• Korean Journal of Environmental Agriculture
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• v.3 no.1
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• pp.22-29
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• 1984

The Freundlich-type adsorption isotherms were obtained in this study on the adsorption of linuron, bentazon, trifluralin and butachlor by soils. A strong correlation was shown between soil organic matter content and the adsorption of linuron. Soils with high organic matter content adsorbed more linuron. There was no significant correlation between the adsorption of bentazon and clay content. There was a tendency that increase in organic matter content acts against the adsorption of bentazon. Repulsive forces seemed to exist between negatively charged soil particle surfaces and betazon molecules which become weakly charged negative ions in soil solution. Organic matter content and cation exchange capacity appeared to be enhancing the adsorption of trifluralin and butachlor. Clay content was not significantly correlated with the adsorption of these herbicides. Trifluralin was adsorptive to the greatest extent, followed by linuron and butachlor, bentazon being the least.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.335-345
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• 2005

A study on changes on the distribution of vascular hydrophytes and the growth pattern of Schenoplectus triqueter (Scirpus triqueter) was undertaken at the Nakdong River estuary from 2002 to 2004. The change was due to physical alteration of the estuary for the past 25 years. These plant species are the major food sources for winter waterfowl. A total of 32 species of vascular hydrophytes from 17 families were found in the West Nakdong River (freshwater), the main channel of Nakdong River (freshwater) and the Nakdong River Estuary (brackish water). After the construction of the barrage on the estuary in 1987, the number of hydrophytes has remarkably increased to 17 species (5 species in 1985) in the main channel of the River. In particular, a community of Eurale ferox was found at the backwater wetland of the Daejeo side of the main channel. The introduced species of Eichhornia crassipes and Pistia stratiotes that were epidemic in 2001 at West Nakdong River was not found any more. The other species such as Nymphoides indica, Myriophyllum spicatum, Ruppia spp. were rediscovered. The large area (about 1,300ha) of Zostera spp. was the main sources of food for swans, but disappeared because of direct and indirect impacts of reclamation in the River estuary. Currently, there remains a small patch of Zostera spp. and about 250ha of S. triqueter. Schenoplectus triqueter grew mostly between April-September and tuber formed, between September-October. The growth of S. triqueter up to $60\sim80cm$ in length was observed in 5 sites out of the 7 sites in brackish area. Tubers of S. triqueter were eaten by waterfowls such as swans as winter food. In five sites, tubers took $44\sim57%$ of total biomass in October. Tubers were found in deep layers; $5\sim15cm$ (9%), $15\sim25cm$ (28%), $25\sim40cm$ (55%), below 40cm $(6\sim7%)$. The distribution of vascular hydrophytes has remarkably changed in the Nakdong River Estuary due to the reclamation of the area. In order to determine the extent of changes of the distribution of these plants and the carrying capacity of the area for waterfowl, an intensive research is urgently needed.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.441-452
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• 2011

This study was carried out to survey the residual characteristics of endocrine disruptor (ED)-suspected pesticides in greenhouse soils and assess their leachabilites to groundwater. Greenhouse soils were collected from 40 sites of greenhouse in 2008 in Korea. Sixteen ED-suspected pesticides which had been using in Korea, such as alachlor, benomyl, carbaryl, cypermethrin, 2,4-D, dicofol, endosulfan, fenvalerate, malathion, mancozeb, metribuzin, metiram, methomyl, parathion, trifluralin, and vinclozolin, in the soils, were analyzed by chromatographic methods using GLC-ECD and HPLC-DAD/FLD. Limits of detection (LODs) of the test pesticides ranged from 0.0004 to 0.005 mg/kg. Recoveries of the target pesticides from soil ranged from 72.69 to 115.28%. Four pesticides including cypermethrin were detected in the range of from 0.001 to 2.019 mg/kg, representing that their detection rate from greenhouse soils was 37.5%. The highest detection rate was observed from endosulfan which was detected from 16 site soils of the total samples, indicating that endosulfan is persistent in soil because of its very low mobility and high adsorption characteristics in soil. Based on the groundwater ubiquity scores (GUSs) of the pesticides detected from greenhouse soils, most of them have little possibilities of groundwater contamination except the fungicide vinclozolin with some leaching potential because of high water solubility and very low soil adsorption property.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.70-78
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• 1998

Dissipation, adsorption and desorption of oxadiazon were examined in two soils containing different amounts of soil organic matter. In addition, reactivity of oxadiazon with humic monomers was searched to clarify binding mechanism of oxadiazon to soil organic matter in the presence of a laccase of Myceliophthera thermophila. Half lives of oxadiazon were 38 days in Soil I and 45 days in Soil II. Freundlich constant, k values of fresh soils were higher than those of oxidized soils. Adsorption rates of oxadiazon were increased 17.1% in Soil I and 9.3% in Soil II in the presence of a laccase but no significant increase was observed in oxidized soils. Desorption rates of oxadiazon in fresh soils were lower than those in oxidized soils. Desorption rates of adsorbed oxadiazon in soils addes with the enzyme were not changed in oxidized soils but decreased in fresh soils. The herbicide oxadiazon alone underwent no transformation by a laccase but in the presence of catechol, guaiacol and gallic acid as humic monomer, transformation rates of it were from 20% to 24%.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.36-44
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• 1998

To develope cost-effective new granular formulation of mixture with 7.0% chlomethoxyfen and 3.5% butachlor, this study was conducted by investigation of floatability, dispersibility or collapsability and released concentration of active ingredients in water and bio-efficacies of the granules formulated by different formulation methods compared to commercial pellet-extruded granules. They were formulated by coating on or impregnation into extruded pellets, sands and zeolites with two active ingredients, binders, friction reducer, dispersing agents and bentonite. Pellet-coated method showed similar floatability, collapsability and bio-efficacy to the commercial pellet-extruded one or better than that but unstable patterns of released concentration of chlomethoxyfen because of easy isolation of coated technical particles from the surface of granules. Sand-coated methods showed similar physical properties, released pattern of two active ingredients, and bio-efficacy to the commercial one. Liquid binders and/or dispersing agents are more important than powdered ones to control released concentration of active ingredients from the granule mixtures, to improve the floatability and dispersibility, and to show good bio-efficacy. Sand-coated one might be a suitable method if types and amount of liquid binders and dispersing agents are selected.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.219-225
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• 2010

The solubility in water of granular pesticides is not equal because the difference of methods of producing a granular pesticide. This study was conducted to investigate fish acute toxicity of butachlor 5% GR, fipronil 0.4% GR by impregnation and carbosulfan 3% GR, diazinon 0.4% GR by coating, using carp (C. carpio), medaka (O. tatipes) and loach (M. anguillicaudatus). The test solution of each pesticide was prepared by direct addition of granular pesticide and add after grinding granular pesticide to powder in test water, We also investigated $LC_{50}$ and residual concentration until 96 hours. Test results were appeared that the treatment of powder was 1.2~4 time higher than granular and toxicity increased clearly according to elapsed time, And the residual amounts by time were detected much at early time in the powder treatment of butachlor GR and diazinon GR. Conclusively, fish acute toxicity and residual concentration in test solution appeared higher in the powder treatment than treat granular form directly in water. Also, 96 hours toxicity values were stable comparatively and the error is less than 48 hours.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.230-240
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• 2015

An IOM sampler equipped with glass fiber filter has been recently utilized instead of solid adsorbent, which was used to measure the inhalation exposure of agricultural operator to pesticides. The aim of this study is to validate the efficacy of an IOM sampler by measuring the trapping efficiency and breakthrough using kresoxim-methyl water-dispersible granule and fenthion emulsifiable concentrate. On LC-MS/ MS, minimum detection level was 12.5 pg and method limit of detection was 5.0 ng/mL. Good linearity ($R^2$ > 0.999) for matrix matched standards was obtained. Recoveries of pesticides from glass fiber filter were 102-109% (kresoxim-methyl) and 97-104% (fenthion) while those from XAD-2 resin were 94-98% (kresoxim methyl) and 93-100% (fenthion). Trapping efficiency test was performed with personal air pumps and IOM sampler (glass fiber filter) connected with solid adsorbent (XAD-2 resin) with two types of formulation (solid and liquid) which were diluted by standard rate and sprayed to IOM sampler. Those pesticides were trapped only in glass fiber filter without any breakthrough to solid adsorbent. After spiking of pesticides to glass fiber filter, breakthrough test was carried out with IOM sampler (glass fiber filter) which was connected with solid adsorbent. As a results, 87-101% of kresoxim-methyl and 96-105% of fenthion remained in spiked glass fiber filter, however, no pesticides were detected in second glass fiber filter and solid adsorbent. In conclusion, IOM sampler which equipped with glass fiber filter can be applied widely for pesticide inhalation exposure study since it has good trapping efficiency and adsorption capacity, regardless of the solid or liquid formulation.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.04a
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• pp.50-51
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• 1993

광학활성 물질의 분할은 화학공정에 있어서나 생명과학에 있어서 중요한 분야로, 특히 의약이나 농약등의 생리활성물질에 광학이성질체가 상당수 존재하고 있으며, 그중에서는 경상체간에 생리활성이 현저하게 다른 것이 상당수 존재한다. 이러한 광학활성 물질을 분리하는 방법으로는 크로마트그래피를 이용한 방법, Diastereomer를 이용하는 방법등이 있으나 본 연구에서는 고분자 착체막을 이용하여 경상체를 분리하고자 한다. 전이금속착체를 이용한 경상체의 분리는 주로 crown ether를 중심으로 이루어져 왔다. 즉 전이금속의 흡착력과 crown ether의 입체구조를 이용한 것이다. 그러나 이것은 액막에서나 가능한 것으로 고체막에서는 사용할 수 없다. 따라서 본연구에서는 아크릴 계통의 고분자 전이금속 착체막을 이용하여 아미노산 경상체간의 분리를 행하고자 한다. 즉 전이금속의 흡착력과 리간드의 입체구조를 이용하여 경상체를 분리하는 것이다.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.236-246
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• 2014

Pesticide is used to protect the crops, but also become a cause of polluting the environment. Perform a risk assessment using physical and chemical properties, environmental fate and toxicity data in order to determine the pesticide registration. The aquatic model estimates pesticide concentrations in water bodies that result from pesticide applications to rice paddies and apple orchard. The used models are the PRZM, EXAMS and AGRO shell (PA5), Rice Water Quality Model (RICEWQ) and Screening Concentration In GROund Water (SCI-GROW). The residual concentration of water body was estimated using meteorological data, crop calendar and soil series of Korea. The chosen pesticides were butachlor, carbofuran, iprobenfos and tebuconazole. It has shown the potential that the RICEWQ is possible to predict residue level in water of butachlor and iprobenfos, because the maximum value in water monitoring data is lower than the peak concentration of the model, and the minimum value is lower than the average annual concentration of the model. But RICEWQ was insufficient to predict exposure concentrations in ground water. The estimated exposure concentrations of carbofuran in ground water is very higher than in surface water because of its low soil adsorption coefficient. Although tebuconazole were not detected in the water monitoring that means very low concentration, it is possible that the PA5 can be used to predict residue level in water.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.144-153
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• 2007

One of the most recent issues facing the pesticides regulatory process is the assessment of the potential for pesticides to leach through soil and appear in groundwater. Since Jeju island depends on a hydrogeologically vulnerable aquifer system as its principle source of drinking water, it is important to identify which pesticides are the most likely to result in groundwater contamination. The objective of this study was to assess groundwater contamination risk of 21 pesticides (12 insecticides, 6 herbicides and 3 fungicides) in Jeju soils using groundwater ubiquity score (GUS). Considering GUS estimated in 21 representative series of Jeju soils, generally herbicides showed relatively higher leaching potentials and insecticides showed lower leaching potentials. Groundwater contamination risk was higher in the order of bromacil > metolachlor > alachlor > linuron pretilachlor > butachlor for herbicides, carbofuran > ethoprophos > diazinone > dimethoate > penthoate > mecarbam > methidathion > endosulfan > fenitrothion > parathion > chlorpyrifos > terbufos for insecticides, and metalaxyl > chlorothalonil > triadimefon for fungicides. Among the tested pesticides alachlor, metolachlor, bromacil, ethoprophos and carbofuran were classified as the pesticides of very high or high groundwater contamination potential. Although the ranking of the leaching potential was essentially determined on the base of the intrinsic properties of the chemicals and environmental properties, variation of the relative groundwater contamination potentials of each pesticides in different soils were not significant. Therefore, the above ranking of groundwater contamination risk would be applied in most of Jeju soils. To lower the possibility of pesticide contamination of groundwater, the use of those pesticides classified as high or very high leaching potential should be strictly regulated in Jeju Island.