• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.153-159
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• 2011

BACKGROUND: This experiment was conducted to investigate the distribution and burden characteristics of heavy metal in the rainwater sampled at Taean area, in the middle part of Korea, from April 2002 to October 2003. METHODS AND RESULTS: The relationship between concentration of heavy metal and other chemical properties in the rainwaters was also evaluated. Chemical properties in the rainwater were various differences with raining periods and years. It appeared that a weighted average pH values of rainwater was ranged from 5.0 to 5.1. Heavy metal concentrations in the rainwater were ranked as Pb > Zn > Cu > Ni > As > Cr > Cd. As compared with heavy metal concentrations of rainwater in 2002, Cu, Pb, and Zn were higher than other elements in 2003. There were positive correlation between major ionic components, such as ${NH_4}^+$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$, ${SO_4}^{2-}$ and ${NO_3}^-$, and As, Cd, Zn, Cr, and Ni concentrations in rainwater. For heavy metal distribution of rainwater, the order of average enrichment factor was Cd > Pb > As > Cu > Zn > Ni > Cr, and these were relatively higher than the natural components such as Fe, Mg and Ca. The monthly enrichment factor were relatively high, from August to October at Taean. The monthly amount of heavy metal precipitation was high in the rainy season from July to August because of great influence of rainfall. CONCLUSION(s): The results of this study suggest that the heavy metals(Cd, Pb, As, Cu, and Zn) of rainwater is strongly influenced by anthropogenic sources rather than natural sources.

• Journal of The Korean Society of Grassland and Forage Science
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• v.3 no.2
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• pp.67-76
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• 1983

This experiment was carried out to investigate the effects of the different nitrogen rates and cutting heights on the dead stubble after cutting, and the carbohydrate reserved in stubble of sorghum-sudangrass hybrid (Sorghum bicolor (L.) Moench) Pioneer 988. The experiment was undertaken in the Experimental Livestock Farm of Agriculture Coll., Seoul Nat'l Univ. In Suweon, 1981 and 1982. The results obtained are summarized as follows: 1. The dead stubble after cutting was found to be great with high rate of nitrogen fertilizer and low cutting height. It was also learned that the rainfall during forage cutting period made the dead stubble increased. 2. A significant higher (p<0.05) carbohydrate reserves in the stubble was observed in the high stubble height at the first cutting time and 6th through 7th day after the first cutting. The results indicate that the high stubble height reserves more carbohydrate for the early regrwoth stage after the first cutting when comparing with the low stubble. 3. The content of carbohydrate reserves was influenced by climete. Drought is caused to high content of carbohydrate, whereas, rain is caused to low content of that. The critical soluble carbohydrate content causing the death of stubble supposed to be 3 to 6% at least. 4. It is suggest that carbohydrate reserves in plant do not play a distinctive role for the regrowth in a summer annual forage like sorghum-sudangrass hybrid, but it might be rather influenced by the other factors, for example, environmental conditions at harvest and new bud.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.265-272
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• 1999

In this study in order to know the behavior of mineral nutrients from forage plant to soil in a grassland ecosystem, the leaching of minerals (K, Mg, Ca, N and P) from air-dried (dead) plant body was investigated by putting orchardgrass (Dactylis glomerata L.) hay on meadow during a month with seasonal changes. The results obtained were as follows; 1) The K content of the forage, not stable during the experimental seasons, tended to decrease in the summer of 1986, while the Mg and Ca contents increased in the summer. The reason might be a different response (solubility or leaching liability) of the monovalent mineral (K) and divalent ones (Mg and Ca) in the forage to rainfall. 2) The percentage of P to the initial amount in the forage showed larger decrease in a rainy period (Feb.~Mar., 1986) and during the rainy summer (May to July). The P component of the forage might be easily leached with water. 3) The percentage of the four minerals (Ca, N, Mg, K) remained the least in the period of (Jun.~Jul., 1986), 4) Though the percentage of remained Mg and N of the forage varied very similarly, the percentage of remained N was higher than that of Mg during periods before summer (January to May), while after the period the ratio of the Mg seemed to be higher than that of the N (June to December), 5) During the periods until (May~Jun., 1986) the percentage of remained K and P of the forage varied in very similar pattern, and the order of remained mineral was as follows; $Ca>N{\geq}Mg>P=K$. But from the period of (Jun-Jul) the ratio of P remained in the forage increased nearly up to the ratio of N, and the order was as follows; $Ca>Mg{\geq}N{\geq}P>K$.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.2
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• pp.151-158
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• 2011

This study was carried out in 2010 to investigate the utilization and nutritive value of native grasses, such as Phragmites communis and Miscanthus sinensis which might reduce the cost of feeding domestic cattle. The regions within the Civilian Control Line in Paju and Sihwa region in Ansan were surveyed. In Paju, the yearly silage production was 900 MT harvested from 90 ha (10 MT/ha). About 30~50% of these were sold out at the marketing price of 52,000~55,000 Won per roll (130~137.5 Won/kg). Regrown Miscanthus sinensis of 70 cm in length contained 9.6% of crude protein (CP), 82.4 of relative feed value (RFV), and 67.7% of in vitro dry matter digestibility (IVDMD). Regrown Phragmites communis of 70 cm in length contained 13.8% of CP, 84.3 of RFV, and 67.9% of IVDMD. As harvesting was delayed, the quality was decreased dramatically. In Ansan region, Phragmites communis plantation covers 100 ha. The silage production was 550 MT from the area of 50 ha (11 MT/ha) in 2009. And the marketing price was 50,000 Won per roll. But in 2010 only a small amount of grasses could have been baled due to frequent and much rainfall from spring to summer season. However, the good forage quality was observed from regrown Phragmites communis of 80 cm in length, 12.9% CP, 99.8 RFV and 66.6% IVDMD, while that of late matured grasses was very low, 2.2% CP, 52.9 RFV and 36.4% IVDMD, greatly lower than forage quality of rice straw. The quality of grasses at bloom stage of 150 cm in length was similar to that of rice straw, showing 4.5% CP, 59.9 RFV and 42.2% IVDMD. In conclusion, the overall quality of most native grasses in this survey were very poor. Therefore, we recommend that Phragmites communis and Miscanthus sinensis should be harvested during June or July to obtain better forage quality which is richer in forage values than rice straw. Production of high quality forage crops was also desirable for self sufficiency of forage.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.498-507
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• 2006

The main objective of present study was to evaluate how seasonal rainfall influenced natural habitat conditions of 10 metric habitat variables along with ionic conditions and suspended solids in the Woopo Wetland during August 2002-July 2003. Largest spatial variabilities in total suspended solids (TSS) occurred during the summer monsoon and the inorganic suspended solids (ISS), expressed as a inorganic proportion of total solids, showed linearly increasing trend from the upstream to downstream. This phenomenon was mainly attributed to counter flow of turbid water from the main Nakdong-River. During the flooding, ISS : TSS ratio showed large increases (92%) in the downstream than the upstream (43%). For this reason, transparency declined (mean=0.13 m, range=0.08-0.21 m) largely in the downstream reach and thus, chlorophyll-a concentration showed low values (range: $4.2-8.6\;{\mu}g\;L^{-1}$), indicating a direct influence on primary productivity or algal growth by inorganic turbidity. In the 2nd survey, ISS averaged 4.0 mg $L^{-1}$ (3.3-4.8 mg $L^{-1}$), thus the ISS decreased by 14 fold, compared to the ISS in the 1st survey during the flooding, while organic suspended solids (OSS) values were greater than those of ISS, indicating a dominance of organic solids. This condition was similar to solid contents in the 3rd survey, but showed a large difference compared to the 4th survey during the growing season. Habitat health assessments, based on 10 metric habitat variables, showed that QHEI values were greatest in the growing season (May) than any other seasons and largest spatial variations occurred in the 2nd survey. Overall, dataset suggest that seasonal episodic flooding during the monsoon may largely contribute nutrient cycling and sediment contents in the Woopo Wetland and Topyung Stream.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.664-671
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• 2017

Non-point source pollution is the emission source that unspecifically releases pollutants to water system from unspecific places such as cities, agricultural lands, mountains, and construction sites and its discharge path is not easily identified. Also, it is difficult to design and manage the reduction facilities for the emission quantity is primarily affected from weather conditions like rainfall. Since 2006, the significance of non-point source pollution reduction has been grown in Republic of Korea and this reinforces needs for the installation of reduction facilities. However, because the standards for the installation details and reduction efficiency are not clarified by law, people are preferring technologies that do not require particular maintenance and high expenses. The purpose of this study is to examine and maintain the efficiency of non-point source pollutants reduction facility which uses expended polypropylene as a media. The higher the depth of the media, the less range of variations in the reduction efficiency was observed and the final efficiency was also increased. When the media depth was 60 cm, the average reduction efficiency was 94% and 90% where linear velocities were 10 m/hr and 20 m/hr respectively. The results from 180 minutes operation in 10 m/hr and 20 m/hr of linear velocities were slightly different in head loss changes which were caused by media depth variations. The backwash experiments which were conducted in triplicate showed the reduction efficiency decreased as the time went on because of the media clogging. However, it was found that after the backwashing the reduction efficiency was increased as effective as the efficiency of the initial filtration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.95-100
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• 2012

This study was determined to analysis marine environmental and phytoplankton monitoring in Wando coastal waters in August during the period of 2009-2010 and provided the basic environmental data against Southwest Sea of Korea. In August, 2009, the distribution of water temperature and salinity showed an unique characteristics for all of stations, which was associated with a long duration of rainfall after July, 2009 and a lack of sunshine. In the lower of August, 2010, the stratification of water temperature and salinity was shown, which was caused by an intensive sunshine after the middle of August, 2010. Gangjin Bay and Gogeundo waters showed a highly different water temperature and transparency. It is thought that two regions have a distinct water mass and characteristics. In dissolved oxygen and oxygen saturation were higher according to higher water depth regardless of stations. In August, 2009, different dominant species occurred that Gangjin Bay showed a higher cell density of diatom, but Gonyaulax polygramma played an important role in dominant species in Gogeundo waters. It is associated with the introduction red tide water of G. polygramma occurring to southern coastal water in August, 2009. In August, 2010, diatom was extremely higher cell density compared with that of dinoflagellate that regarded as adaptive microrganism against higher quantity of suspended solid in Wando waters. Although Wando has a record of Cochlodinium red tide, this species may be difficult to grow and persist. Dominant species, diatom, play an important role in food organism for shellfish and forming a ecological lineage.

• Clean Technology
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• v.26 no.2
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• pp.151-157
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• 2020

Rapid urbanization has elevated the risk of urban flooding due to the increase in the impervious surface, causing environmental disasters and environmental pollution problems, such as lowering the groundwater level and increasing water pollution. In Korea, low impact development (LID) techniques have been introduced to minimize these environmental impacts and maintain the water cycle soundness. However, most small-scale development projects are in blind spots because there is no legal basis for rainfall runoff management. Small-scale development projects that increase the surface runoff of rainwater are required to mandate the application of LID facilities in accordance with the polluters' responsibility principle. Therefore, it is necessary to implement a preliminary consultation system for water cycle recovery. This study focuses on the cost-benefit analysis on the application of LID techniques for small-scale development projects. The scale of nationwide small-scale development projects used for cost-benefit analysis were defined as buildings with a land area of more than 1,000 ㎡ or a total floor area of 1,500 ㎡. As a result of analyzing the cost-benefits from the installation of LID facilities, they were found to be much lower than the economic standard value of 1. This might be due to the high cost of facilities compared to the scale of the project. However, considering the overall environmental value of improving the water environment and air quality by the installation of LID facilities and the publicity of reducing the operating cost of sewage treatment facilities, the introduction of a prior consultation for small-scale development projects is inevitable. In the future, institutional and financial support from local governments is required to improve the cost-benefits with the introduction of a prior consultation for small-scale development projects.

• Journal of Korea Water Resources Association
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• v.46 no.12
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• pp.1193-1207
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• 2013

Increase of impervious area caused by overdevelopment has led to increase of runoff and then the problem of flooding and NPS were brought up. In addition, as decrease of base flow made groundwater level to decline, a stream that dries up is issued. low impact development (LID) method which is possible to mimic hydrological water cycle, minimize the effect of development, and improve water cycle structure is proposed as an alternative. As introduction of LID in domestic increases, the study on small watershed is in process mainly. Also, analysis of property of hydrological runoff and load on midsize watershed, like sewage treatment district, is required, the study on it is still insufficient. So, area applying LID practices from watershed of Dongrae stream is pinpointed and made the ratio and then expand it to watershed of Oncheon stream. Among low impact development practices, Green Roof, Porous Pavement, and Bio- retention are selected for the application considering domestic situations and simulated with SWMM-LID model of each watershed and improvement of water cycle and reduction of non-point pollution loads was analysed. Improvement of water cycle and reduction of non-point pollution loads were analyzed including the property of rainfall and soil over long term simulation. The model was executed according to scenario based on combination of LID as changing conductivity in accordance with soil type of the watershed. Also, this study evaluated area of LID application that meets the efficiency of conventional management as a criteria for area of LID practices applying to sewer treatment district by comparing the efficiency of LID application with that of conventional method.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.4
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• pp.271-278
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• 2004

This paper shows our experiment is performed to understand the exposure tendency of $^{137}Cs$ according to the height of area and also, to supplement it by considering chemical characters of $^{137}Cs$ exposed to the soil. The samples we use for this experiment are from the general flat area of Yeonggwang county where it has NPPs, the high places of Keumjung & Bulgap mountains, and Naejan mountain where it is quite far from the NPPs. The data from this experiment show that the exposure of $^{137}Cs$ is not harmful since its range is around 252 Bq/kg-dry in most of sampled soils such as from the general flat area, the high place of Keumjung mountain where is 2 km away from the NPPs, the other high place of Bulgap mountain where is about 20 km away from the NPPs, and Naejan mountain where it is far from the NPPs. Not like the general flat area, however, the data show that the higher the area is the more $^{137}Cs$ is exposed. That is, at the top of mountains, the more $^{137}Cs$ is exposed compared to at the bottom area. It is almost $2{\~}6$ times more than the general flat area of Yeonggwang county where it has NPPs. The data also show that the spread of $^{137}Cs$ is deeply related to the geographical(the height of area, rainfall, etc..) factors and chemical factors of soils. As the geographical factors, there are far more chances to be exposed of $^{137}Cs$ at the high area of mountains through the air compared to at lower area and therefore, we can get more high-leveled readings of $^{137}Cs$ at the high area while it is low-leveled ones at the general flat area even if both of them have the same soil conditions. Regarding the chemical factors of soil, it is clarified that the CEC is the key factor. The CEC means the capability of sticking $^{137}Cs$ accumulated into the soil. Hence, the more CEC it has the more high-leveled readings of $^{137}Cs$ we get under the same geographical condition.