• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.29-36
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• 2013

The objective of the research was to describe the effect of straw mat cover and soil amendments on the reduction of runoff and non-point source load from steep sloped highland agricultural fields. Four $5{\times}30$ m plots on sandy loam soil with 28 % slope were prepared. Experimental treatments were bare (control), rice straw mat cover (3,000 kg/ha) (S), PAM (5 kg/ha)+Gypsum (1 ton/ha) (PG) and rice straw mat cover+PAM+Gypsum (SPG). A variety of lettuce was cultivated and runoff was monitored during a growing season in 2011. Natural monitoring was conducted to three times. Runoff rate of S, PG and SPG plots were significantly lower than those of control plot. Especially, the runoff rate is zero in SPG plot at a first rainfall events. The reduction rate of runoff from the S, PG and SPG plots was 30.8 %, 29.0 % and 81.8 % compared to control plots, respectively. The reduction rate of NPS pollution load of S, PG and SPG was ranged of 50~90 %, 30~70 % and 90~100 %, respectively. Yield of lettuce from S, PG and SPG plots was respectively 400 (567 kg/ha), 320 (453 kg/ha) and 760 (1,067 kg/ha) that of compared to control plots greater than that from control plots (140 kg/ha). We speculated that the experimental treated plots could hold more nutrients and moisture than the control and helped the crop grow healthier. When analyzing the above results, in terms of reduction of runoff and NPS pollution load and crop yields, SPG experimental treatment had the best effect. It was concluded that the use of rice straw mats cover and soil amendments on soil surface could not only reduce the NPS pollution loads in receiving waters but also help increase the crop yield.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.356-365
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• 2002

One of the most important factors that cause eutrophication is nutrient materials containing nitrogen and phosphorus which stem from excreation of terrestial sources and release from sediment. Therefore, to improve water quality, the reduction of these nutrients loads should be indispensible. At this study, the three-dimensional numerical hydrodynamic and ecosystem model, which was developed by Institute for Resources and Environment of Japan, were applied to analyze the processes affecting the eutrophication. The residual currents, which were obtained by integrating the simulated tidal currents over 1 tidal cycle, showed the presence of a typical counterclockwise eddies between Gyewha and Garyuk island. Density driven currents were generated westward at surface and eastward at the bottom in Saemankeum area where the fresh waters are flowing into, The ecosystem model was calibrated with the data surveyed in the field of the study area in annual average. The simulated results were fairly good coincided with the observed values within relative error of $30\%$. The simulations of DIN and DIP concentrations were performed using ecosystem model under the conditions of $40\~100\%$ pollution load reductions from pollution sources. In study area, concentration of DIN and DIP were reduced to $59\%$ and $28\%$ in case of the $80\%$ reduction of the input loads from fresh water respectively. But pollution loads from sediment had hardly affected DIN and DIP concentration, The $95\%$ input load abatement is necessary to meet the DIN and DIP concentration of second grade of ocean water quality criteria.

• Journal of Environmental Impact Assessment
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• v.19 no.1
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• pp.83-89
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• 2010

The areas for agricultural purposes in Korea are decreasing every year because of urbanization. However, it is still 17.6% of the total national boundary on 2008. Most of the rice paddy fields are located near the waterbodies which require lots of water during rainy season from May to September. Also lots of nitrate and phosphate chemical fertilizers are spread on the fields every year in order to supply the nutrients for vegetation. The excess nutrients is impairs the water quality of rivers and lakes when it is washed out from the fields. The Korean Ministry of Environment (MOE) adapted the new water quality improvement program, which is the Total Daily Maximum Load, to improve the water quality and to protect the aquaecosystems. The constructed wetland is one of the possible ways to treat the agricultural runoff. The constructed wetland on this study area was constructed by MOE in 2007 to evaluate the application of the constructed wetlands. Plant growth continues to increase during the summer until it reaches its highest biomass of 6,032 g/$m^2$ in August and September. More researches about sedimentation, vegetation, water balance, etc. were performed to evaluate the removal efficiency, to find the removal mechanisms and to make the guidelines for design and maintenance.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.216-225
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• 2018

Over the past 40 years, the public sector has continued to invest in the sewage treatment plants (STPs) in Korea. Currently, the domestic sewage treatment rate is over 90% with the enhancement of operating efficiency of the STPs, and water quality of major rivers has been continuously improved. However, COD and T-N indicators are stagnating or slightly worsening, and though advanced treatment facilities are installed in most of the STPs, there is a limit to the removal of nutrients. Since there are a lot of water pollution sources in the vicinity of the watershed because of high population density in Korea, it is essential to reduce the inflow of the nutrients in order to prevent the eutrophication of the rivers and lakes. While the effluent T-P standard in STPs has greatly strengthened since 2012, which results in the considerable investment for the improvement of treatment process in STPs for the last few years, it is necessary to strengthen the T-N standards, as the effluent standard of T-N has been maintained at 20 mg/L since 2002. In this study, based on the analysis of the effluent T-N standard status of major industrialized countries, and the domestic nitrogen load in public waters, the option of appropriate T-N standard level is reviewed, and the required investment costs and the effect of strengthening the standard are estimated.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.342-348
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• 2006

Changes in water quality and algal growth according to the differences in the inflow volume were investigated in the Daecheong Lake from 1998 to 2001. Until year 2000, inflow volume considerably depended on the rainfall throughout the basin. However, the correlation was low since 2001 when water storage in the upstream Yongdam Lake was started. According to inflow volume-TP relationship analyses, significant correlation was found at up- and middle-stream sites, excluding down-stream site of the Daechong Lake. For chlorophyll-a, correlation was found with flow volume at all sites except for Choo-So. In a dry year, although nutrients loads were relatively lower than those in rainy years, there were higher concentrations of chlorophyll-a and massive bloom of Microcystis. Limiting factors for algal growth seems to be not the volume of nutrients load but retention time and physical disturbance of the water body influenced by inflow volume. Thus, in the Daecheong lake, it would be more important to focus on the management of eutrophication in dry years than in rainy ones.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.5
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• pp.763-772
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• 2018

Objective: Swine manure in Korea is separated into solid and liquid phases which are composted separately and then applied on land. The nutrient accumulation in soil has been a big issue in Korea but the basic investigation about nutrient input on arable land has not been achieved in detail. Within the nutrient production from livestock at the national level, most values are calculated by multiplication of the number of animals with the excreta unit per animal. However, the actual amount of nutrients from swine manure may be totally different with the nutrients applied to soil since livestock breeding systems are not the same with each country. Methods: This study investigated 15 farms producing solid compost and 14 farms producing liquid compost. Composting for solid phase used the Turning+Aeration (TA) or Turning (T) only methods, while liquid phase aeration composting was achieved by continuous (CA), intermittent (IA), or no aeration (NA). Three scenarios were constructed for investigating solid compost: i) farm investigation, ii) reference study, and iii) theoretical P changes (${\Delta}P=0$), whereas an experiment for water evaporation was conducted for analyzing liquid compost. Results: In farm investigation, weight loss rates of 62% and 63% were obtained for TA and T, respectively, while evaporation rates for liquid compost were 8.75, 7.27, and $5.14L/m^2{\cdot}d$ for CA, IA, and NA, respectively. Farm investigation provided with the combined nutrient load (solid+liquid) of VS, N, and P of 117.6, 7.2, and $2.7kg/head{\cdot}yr$. Nutrient load calculated from farm investigation is about two times higher than the calculated with reference documents. Conclusion: The nutrient loading coefficients from one swine (solid+liquid) were (volatile solids, 0.79; nitrogen, 0.53; phosphorus, 0.71) with nutrient loss of 21%, 47%, and 29%, respectively. The nutrient count from livestock manure using the excretion unit has probably been overestimated without consideration of the nutrient loss.

• Journal of Nutrition and Health
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• v.30 no.1
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• pp.100-108
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• 1997

Our current food hygiene law mandates nutrition label (NL) for the special nutrition foods, health support foods, instant foods, and foods with certain nutrient emphasized note, only. Currently more processed foods are bearing nutrition labels though the format is quite inconsistant. This study examined the status on current nutrition labeling practices for the processed foods that are retailed in the supermarket. The obtained information was assessed in the aspects of numerical data presentation on nutrients content, descriptive terms, health claim, and the format. The results are summarized as follows. 1) Foods with NL are limited to the food category specified by current hygiene law while voluntary nutition labeling is few. 2) Descriptive terms such as free, low, and sufficient are not substantiated with quantitative data. The efficacy of microelements which has not been clalified yet are overemphasized but major nutrients are ignored. 3) The regulations for the descriptive terms are set on the base of the nutrient content per 100g or 100ml under current nutrition labeling act. It would mislead consumers thus the definition for these descriptor be better set on the unit of the amount of food customary eaten at one time. For this the standard serving size should be set officially. 4) Quantitative nutrition information given on food products is difficult to compare because of the lack in formality. The title of NL, load and kinds of nutritents, order of nutrients listed, the unit of expression, RDA comparision, and reference RDA are inconsistant among the foods similar in dietary property. Uniform format is needed to give NL the credibility and usefulness. Proividing nutrition information to the consumers with NL is a worldwide practice though its efficacy has been controversial. Under newly legistered health promotion law in Korean nutrition education is esxpected to take part in to improve national nutrition condition and NL would education is expected to take part in to improve national nutrition condition and NL would be a potent tool for public nutritions education. It appears to be the time to mandate NL to all the processed foods in the market. The result of present study would initiate further consumer experiments related to NL. Various interest groups such as food and nutrition professions, public health organizations, government regulatory agencies, food producers and marketers, and consumer groups need to particepate and communicate for the legislation of NL and the development of NL format.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.255-268
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• 2012

Nonpoint source pollution has become a concern for water quality in the Han River system, especially during the high runoff events during the monsoon season. The patterns in nonpoint source runoff the relationships with land use, rainfall intensity, and stream nutrients concentrations were surveyed in 19 streams in the Han River watershed. The results show that the magnitude of NPS inputs of nutrients and sediment in the Han River watershed are of a serious concern. In the South Han River watershed, event mean concentrations (EMC) for biochemical oxygen demand (BOD), suspended sediment (SS), dissolved organic carbon (DOC), dissolved total phosphorus (DTP), total nitrogen (TN) Nitrate ($NO_3$-N) and total phosphorus (TP) were $1.94mg{\cdot}L^{-1},\;251mg{\cdot}L^{-1},\;2.75mg{\cdot}L^{-1},\;0.076mg{\cdot}L^{-1},\;2.82mg{\cdot}L^{-1},\;2.40mg{\cdot}L^{-1}$ and $0.232mg{\cdot}L^{-1}$, respectively. In the North Han River watershed, EMCs for BOD, SS, DOC, DTP, TN, $NO_3$-N and TP were $1.34mg{\cdot}L^{-1},\;172mg{\cdot}L^{-1},\;2.63mg{\cdot}L^{-1},\;0.032mg{\cdot}L^{-1},\;1.97mg{\cdot}L^{-1},\;1.55mg{\cdot}L^{-1}$ and $0.148mg{\cdot}L^{-1}$, respectively. The specific export coefficients of nutrient and sediments were much higher than those of other reports. Our study also found that the proportion of agricultural field area was significantly correlated with the EMCs for nutrients. Therefore, efforts to reduce NPS loading must focus on agricultural practices in the watershed. The relationships between land use and nutrient and sediment export found in this study can be used to derive estimates of runoff coefficients for agricultural field and as input data for modeling works and to develop total maximum daily load and best management practices in the Han River watershed.

• Journal of Environmental Science International
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• v.3 no.3
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• pp.185-195
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• 1994

Masan bay is one of the polluted enclosed bays, which has red tides problem and the formation of oxygen deficient water in the bottom layer. Most important factors that cause eutrophication and red tide is nutrient materials containing nitrogen and phosphorus which stem from terrestrial sources and nutrients released from sediment. Therefore, to improve of water quality, reduction of these nutrient loads should be indispensible. At this study, the three-dimensional numerical hydrodynamic and eutrophication model, which were developed by Institute for Resources and Environment of Japan, were applied to analyze the processes affecting the phytoplankton production and also to evaluate the effect of water quality improvement plans on phytoplankton production. In field sorvey, the range of concentrations of chlorophyll-a at surface area was found to be 29.17 - 212.5mg/m3, which were exceeding eutrophication criteria. The constant currents defined by integrating the simulated tidal currents over 1 tidal cycle showed the counterclockwise eddies in the southern part of Budo. The general directions of constant currents were found to be southward at surface and northward at bottom over all the bay. The eutrophication model was calibrated with the data surveyed in the field area in June, 1993. The calculated results are in fairly good agreement with values within relative error of 30%. The pollutant load from the sources such as the input from terrestrial release from the sediment was reduced by the rate of 50, 70, 90, 98% to effect of phytoplankton production. Phytoplankton production was reduced to of the 90% reduction of the input loads from terrestrial sources and 8% in 90% reduction of the load from sediment.

• Korean Journal of Veterinary Service
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• v.15 no.2
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• pp.203-214
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• 1992

Livestock waste causes ground and surface water pollution, eutrophication of reservoir as well as adverse affects living environment of those who dwell nearby. In order to investigate the pollution load from livestock waste, physical and chemical characteristics of the waste were determinded in the survey of livestock farms. Once pollution load is obtained as a function of the origin units of livestock, the influence of livestock waste on the Daecheong reservoir was studied. 1. For Daecheong reservoir inflow area, the liverstock manure productions of beef cattle swine, dairy cattle and chicken were 1,135.6t/day, 480t/day, 241.3t/day, 48t/day respectively； Beef cattle was the mai or source of the pollution. Pollution loading productions due to the livestock waste around the were found to be 53.31t/day for BOD, 222.49t /day for COD, 261.99t/day for T-S, 9.64t/day for T-N, 6.54t/day for T-P 2. Bocheong stream turnd out to be the major contribution for pollution loading production to Daecheong reservoir with 10,748kg /day of BOD, 47,157kg /day of COD, 1,946kg /day of T-N, 1,271kg /day of T-p. 3. Actual pollution loadings from livestock wastes for the area of Daecheong reservoir were estimated as 1,997kg /day(BOD), 8,546kg /day(COD), 364kg /day(T-N), 243kg /day (T-P), respectively Therefore, advanced treatment for livestock waste is recommended for Daectleong reservoir inflow area to eliminate the nutrients which are major sources of eutrophication of the reservoir.