• Korean Journal of Soil Science and Fertilizer
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• v.37 no.6
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• pp.357-364
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• 2004

Modern agriculture depending on chemicals such as fertilizers and pesticides gave rise to questions about long-term sustainability of agriculture in relation to degradation of soil quality. Improving soil quality is prerequisite to sustain biological productivity, maintain environmental quality, and promote plant and animal health. Assessment and monitoring of the health and quality of soil is necessary to provide opportunity to evaluate and redesign soil management system for sustainability. To develop the soil quality assessment method, we collected national data on soil properties of paddy and upland and attempted to evaluate the data in aspect of soil quality by the process of selecting a minimum data set (MDS), scoring the soil properties and calculating soil quality index (SQI) integrating the score of each soil property. This approximation indicated that soil quality index was in the order of paddy soil, upland soil and plastic film house soil.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.20-28
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• 2009

The sustainability of conventional agriculture which is characterized by input dependent and ecologically simplified food production system is vague. Chemicals and present practices used in agriculture are not only costly but also have widespread implications on human and animal health, food quality and safety and environmental quality. Thus there is a need for alternative farming practices to sustain food production for the escalating population and conserve environment for future generations. The present research scenario in the area of plant microbe interactions for maintaining sustainable agriculture suggests that the level of internal regulation in agro-ecosystems is largely dependent on the level of plant and microbial diversity present in the soil. In agro-ecosystems, biodiversity performs a variety of ecological services beyond the production of food, including recycling of nutrients, regulation of microclimate and local hydrological processes, suppression of undesirable organisms and detoxification of noxious chemicals. Controlling the soil microflora to enhance the predominance of beneficial and effective microorganisms can help improve and maintain soil chemical and physical properties. The role of beneficial soil microorganisms in sustainable productivity has been well construed. Some plant bacteria referred to as plant growth-promoting rhizobacteria (PGPR) can contribute to improve plant growth, nutrient uptake and microbial diversity when inoculated to plants. Term PGPR was initially used to describe strains of naturally occurring non-symbiotic soil bacteria have the ability to colonize plant roots and stimulate plant growth PGPR activity has been reported in strains belonging to several other genera, such as Azotobacter, Azospirillum, Arthrobacter Bacillus, Burkhokderia, Methylobacterium, and Pseudomonas etc. PGPR stimulate plant growth directly either by synthesizing hormones such as indole acetic acid or by promoting nutrition, for example, by phosphate solubilization or more generally by accelerating mineralization processes. They can also stimulate growth indirectly, acting as biocontrol agents by protecting the plant against soil borne fungal pathogens or deleterious bacteria. Present review focuses on some recent developments to evolve strategies for better biotechnological exploitation of PGPR's.

• Journal of Soil and Groundwater Environment
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• v.27 no.5
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• pp.10-17
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• 2022

Inorganic acids such as HCl, HNO₃, and H₂SO₄ have been commonly applied to soil washing of heavy metals-contaminated soil due to their cost-effectiveness. However, implementing the 'Chemical Substance Control Act' requires off-site risk assessment of the chemicals used in the soil washing. Therefore, in this study, organic acids or Fe(III)-based washing agents were evaluated to replace commonly used inorganic acids. Ferric removed heavy metals via H⁺ generated by hydrolysis, which is similar to the HCl used in the control group. Oxalic acid and citric acid were effective to remove Cu, Zn, and Cd from soil. Organic acids could not remove Pb because they could form Pb-organic acid complexes with low solubility. Furthermore, Pb could be adsorbed onto the iron-organic acid complex on the soil surface. Ferric could remove exchangeable-carbonate, Fe-Mn hydroxide, and organic matter and sulfides bound heavy metals (F1, F2, and F3). Organic acids could remove the exchangeable-carbonate and Fe-Mn hydroxide bound metals (F1&F2). Therefore, this research shows that the fractionation of heavy metals in the soil and the properties of washing agents should be considered in the selection of agents in the process design.

• Journal of Embryo Transfer
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• v.26 no.4
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• pp.297-304
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• 2011

Polybrominated diphenyl ethers (PBDEs) are a class of "brominated" (bromine containing) man-made chemicals used as flame retardant additives in plastics, foams, and textiles. PBDEs are found in various environmental contaminants in air, soil, sediment, and water, and 209 individual forms (congeners) of PBDE exist. Among these, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is the dominant congener found in the environment. Exposure to BDE-47 is now worldwide, and levels of BDE-47 have been detected in the blood of animals, including humans. BDE-47 can adversely affect the developmental system in both humans and animals. BDEs have structural similarities to polychlorinated biphenyls and thyroid hormones. However, recent studies have shown that BDEs may act as hormonal disrupting chemicals with detrimental effects. Therefore, a reliable assessment of BDE-47 toxicological action is required to understand the detrimental impacts of BDE-47 on human health. In this review, we overview recent studies on the distribution and potential toxicological effects of BDE-47 in humans and animals.

• Journal of Food Hygiene and Safety
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• v.23 no.1
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• pp.26-30
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• 2008

Polycyclic Aromatic Hydrocarbons(PAHs) contamination arises from several source including processing of food(smoking, direct drying, cooking) and environmental contamination of air, water or soil. A red ginseng is produced by steaming the root followed by drying. The methodology involved extraction with n-hexane and washing with water, clean-up on Sep-Pak Florisil Cartridges and determination by HPLC/FLD. The mobile phase was a mixture of acetonitrile and water in 8:2 by the isocratic elution and the excitation wavelength of fluorescence detector was 294 nm and its emission wavelength was 404 nm. The average recovery was about 105% and the relative standard deviation was 0.5. The levels of benzopyrene in the selected red ginseng beverage samples were not detected.

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.1-7
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• 1997

We investigated the influence of various known sterilization methods on atrazine assimilation. The present study was designed to investigate the effect of autoclaving, sodium azide and mercuric chloride treatment on the assimilation of atrazine in soil and sediment. The sterilization reactor treated with sodium azide resulted in $^{14}CO_2$ generation and atrazine was rapidly disappeared from reactor through chemical reaction with sodium azide. These findings seem to indicate that sodium azide sterilization is not recommended for atrazine studies. In sample reactors autoclaved or treated with mercuric chloride, $^{14}CO_2$ generation was not detected and most of the disappeared atrazine was found to exist as hydroxyatrazine. These results suggested that autoclaving or mercuric chloride treatment could be effective sterilization methods. However, chemical properties(pH and redox potential) of soil and sediment were altered by any of the sterilization methods applied. So it was suspected that these altered properties could affect distribution and mineralization of atrazine in soil and sediment. In addition, both autoclaving and mercuric chloride treatment have altered $K_d$ values of hydroxyatrazine more significantly than those of atrazine. Consequently, although autoclaving and mercuric chloride treatment are effective sterilization methods, one must be careful in using them in practice as these methods may cause chemical degradation of both of atrazine and its metabolites and changes in chemical properties of soil and sediment. In conclusion, careful assessment of sterilization methods must be made for the degradation studies of chemicals in soil and sediment in order to minimize possible undesirable chemical degradation of sample and/or changes in physico-chemical properties of soil and sediment by the selected sterilization methods.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1098-1108
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• 2008

Batch type and column type experiments were performed in order to predict adsorption and movement within soil. Clay minerals montmorillonite and kaolinite were respectively added to paraquat which is a cationic compound with long residual time, 2,4-D which is an anionic compound with relatively short residual time and napropamide which is an amphoteric compound. Therefore, it is very important to determine the movements of toxic pollutants in the ground soil to establish measures to prevent soil grounds contamination and to restore contaminated soils effectively, because contamination of soil is getting severe due to these toxic wastes, industrial waste water, and agricultural chemicals, etc. Therefore, in this study, we have carried out column and batch experiments by using general toxic organic compounds as test samples in order to restore contaminated soils effectively as well as to prepare a basic data to develop absorbents that will remove various toxic organic compounds, with a grandiose purpose to prevent contaminations of soil and grounds due to various toxic organic compounds.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.153-161
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• 1999

No-till direct-sown rice-wheat relaying cropping system has major advantages such as labor and cost saving by eliminating tillage and preparation of seed bed and transplanting. In this system, rice sowing was done simultaneously wheat harvesting. A paddy field experiment was conducted to evaluate effects of no-till years on soil microbial changes and soil physico-chemical characteristics with rice growth and development. Chemical fertilizers and agricultrual chemicals was not applied in no-till system. As the year in no-till direct-sown system the air permeability was increased and after water submerging soluble nitrogen was released Aerobic microbial-n was highest in May and then decreased after water irrigation. The population of aerobic soil microorganisms were steeply decreased after water submerging Soil microorganisms was decreased with the increased the soil depth. A month was needed for the seedling establishment in a no-tillage rice-wheat cropping system. Increased cropping years improved leaf greenness and leaf area index(LAI). But stomatal conductance(Gc) was higher in conventional cultivation system than no-till system. Stomatal conductance at panicle initiation stage was increased higher in conventional condition of leaves but the difference between conventional and no-till system was increased at heading stage. In no-till 4 years condition rice grain yield was spikelet numbers per panicle.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.43-46
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• 2004

Explosive chemicals have been major soil and groundwater contaminants especially in the nations with active military activities. Of these explosives, 2,4,6-trinitrotoluene (TNT) is the most refractory one due to its structural characteristics. Although its efficient reduction by Fe(0) is well-known, the reduction products - mainly aminotoluenes - still possess toxicities to terrestrial biota, and are resistant to biological degradation. In this study, therefore, abiotic transformation of TNT reduction products via oxidative-coupling reaction was evaluated using Mn oxide which is ubiquitous in natural soils. The transformation efficiency is increased with the number of amino groups. Considering the very efficient reduction rate of TNT by Fe(0), Mn oxide can be successfully used for the removal of TNT reduction products.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.489-492
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• 2003

This study is objected to identify the annual variation of shallow groundwater quality in the study area, Hwabong-Jangam, Iljuk-Meon, Kyunggi-Do. The previous study in 2002 shown a wide-spread contamination of shallow groundwater by nitrate mainly originated from wastes of livestock facilities. In the year 2003, groundwater quality of the area has worsened due to the agricultural activities including the application of organic fertilizer and agro-chemicals to improve soil quality. In addition, a leaking septic tank, identified in the previous study, is still expanding its influence on the nearby wells.