• Economic and Environmental Geology
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• v.26 no.1
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• pp.41-54
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• 1993

The Ulsan Fe-W deposit, which can be classified as a calcareous skarn deposit, is represented by ore pipe consisting principally of magnetite and lesser amounts of scheelite with minor sulphides, sulphosaits, arsenides, sulpharsenides, etc. At Ulsan mine, metasomatic processes of skarn growth may be divided broadly into two stages based on the paragenetic sequence of calc-silicate minerals and their chemical composition; early and late skarn stages. Early stage has started with the formation of highly calcic assemblages of wollastonite, diopsidic clinopyroxene and nearly pure grossular, which are followed by the formation of clinopyroxenes with salite to ferrosalite composition and grandite garnets with intermediate composition. Based on these calc-silicate assemblages, the temperatures of early skarn formations have been in the ranges of $550^{\circ}$ to $450^{\circ}$. The calc-silicate assemblages formed during the earlier half period of late skarn stage show the enrichment of notable iron and slight manganese, and the depletion of magnesium; clinopyroxenes are hedenbergitic, and grandite garnets are andraditic. The formation temperatures during this skarn stage are inferred to have been in the range of $430^{\circ}$ to $470^{\circ}C$ at low $X_{CO_2}$ by data from fluid inclusions of late andraditic garnets. The later half period of late skarn stage is characterized by the hydrous alteration of pre-existing minerals and the formation of hydrous silicates. The main iron-tungsten mineralization representing prominent deposition of magnetite immediately followed by minor scheelite impregnation has taken place at the middle of early skarn stage, while complex polymetallic mineralization has proceeded during and after the late skarn stage. Various metals and semimetals of Fe, Ni, Co, Cu, Zn, As, Mo, Ag, In, Sn, Sb, Te, Pb and Bi have been in various states such as native metal, sulphides, arsenides, sulphosaits, sulpharsenides and tellurides.

• Economic and Environmental Geology
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• v.51 no.3
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• pp.279-289
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• 2018

With the launch of the new government in 2017, National Planning and Advisory Committee (NPAC) announced the five-year plan for the government administration and the 100 national tasks. The Ministry of Science and ICT (Information & Communication Technology) (MSIT) and other government agencies issued work plans for 2018, including R&D plans. Analyzing the changes in government policy will be a major task of public research and development institutions. This study analyzed the changes of the R&D policy of the new government and the R&D policy direction and strategic plan of the government departments related to the geoscience and mineral resources in 2018. The results of the analysis are as follows: 1) to lead the innovation growth through the 4th industrial revolution, 2) to supply clean energy and to cope with climate change in the environment and energy field, 3) to improve the quality of life through problem solving in the life of the people and disaster prevention. Considering the investment direction of the government, it is necessary to lead the geoscience and mineral resources R&D to solve problems of the society and to grow by the science and technology.

• Korean Journal of Environmental Agriculture
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• v.10 no.1
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• pp.77-83
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• 1991

An animal experiment was performed to investigate the effects of dietary cadmium on growth rates and cadmium accumulations in internal organic tissues and blood by feeding mice with dietary $cdcl_2$ additives and/or brown rice with high cadmium content as during a 12-week feeding period. The results were as follows : Mice weights decreased with increasing levels of dietary cadmium at the end of a 9-week feeding period. The weights of mice organs in the cadmium-free feeding group were higher than in the cadmium-added groups, and the weights of mice organs did not show any significant differences among feeding groups with different levels of dietary cadmium. The concentrations of cadmium in kidney and liver were much higher than in other internal organs and blood, and the next higher concentration was in the heart. The cadmium accumulation in all internal organs and blood increased with increasing dietary cadmium levels, respectively. The ratios of cadmium accumulation in organ tissues and total blood of cadmium-added groups increased with decreasing dietary cadmium levels.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.108-113
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• 1983

There has been two kind of research fields in evaluating the ecotoxicity of chemicals The one is a bioassay and the other is an ecosystem analysis. The toxicants are transported into different biota, which have quite different environmental behaviour patterns and toxic properties. The effects of pesticides (butachlor, carbofuran, and tricyclazole) on periphyton community was studied by analyzing content of chlorophyll-a and autotrophic index (AI) that is a means of determining the trophic nature of the periphyton community. Results indicated that the content of chlorophyll-a was not influenced by the pesticides. The growth of algae was inhibited by sunshine period. And AI value is 43-2027: the large value indicates heterotrophic periphyton community, and was not affected by pesticides.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.83-89
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• 2002

The effect of low dose $\gamma$ radiation on photosynthesis and the reduction of photoinhibition in red pepper plant was investigated. The seedling height leaf width and leaf length of pepper were stimulated in plants grown from seeds irradiated with the low dose of 4 Gy. The $O_2$ evolution in the 4 Gy irradiation group was 1.5 times greater than in the control. To investigate the effect of low dose $\gamma$ radiation on response to high light stress, photoinhibition was induced in leaves of pepper by illumination of high light (900 $\mu mol/m^2/s$). Pmax was decreased with increasing illumination time by 20% in the control, while hardly decreased in the 4 Gy irradiation group. The photochemical yield of PSII, estimated as Fv/Fm, was decreased with increasing illumination time by 50% after 4 hours while Fo did not change. However, Fv/Fm in the 4 Gy irradiation group was decreased by 37% of inhibition, indicating that the photoinhibition was decreased by the low dose $\gamma$ radiation. Changes in the effective quantum yield of PSII, $\Phi_{PSII}$, and 1/Fo-1/Fm, a measure of the rate constant of excitation trapping by the PSII reaction center, showed similar pattern to Fv/Fm. And NPQ was decreased after photoinhibitory treatment showing no difference between the control and the 4 Gy irradiation group. These results showed the positive effect of low dose $\gamma$ radiation on the seedling growth and the reduction of photoinhibition.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.15-19
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• 2001

This study was carried out to investigate the effect of application time and amount of rice bran on rice yield, weed occurrence, and chemical change in water as applied at the level of 1.8 Mg/ha (1.8RB) and 3.5 Mg/ha (3.5RB) through field and pot experiment. $Nitrate(NO_3\;^-)$ in the surface water and the percolated water through pot were high in application of 3.5RB, and similar in application of 1.8RB as compared to chemical fertilization. Electric conductivity in surface water were higher by application of rice bran until 25 days after rice bran application. $NH_4-N$ in soil were lower in application of rice bran, and $NO_3-N$ in soil were higher in 3.5RB at tillering stage and panicle formation stage of rice. Rice bran application(3.5RB) showed 68% of weed occurrence as compared to that of chemical fertilization. Rice yield were increased by heavy application of rice bran; 4.41 Mg/ha in 1.8RB and 4.87 Mg/ha in 3.5RB, and top dressing of nitrogen at panicle formation stage caused to increased rice yield by $14{\sim}15%$. Rice yield was also increased by early application of rice bran.

• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.145-149
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• 1998

To find out the effect of water hyacinth(Eichhornia crassipes Solms-Laub) on the control of eutrofication and plant damage with irrigation water contamination, its ability to remove the nutrients such as nitrogen and phosphrus was studied. The overall results are summarized as follow. 1. It was possible to cultivate water hyacinth for 4 month from June to the middle of October in Suwon. 2. The number of plant was increased from 1,320 to 50,600 for 4 months, and total amounts of N, P, K removed from Seo-Ho by water hyacinth were 78.3, 64.2 and 152.4 kg/10a, respectively. 3. EC and $NH_4-N$ contents were lower at water hyacinth treatment than non-treatment and monthly variation of those contents were decreased until August. 4. With the cultivation of water hyacinth in animal waste water in vinyl plastic house, pH, EC, COD and concentrations of $NH_4-N$ and $PO_4-P$ in the water were drastically decreased. 5. Nitrogen contents absorbed from waste water existed in the order of leaf > stem > root but those of phosphorus root > stem > leaf.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.26-33
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• 1998

This experiment was conducted to classify the plant species occurring in the saline reclaimed land by saline tolerance. The vegetation of reclaimed land was composed of various plant species from halophyte to glycophyte showing different saline tolerances. In the investigated saline region, reclaimed land of Youngjong island, Inchun city, 175 species belonging to 32 families were found. Our survey was carried out in two region, having different salinity due to different desalinization. The electricalconductivity (EC) of more saline region showed 48.0mS/cm nd the other region showed 13.0mS/cm. It is assumed that intensity of precipitation and runoff of rainfall may cause salinity gradient in the investigated region. The plant species occurred in the experimental region were classified as 72 species of annual, 42 species of biennial, and 61 species of perennial according to life cycle. For knowing relationship between vegetation of saline region and saline tolerance of occurring species, we tested the saline susceptibility of plant species collected at the saline regions. Testing plants were cultured by nutrient solution containing 200 mM NaCl, the critical concentration of survival in glycophytes. The saline tolerance was graded by the growing capacity in the sand-culture system. The more saline-tolerant species screened by sand culture were Atriplex gmelini, Suaeda asparagoides, Aster tripolium, Suaeda maritima, Salicornia herbacea, and Suaeda japonica. The most saline tolerant family was Chenopodiaceae. Poaceae, Cyperaceae, and Brassicaceae showed relatively high tolerance to saline stress. In the course of growth under the high saline condition, the most noticeable change was the darkening of leaves by increasing of chlorophyll content. The chlorophyll contents were increased with saline stress in most species.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.54-58
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• 1998

This experiment was conducted to find out the effects of fermented compost using cattle manure and Autoclaved Lightweight Concrete(ALC) waste and duck raising in rice growing paddy fields on growth and quality of rice. By application of fermented compost of cattle manure incoporated ALC waste with amount of 2,000kg/10a, rice yield was reduced 2.9%, and 4.1% in 1,000kg/10a of compost with raising ducks plots as compared with application of standard level of chemical fertilizer. The ratio of head rice was slightly high in plots of compost application and white-belly kemeled rice was reduced by application of $1,500{\sim}2000kg/10a$ compost. The ratio of Mg/K was the highest in application of 1,000kg compost with raising duck. Efficiency of weed control by raising duck with free hexbiades was sufficient and their effects showed no difference between raising duck plots and herbidde plot.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.65-69
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• 1998

In order to evaluate the utility of bituminous coal fly ash, gypsum, oyster shell as soil amendments, aadic clayloam paddy soils with low calaum content were amended in the upper 15㎝ with amendments, and then Chinese cabbage was cultivated under plastic film house. Amendments treated were, in metric tons per hectare, i) none(Check) ; ii) 80 fly ash(FA) ; iii) 4 shell(SH) ; iv) 56 fly ash+24 gypsum (FG) ; v) 40 fly ash+24 gypsum+0.8 shell(FGS). On the whole, soil chemical properties were improved by amendments treatments. Amongst treatments, FA prominently neutralized soil pH and increased contents of Av. $P_2O_5$, Ex. K, and Av. B in soils. Besides, it showed the highest ratio in bacteria/fungi and (bacteria+actinomycetes)/fungi. FGS also affected the neutralization of soil pH and the increment of Ex. Mg. Amendments plants appeared alkaline damages only at early growing stage, but showed positive responses in fresh weight yields : 23% for FGS : 21% for FG : 19 18% for SH. At harvesting, leaves both of FA and FGS plants had higher values in contents of N, P, K, Ca, Mg, Fe, Mn, Zn, B, reduang-sugar, and vitamin-C than of others. In especial, Check plants appeared the heart rot symptoms owing to calaum defiaency differently from amendments plants. Taken together, FGS was an effective combination enable to maximize the utility of fly ash, gypsum, shell as soil amendments, espeaally in cabbage yield and quality.