{22:6}$. The $C_{18:1}$ content was the highest among the fatty acids and the content varied between 36.76 and 45.11% by season. Seasonal change in the content of poly-unsaturated fatty acids was increased from spring to winter in conger eel. Among the nucleotides, the contents of IMP (3.617$\sim$5.524 $\mu$mol/g) and Hx (0.913$\sim$2.238 $\mu$mol/g), which is closely related to taste, and the concentrations of IMP and Hx were the highest (7.219 $\mu$mol/g) in winter, and HxR (0.625$\sim$1.652 $\mu$mol/g) was higher than ATP (0.058$\sim$0.083 $\mu$mol/g), ADP (0.145$\sim$0.161 $\mu$mol/g), and AMP (0.166$\sim$0.179 $\mu$mol/g). In conger eels, the major total and free amino acids were glutamic acid (14,178.7$\sim$7,802.6 mg%), aspartic acid (4,669.2$\sim$8,259.0 mg%), lysine (4,198.3$\sim$7,540.8 mg%), leucine (3,843.6$\sim$6,782.1 mg%), and histidine (199.6$\sim$644.4 mg%), glycine (94.8$\sim$152.2 mg%), alanine (35.3$\sim$71.2 mg%), glutamic acid (44.1$\sim$70.6 mg%), respectively, but the concentration of amino acids was different by season. The content of free amino acids, which is related to the taste component, was detected as high in summer and winter at 1179.2 and 1,605.2 mg%, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.141-149
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• 1993

The seasonal variation of lipid content was mostly attributed to diet, water temperature and period of reproduction etc. The lipid mainly consisted of neutral lipid and phospholipid. Nonpolar lipid content was higher in between late spring and summer, while polar lipid content lower during the period. The composition of neutral, glyco, and phospholipid of the total lipid: in average was 53.88, 10.09 and $36.03\%$, respectively. The neutral lipids were composed of triglycride($51.88\%$) and free sterol($23.21\%$) as major component and a little quantity of diglycerides, monoglycerides, esterified sterols and hydrocarbon, free fatty acid were also identified. The phospholipids of each fraction were mainly occupied by phosphatidyl choline($55.5\%$), followed by phosphatidyl ethanolamine($27.8\%$), phosphatidyl inositol($8.65\%$) and phosphatidyl serine($4.85\%$). The major fatty acids of the total lipid in ascidian were $C_{20:5},\;C_{22:6},\;C_{16:6}\;and\;C_{18:1}$, respectively. The fatty acid composition of phospholipid and neutral lipid showed a similar tendency to that of the total lipid. The major fatty acids in the fraction of glycolipid, however, appeared $C_{16:0},\;C_{20:1},\;C_{18:0}\;and\;C_{18:1}$ in order.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.203-218
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• 2011

Long-term trends and distribution patterns of water quality were investigated in the Yeoja Bay of South Sea, Korea from 1976 to 2010. Water samples were collected at 3 stations and physicochemical parameters were analyzed including water temperature, salinity, hydrogen ion concentration (pH), dissolved oxygen (DO), chemical oxygen demand (COD), suspended solids (SS) and nutrients. Spatial distribution patterns of temperature, pH and DO were not clear among stations but the seasonal variations were distinct except ammonium. The trend analysis by principal component analysis (PCA) during 31 years revealed the significant variations in water quality in the study area. Spatial water qualities were discriminated into 2 clusters by PCA; station cluster 1 and 2~3. Annual water qualities were clearly discriminated into 4 clusters by PCA. By this multi-variate analysis, the annual trends were summarized as the followings; water temperature, COD and SS tended to increase from late 1970's, decreased salinity, and increased phosphate from 1991 to 2001 and increased dissolved inorganic nitrogen. Water quality was showed by the input of fresh water same as those of Kyoungin coastal area, Asan coastal area, Choensoo bay, Gunsan coastal and Mokpo coastal area in the Yeoja Bay.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.60-71
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• 2007

Groundwater from public wells was monitored during one year with two month interval for hydrogeochemical parameters and chlorofluorocarbons (CFCs) as environmental tracers in Jeju Island. Concentrations of major cations and $SiO_2$ show variation less than 10% whereas $NO_3$ and dissolved oxygen (DO) showed larger variation though DO variation did not change oxic or suboxic condition. $NO_3$ concentration has no consistent seasonal pattern with the largest variation of 35%. Groundwater ages determined by CFCs became temporarily younger by 5 years in October for groundwater with ages of 15 to 25 years, which can be attributed to infiltrating water in rainy season. Compared to air temperature, groundwater temperature has much smaller variation with no phase difference, which can be accounted for by a two-component model consisting of infiltrating water from surface and deeper groundwater with negligible temperature variation. The relatively small variation in groundwater age and temperature indicates that groundwater recharge through fast flow-paths is much smaller compared with basal groundwater in terms of aquifer storage.

• Journal of Environmental Health Sciences
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• v.38 no.3
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• pp.233-240
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• 2012

Objectives: The changes in atmospheric $PM_{2.5}$ concentrations were extensively studied in one metropolitan city (Incheon), two small and medium sized cities (Gunsan, Cheonan), and a rural area (Gosan in Jeju). The concentrations of heavy metals (Cr, Mn, Fe, Ni, Cu, Zn, Al, Pb) and the component features of $PM_{2.5}$ were determined for these areas. Methods: This study sampled $PM_{2.5}$ at the designated locations in the metropolitan (Incheon), small and medium sized cities (Gunsan in Jeonbuk and Cheonan in Chungnam), and rural area (Gosan in Jeju) to investigate concentrations with a sampling device (Sequential sampler, APM Eng., Korea). Sampling was undertaken over months, from June 26 to November 26, 2009. Sampling was conducted a total of 44 times, with routine sampling at intervals of six days (24 total times) and intensive sampling (20 total times) during the summer and fall. Mass concentration of $PM_{2.5}$ was evaluated and the concentrations of heavy metals (Cr, Mn, Fe, Ni, Cu, Zn, Al, Pb) were analyzed. Results: The geometric average of concentrations of $PM_{2.5}$ per district was $35.289{\mu}g/m^3$ for Cheonan, $29.955{\mu}g/m^3$ for Incheon, $24.119{\mu}g/m^3$ for Gunsan, and $18.773{\mu}g/m^3$ for Jeju, respectively. The average concentration of $PM_{2.5}$ in Cheonan was the highest. The seasonal concentration distributions per district showed Cheonan $33.387{\mu}g/m^3$, Incheon at $31.550{\mu}g/m^3$, Gunsan $22.900{\mu}g/m^3$, and Jeju $18.900{\mu}g/m^3$ in the summer. For the autumn, the concentrations were $36.873{\mu}g/m^3$ in Cheonan, $28.625{\mu}g/m^3$ in Incheon, $25.227{\mu}g/m^3$ in Gunsan, and $18.667{\mu}g/m^3$ in Jeju. According to the collected data, the concentration showed a tendency to rise during the autumn in all of these regions with the exception of Incheon. For heavy metal distribution per district, Fe showed an elevated concentration during the summer while high concentrations of Pb and Zn occurred during the autumn. Conclusion: These results demonstrated that atmospheric factors affected the concentrations of heavy metals. The results of this study could be used as foundational data for setting environmental air standards focusing on a $PM_{2.5}$ receptor.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.377-384
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• 2012

This study was carried out to evaluate effect of temperature condition on nitrogen mineralization of organic matter, distribution of microbial group by PLFA profiles, and soil microbial community in non-volcanic ash soil. Dried soil 30 g mixed well each 2 g of pellet (OFPE) organic fertilizers, pig manure compost (PMC), and food waste compost (FWC). And then had incubated at $10^{\circ}C$, $20^{\circ}C$, and $30^{\circ}C$, respectively. Nitrogen mineralization rate increased with increasing temperature and that was in the order of FWC>OFPE>PMC. Distribution ratio of microbial group by PLFA profiles showed that was different significantly according to incubation temperature and the type of organic matter. As incubating time passed, density of microbial group decreased gradually. The Gram-bacteria PLFA/Gram+ bacteria PLFA, Fungi PLFA/Bacteria PLFA, and Unsaturated PLFA/saturated PLFA ratios were decreased according to the increasing temperature gradually. Principal component analysis using PLFA profiles showed that microbial community structures were composed differently by temperature factor at both 75 days ($10^{\circ}C$) and 270 days ($30^{\circ}C$). In conclusion, Soil microbial community structure showed relative sensitivity and seasonal changes as affected by temperature and organic matter type.

• Journal of Environmental Impact Assessment
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• v.17 no.5
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• pp.311-320
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• 2008

Reusing livestock manure have various advantages in securing soil organic resources, and since the costs needed for converting them into liquefied fertilizers are relatively moderate compared to normal treatment, such methods are necessary. In this study, the Recycling Capacity Assessment of Gyeonggi-do was carried out by comparing between the fertilizer demands for specific crops based on the cultivation areas and the amount of fertilizer resources that are generated from livestock manure. From this assessment, the possibility of obtaining resources by converting livestock manure into fertilizers were evaluated. The amount generated of Livestock Manure in Gyeonggi-do were evaluated by applying the emission units to the number of livestock manure. And from the amount generated of Livestock Manure, the amount of fertilizer produced from Livestock Manure were calculated by using the fertilizer a component rate. When considering the amount of fertilizer produced from Livestock Manure based on the type of livestock, N 6,626 ton/year, $P_2O_5$ 1,824 ton/year, $K_2O$ 4,480 ton/year were produced from milk cow manure, while N 5,247 ton/year, $P_2O_5$ 2,772 ton/year, $K_2O$ 2,879 ton/year, were produced from beef cattle manure. N 14,924 ton/year, $P_2O_5$ 7,205 ton/year, $K_2O$ 6,750 ton/year were produced from pigs and N 12,651 ton/year, $P_2O_5$ 4,458 ton/year, $K_2O$ 5,542 ton/year were produced by chickens. So the total amount of fertilizers that can be obtained from livestock manure were 3,668 ton/year Nitrogen, 16,259 ton/year phosphate and 19,651 ton/year kalium. And the total fertilizer demands in Gyeonggi-do were Nitrogen 27,200 ton/year, Phosphate 8,853 ton/year, and kalium 13,211 ton/year respectively. Nitrogen which had higher demands than production quantities were considered as limitation factors in crop growth. So the Recycling Capacity Assessment was carried out mainly based on Nitrogen. Since the Nitrogen quantities that can be provided by recycling livestock manure were 3,532 ton/year lesser than the Nitrogen demands, it is estimated that it would be desirable to convert livestock manure into resources. But in order to properly convert the entire livestock manure into organic resources, the seasonal situation that effects the nitrogen demands of crops along with the regional effects due to the industrial structures should be seriously analyzed. In addition, a system that can effectively produce and manage fertilizer should be established.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.368-377
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• 2012

This study evaluated the water quality of Yeongsan River by multivariate analysis using the data collected during 2001~2010. Water quality in Yeongsan River could be explained up to 75.2% by four factors, which were included in loading of nutrients (32.021%) and organic matters (17.453%), seasonal variation (14.775%) and microbes (10.951%). The results of cluster analysis were classified into three groups by factor 1 and 2, which has different water quality characteristics. Group 1 included sampling stations located in the upper stream and estuary dyke of Yeongsan River, group 2 included Gwangju 1 and Gwangsan affected by domestic sewage of Gwangju-cheon, and group 3 included sampling stations located in the midstream around the livestock farm and farmland.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.99-104
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• 2010

This study was conducted to investigate the physiological activities of extracts from Suaeda japonica harvested in different season for its possibility as a functional material in food or cosmetic composition. The total mineral content of S. japonica harvested in summer was about 89.8 g/kg, and it comprised a little more content than one in winter (86.7 g/kg). The Na content of S. japonica did not show a remarkable contrast on harvest season whereas the K and Ca contents of summer were decreased to half or increased to double in winter. In addition, the antioxidative activity of each extract from S. japonica changed depending on harvest season. For S. japonica harvested in summer, the ethyl acetate extract showed the highest DPPH radical scavenging activity, but in winter the butanol extract fraction had the highest value. However, FRAP values were the highest in butanol extracts from S. japonica harvested in summer and winter. Total phenolic contents in the extracts were in proportion to the antioxidative activities. From the tyrosinase inhibition assay and melanogenesis with B16BL6, the hexane extracts from both seasons had shown the highest whitening effects. These results suggest that the extraction methods should be optimized depending on harvest season to utilize the S. japonica as functional component source.