• 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.

• Korean Journal of Organic Agriculture
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• v.19 no.1
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• pp.121-134
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• 2011

For this study, Smilex powder, a pesticide, was sprayed on the Altari radish, and then underground water, Chitosan solution (${\times}$500), and wood vinegar solution (${\times}$1000) were evenly sprayed on the Altari radish respectively. Samples of Altari radishs for residual pesticide analysis were taken two hours, 1 day, 7 days, and 15 days after treatments, and the detectable concentration and degradability of procymidone, the pesticide residue, were measured. The results obtained are as follows: 1. When detectable concentration of procymidone within the altari radish was measured, treatment plots sprayed with underground water, Chitosan solution (${\times}$500), and wood vinegar solution (${\times}$1000) were found to show lower detectable concentration than the non-treatment plot which was sprayed with pesticide only. Especially, the treatment plots sprayed with Chitosan solution (${\times}$500), and with wood vinegar solution (${\times}$1,000) showed lower values than the average. 2. When the degradability of procymidone within the Altari radish was measured, the plot treated with Chitosan solution (${\times}$500) and the plot treated with wood vinegar solution (${\times}$1,000) were found to have relatively higher degradability of procymidone. There were not much differences among testing materials in the degradability of residual pesticides. However, the plot treated with Chitosan solution (${\times}$500) showed higher degradability. In terms of average degradability with time, degradability increased sharply 7 days after the foliar application of testing materials. 3. When the daily far-sighted view survey was conducted in order to find out growth disorder and damage on the Altari radish plants by the treatment of un-derground water, Chitosan solution (${\times}$500), and wood vinegar solution (${\times}$1,000), no symptomatic physiological disorders was observed on all the plants tested during the whole growing season at the tested concentration level.

• Analytical Science and Technology
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• v.13 no.6
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• pp.722-730
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• 2000

The residual concentration and half-life time of synthetic pyrethroid insecticide cyfluthrin in potato and soil were investigated by gas chromatography (GC). The pesticide in potato was extracted with n-hexane, filtered and concentrated. The concentrated phase was transferred to the Sep-Pak silica gel column and purified with acetonitrile and acetone for the analysis by gas chromatography equipped with electron capture detector (GC-ECD). From the standard additional experiments with 0.01 and $0.1{\mu}g$, the recoveries were 85-87% and the detection limit was 0.005 ng. The soil sample was extracted with acetone and dichloromethane. The organic phase was concentrated and redissolved with n-hexane and analyzed with GC-ECD after cleaned with Sep-Pak column. From the standard additional experiments with 0.01 and 0.1 ng, the recoveries were 84-88% and the detection limit was 0.005ng. The half-life time of cyfluthrin in the silty clay was 25 days in the room laboratory and 0.6 days in the fieJd test whereas it was 38 days and 0.5 days for each in case of silty loam.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.136-145
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• 2020

This study was conducted to evaluate pesticide residues and foreign metallic matter on a total of 104 powdered agricultural products in Incheon. Residue testing for 373 pesticides was conducted by GC-MS/MS, LC-MS/MS, GC-ECD, GC-NPD and HPLC-UVD. Foreign metallic matter was detected by magnetic rod. As a result pesticide testing, 7 of the 104 products were found to be within the MRL of the pesticides. The detected pesticides were chlorpyrifos, etofenprox, fenoxanil, malathion, permethrin, tebuconazole and tetraconazole. As for foreign metallic matter, 16 samples were above the allowable limits set by Korean regulations. Therefore, the inspection of residual pesticides in raw material, and the removal of foreign metallic matter will require further stringent attention for the safety of powdered agricultural products.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.484-497
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• 2024

Neonicotinoid pesticides, widely used worldwide as potent insecticides, have been found to have detrimental effects on the environment and living organisms due to their persistent residues. This study aimed to investigate the neonicotinoid pesticides, imidacloprid, and clothianidin, focusing on their impact on honey bee toxicity and foliar residue levels. Alfalfa was selected as control crop while bell peppers, and cucumbers were chosen as representative application crops, respectively. The investigation involved comparing the toxicity and foliar residue levels resulting from soil and foliar treatments, with a focus on identifying potential shortcomings in conventional foliar residue toxicity testing methods. Imidacloprid and clothianidin were applied to crops or soil at recommended rates and through irrigation. The honey bee mortality rate (RT₂₅) over time was determined, and pesticide residues on leaves were quantified using High-Performance Liquid Chromatography (HPLC). The results revealed that foliar treatment with imidacloprid on alfalfa resulted in an RT₂₅ of less than 1 day, with residues ranging from 1.07 to 19.27 mg/kg. In contrast, application on bell peppers showed RT₂₅ within 9 days, with residues ranging from 1.00 to 45.10 mg/kg. Clothianidin foliar treatment displayed RT₂₅ within 10 days on alfalfa, with residues between 0.61 and 2.57 mg/kg. On bell peppers, RT₂₅ was within 28 days, with residues ranging from 0.13 to 2.85 mg/kg. Soil treatment with imidacloprid and clothianidin in alfalfa exhibited minimal impact on honey bees and residues of 0.05 to 0.37 mg/kg. However, in applied crops, imidacloprid showed RT₂₅ within 28 days and residues ranging from 4.47 to 130.43 mg/kg, while clothianidin exhibited RT₂₅ within 35 days and residues between 5.96 and 42.32 mg/kg. In conclusion, when comparing honey bee toxicity and foliar residues among crops, application crops had a more significant impact on honey bee mortality and higher residue levels compared to control crops. Moreover, soil treatment for application crops resulted in higher RT₂₅ and residue levels compared to foliar treatment. Therefore, to ensure pesticide safety and environmental sustainability, diverse research approaches considering different crops and application methods are necessary for the safety assessment of imidacloprid and clothianidin.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.239-249
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• 2024

In this study, we investigated the concentrations of pesticide residues in agricultural products marketed in northern Seoul and assessed their potential health risks. A total of 1,737 samples were collected using the QuEChERS method, followed by LC-MS/MS and GC-MS/MS. Pesticide residues below the MRLs were detected in 560 samples of 72 items (32.2%), but 38 samples of 22 items had pesticide residues above the MRLs. Residual pesticides were detected in 53.8% of fruits, 33.0% of vegetables, 28.6% of herbs, 15.4% of beans, and 10.5% of rice samples. Most of the samples that exceeded the MRLs were vegetables, especially leafy, stalk, stem, and root vegetables; herbs and mushrooms also exceeded the permitted MRLs. Of the 105 pesticides investigated, dinotefuran, fluxametamide, chlorfenapyr, azoxystrobin, and carbendazim were the most frequently detected, whereas 23 pesticide residues, including terbufos, carbendazim, and fluxametamide, were detected above the MRL values. The hazard indices were calculated as 0.00003-1.31406%, which suggests that the investigated pesticide residues in the samples were within safe levels, but continuous monitoring of pesticides in agricultural products is needed to ensure the safety of consumers.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.125-132
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• 2001

The present study was conducted to investigate biological degradability of phosphamidon and profenfos. In the biodegradation test of two pesticides by the modified river die-away method from May 20 to July 29, 1999, the biodegradation rate was determined in Nakdong (A) and Kumho(B) River. The residual percentages of phosphamidon were 74.9%, 68.8% and 62.7% in control, A and B samples 7 days after applicaton, respectively. Biodegradation constants and half-lives of phosphamidon were 25.1%, 21.9% and 11.9% in control, A and B samples 7 days after application. Biodegradation constants and half-lives of profenofos were 0.0005 and 58.4 days in A, 0.0013 and 21.6 days in B, respectively. The biodegradation rates of phosphamidon and profenofos were higher in the Kumho River (B) than in the Nackdong River(A). The strains of microorganisms for the degradation of phosphamidon and profenofos were identified as Klebsiella pneumoniae, Aeromonas hydrophila and Acinetobacter calcoaceticus, all Gram-negative bacteria. In order to identify biodegradate products, the extracts of cultivates were analyzed by GC/MS. The mass spectra of biodegradate roducts of phosphamidon were at m/z 153 and 149, those of the profenofos were at m/z 208 and 240, respectively. It was suggested that the biodegradate metabolites of phosphamidon were O, O-dimethyl phosphate(DMP) and N, N-diethylchloroacetamide, those of profenofos were 4-bromo-2-chlorophenol and O-ethyl-S-propyl phosphate.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.312-318
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• 1995

Residues of benfuresate in rice and oxolinic acid in Chinese cabbage were determined through the field experiments in order to establish the safe use and the maximum residue limit(MRL) of these pesticides in Korea. The herbicide benfuresate powder was sprayed into the paddy field with a level of 0.6kg(active ingredient)/ha and rice (Oryza sativa L.) was grown. At harvest, residues of benfuresate in brown rice and stem were analyzed using gas chromatograph. The residue of oxolinic acid in Chinese cabbage (Brassica campestris subsp. napus var pekinesis MAKINO) was analyzed using HPLC after foliar-spraying this fungicide into the cabbages at a level of 15kg/ha. The recovery efficiencies of benfuresate and oxolinic acid were 87-89% and 90-95%, respectively. The respective residues of benfuresate in rice and oxolinic acid in Chinese cabbage were in the range of 0.27-0.46 mg/kg and 0.23-1.53kg/kg. Residual concentrations of these pesticides in crops increased with the increased application frequencies, followed the first-order kinetics and linearly decreased with time. The highest residue of 1.53 mg/kg of oxolinic acid was observed when this fungicide was sprayed six times until three days prior to harvest, but this level was far lower t㏊n 5 mg/kg, which is the maximum residue limit(MRL) set by FAO/WHO.

• Korean Journal of Agricultural Science
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• v.32 no.2
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• pp.215-221
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• 2005

The residual study of pesticide has been used in various areas, such as food safety, environmental protection, establishment of tolerance, and explaining the pathway and reaction mode of pesticides, and its importance was expected to increase further more. The aspect of food safety, the pesticide residue survey have been practiced at many organizations, but there were no verification of analytical results at present. In this experiment, we focused on instrumental stability, including response of each instrument and the recovery ratio of each organization's method. As samples for this experiment, we prepared cucumber and sesame, and chose 4 pesticides (bifenthrin, chlorpyrifos, diazinon, and ethoprophos), which were mostly detected from pesticide residue survey and widely used for each crop. The standard deviation of peak areas in the chromatogram of each pesticide were under 1.212 %, so it showed that most instruments were stable. The relationship of recovery ratio of each organization were over 0.996 for every pesticide and each organization. Finally, the analytical results for pesticide residue from each participated organization were not statically significant and we could put confidence in the result from each organization.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.281-288
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• 2009

The strobilurin fungicides, azoxystrobin and kresoxim-methyl, were investigated to know the biological half-lives and dissipation patterns in Korean melon under plastic film house condition. Used pesticides for field application were 20% azoxystrobin of suspension concentrate and 47% kresoxim-methyl of water dispersible granule. Two pesticides were sprayed at recommended and double dose rate. Pesticide residues in Korean melon were analyzed until 14 days after application. The azoxystrobin was analyzed by HPLC equipped with UV detector after cleanup with florisil glass column. Initial residue concentrations of azoxystrobin in Korean melon at recommended and double dose rate were 0.09 mg/kg and 0.14 mg/kg, respectively. Those were less than 0.2 mg/kg maximum residue limit of Korean melon established by KFDA. The biological half-lives of azoxystrobin in Korean melon were 4.7 days at recommended dose rate and 7.8 days at double dose rate. Initial concentrations of kresoxim-methyl which was analyzed by GLC-ECD in Korean melon at recommended and double dose rate were 0.10 mg/kg and 0.23 mg/kg, respectively. Those were less than 1.0 mg/kg, MRL. The biological half-lives of kresoxim-methyl in Korean melon were 4.1 days at recommended dose rate and 4.8 days at double dose rate. The residue amounts of both pesticide was lower than MRL and biological half-lives were not so long. Because the weight of Korean melon under plastic film house condition was fast increased during cultivation.