• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.302-311
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• 1995

Benfuresate or oxolinic acid, as an experimental pesticide, was applied to the different textural paddy or upland soil respectively under the field condition and the residual concentrations were determined. Six kinetic models were employed to characterize the best-fit kinetic model describing the residual pattern of benfuresate or oxolinic acid and the $t\frac{1}{2}$ estimated from each model was comparatively assessed. All of the six models explained significantly the residual patterns of the pesticides but the empirical models such as PF, EL, and PB were not recommendable for the $t\frac{1}{2}$ estimation. Among theoretical models, the residual patterns were followed in the orders of the second-order(SO)>first-order(FO)>zero-order(ZO) kinetics, judging from the size and significance of coefficient of determination and standard error. However, the multiple FO model, consisting of the fast and slow decomposition steps, was better than the single FO model for the residual pattern and the $r^2$ in this case became similar to that of SO kinetic model. Thus the multiple FO and SO models were represented as the best fit model of the experimental pesticide. The $t\frac{1}{2}$ of benfuresate estimated from the single FO kinetic model in Weolgog and Cheongwon series was 49 and 63 days, respectively, which were 20 and 13% longer than the respective $t\frac{1}{2}$ from the SO kinetic model. The $t\frac{1}{2}$ of oxolinic acid from the FO model in Yonggye and Ihyeon series were 87 and 51% longer than those from the SO kinetic model, respectively. These results demonstrated that the best-fit model representing the residual pattern of a pesticide and the resultant $t\frac{1}{2}$ might be variable with the kinds of pesticides and the environmental conditions. Therefore it is recommended that the half-life of a pesticide be assessed from the best-fit model rather than from the FO kinetic model uniformly.

• Biomedical Science Letters
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• v.22 no.4
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• pp.140-149
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• 2016

All pesticides must be assessed strictly whether safe or not when agricultural operators are exposed to the pesticides in farmland. A pesticide is commonly regarded as safe when estimated dermal absorption amount is lower than the acceptable operator's exposure level (AOEL). In this study, dermal absorption rate of chlorpyrifos, a widely used organophosphate insecticide, was investigated using rat dermal tissue model. Chlorpyrifos wettable powder solved in water (250, 500 and 2,500 ppm) was applied to freshly excised rat dermal slices ($341{\sim}413{\mu}m$ thickness) on static Franz diffusion cells at $32^{\circ}C$ for 6 hours. After exposure period of 6 hours, and then washing-at residual amount of chlorpyrifos was analyzed in dermal tissues, tape strips, washing solution, washing swabs of receptor bottles and receptor fluids at 1, 2, 4, 8 and 24 hours. Chlorpyrifos was only detected in dermal tissue but not found in receptor fluid at each concentration and time point, and the absorption rate of 250, 500 and 2,500 ppm was 2.36%, 1.96% and 1.69%, respectively. The estimated exposure level of chlorpyrifos was calculated as 0.012 mg/kg bw/day. The health risk for farmers in this condition is a level of concern because the estimated exposure level is 12 times higher than AOEL 0.001 mg/kg bw/day. However, actual health risk will be alleviated than estimated because absorbed chlorpyrifos is not permeated into internal body system and only retained in skin layer.

• Food Engineering Progress
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• v.15 no.1
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• pp.28-33
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• 2011

UV-C and -B types of lamps, and $H_2O_2$ as a photocatalytic material were applied to optimize processing conditions for pesticides removal in Mandarine orange peel. Factors to affect the removal of pestrcides were arranged as a function of irradiation temperature, irradiation time, and $H_2O_2$ spray concentration. The optimum processing conditions for the chloropyrifos and the EPN removals in Mandarine orange peel were irradiation time of 60 min, irradiation temperature of $45^{\circ}C$ and $H_2O_2$ spray concentration of 1000 ppm. However, the optimum processing conditions for methidathion removal were 60 min of irradiation time, $40^{\circ}C$ of irradiation temperature and 1000 ppm of $H_2O_2$ spray concentration. The residual percentages of chloropyrifos, EPN and methidathion were 46, 49 and 28% after above irradiation processing, respectively.

• Korean Journal of Organic Agriculture
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• v.29 no.2
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• pp.257-273
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• 2021

Koreans consume cham-chwi (Aster scaber thunb.) as a common vegetable in a meal because of its bitter taste and rich flavor. In addition, it is the crop with the most residual pesticides detected in the last five years. Among the detected pesticides, the most common was azoxystrobin, which is a drug used primarily to prevent the leaf spot disease of A. scaber caused by Septoria sp.. We isolated the microorganisms that antifungal activity against Septoria sp.. The optimum incubation conditions (temperature, pH and growth medium) were examined for the growth of the isolates. Additionally, cellulase and protease activity and siderophore production ability were also examined. According to 16S rRNA sequencing of the isolate was affiliated to Paenibacillus polymyxa JE201. Largest inhibition zone measuring up to 9.2 mm was observed for P. polymyxa JE201 after 7 days of inoculation. P. polymyxa JE201 strain showed antifungal activity against various fungal phytopathogens Altanaria sp., Botrytis cinerea, Colletotrichum acutatum, Fusarium oxysporum, Phytophthora capsici, Ph. drechesleria, Rhizoctonia solani and Stemphylium sp.. Based on these observations, P. polymyxa. JE201 can be used as a promising biocontrol agent for preventing the leaf spot disease and other phytopathogens.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.281-290
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• 2019

BACKGROUND: As the demand for strawberries increases, people are paying attention to food safety in strawberry, especially pesticide residues. To remove the pesticides from strawberry, various washing and processing technique in households are additionally required. METHODS AND RESULTS: Strawberries were washed with water, detergent, alcohol, and ultrasonication and processed to strawberry jam. The mean reduction efficiency according to the washing solvent and method was found to be higher in the order of detergent (42.5%) > alcohol (41.7%) > water (41.3%) > ultrasoniation with alcohol (40.2%) > ultrasoniation with water (38.6%) > ultrasoniation with detergent (36.9%), but there was no significant difference among the treatments. The residue levels of pesticides during processing to jam decreased by 11.9-94.4% for etoxazole, fluopyram, procymidone, spiromesifen, and prochloraz, while the other pesticides were concentrated by boiling, or rather increased by 11.8-40.2%. However, when the residue levels were converted to residual amounts in consideration of the change in weight after processing, the residual amounts of the tested pesticides were reduced by 59.8-98.4% during processing. The processing factor (PF) were different for each pesticide, but PFs were < 1 for all washing solvents and methods, and 0.06-1.40 when processed into jam. CONCLUSION: To ensure the consumption of pesticide-free strawberry, the most efficient washing method is to immerse the strawberry in fresh water for few minutes, followed by rinsing them under running water.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.365-374
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• 2020

This study was conducted to monitor the residual pesticides on a total of 320 stalk and stem vegetables from January 2019 to December 2019 in the Incheon metropolitan area. Pesticide residues in samples were analyzed by the multi-residue method for 373 pesticides using GC-MS/MS, LC-MS/MS, GC-ECD, GC-NPD and HPLC-UVD. Risk assessment was also carried out based on the amount of stalk and stem vegetables consumed. The linearity correlation coefficient for the calibration curve was 0.9951 to 1.0000, LOD 0.002 to 0.022 mg/kg, LOQ 0.005 to 0.066 mg/kg and recovery was 82.0 to 108.0%. According to the monitoring of pesticides, 36 (11.3%) of 320 were detected with pesticide residues and 3 (0.9%) samples exceeded the maximum residual limit. The detection frequency for Chinese chives and Welsh onion was higher than that for other stalk and stem vegetables. The frequently detected pesticides were etofenprox, procymidone, fludioxonil, and pendimethalin. As a tool of risk assessment through the consumption of pesticide detectable agricultural products, the ratio of estimated daily intake (EDI) to acceptable daily intake (ADI) was calculated in the range of 0.0062-24.1423%. These results indicate that there is no particular health risk through consumption of commercial stalk and stem vegetables detected with pesticide residues.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.123-129
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• 2014

The present work was aimed to determine the pre-harvest residue limits (PHRLs) and the safety management of commonly used pesticides namely buprofezin and penthiopyrad on oriental melon (Cucumis melon var. makuwa). In this study, the buprofezin (diluted two thousand fold) and penthiopyrad (diluted four thousand fold) were sprayed single time on oriental melon in the cultivation areas Sangju (site 1) and Sungju (site 2). Oriental melon were randomly collected from the both areas at the end of 0 (2 hours after pesticides spaying), 1, 2, 3, 5, 7, 9 and 10 days. For analysis, each samples were partitioned twice (80 and 70 mL) with dichloromethane and purified by florisil SPE cartridge. Finally, the residual amounts of both pesticides in all samples were analyzed using gas chromatography/nitrogen phosphorus detector (GC/NPD). In this study, the method limit of quantification (MLOQ) for both buprofezin and penthiopyrad in oriental melon was found to be $0.01mg\;kg^{-1}$ and their recovery levels were 91.1~98.6% and 90.0~104.6%, respectively. Further, the calculated biological half-life for buprofezin and penthiopyrad in oriental melon were 3.9 and 3.5, and 3.0 and 2.7 days in site 1 and 2, respectively. The results of this study found that the PHRLs for buprofezin and penthiopyrad were 4.24 and $2.31mg\;kg^{-1}$, respectively at 10 days before harvest. Consequently, the present study suggest that the residual amounts of both pesticides will be lower than the maximum residue limits (MRLs) when oriental melon is harvested.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.154-163
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• 2007

In order to elucidate the residual characteristics of some pyrethroid insecticides commonly used for Korean cabbage, such as bifentbrin, lambda-cyhalothrin and deltametbrin, the test pesticides were sprayed onto the crop at recommended rate and doubled rate of the recommendation. Their detection limits were 0.004 mg $kg^{-1}$ and mean recoveries at the fortification levels of 0.04 and 0.2 mg $kg^{-1}$ were from 95.16 to 99.32 and from 86.81 to 103.73%, respectively. Half-lives were from 2.5 to 3.6 at the recommended rate and from 2.3 to 3.9 days at the doubled rate of the recommendation. Initial residue amounts of bifenthrin and lambda-cyhalothrin at the recommended rate and doubled rate of recommendation and of deltamethrin at the recommended rate were less than their MRL, whereas, in case of deltamethrin sprayed at doubled rate of the recommendation, the residue level exceeded its MRL. However, the residue levels of the pesticides in the crop sampled at harvest were less than their maximum residue levels and the ratios of the estimated daily intake (EDI) to acceptable daily intake (ADI) for the pesticides tested calculated from the residue data at harvest were less than 7%, suggesting that these pesticides would be safe for Korean cabbage from the residue concern.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.340-347
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• 2019

We performed a safety survey on residual pesticides in dried agricultural products. A total of 110 samples of dried agricultural products distributed in Gyeonggi-do were analyzed for 263 pesticides according to multi class pesiticide multiresidue method. Ten types of pesticides were detected in 10 samples. Chlorpyrifos was detected in Ricinus communis leaves, chlorpyrifos, hexaconazole, pyridalyl in Chwinamul (wild aster), diniconazole, isoprothiolane, lufenuron in radish leaves, hexaconazole in Cirsium setidens (Korean thistle), bifenthrin, and chlorothalonil, boscalid, and pyraclostrobin in pepper leaves. The detection rate of pesticides was 9.1%, and among these samples, one was detected over Maximum Residue Limits (MRLs). In the validation study, the values of limit of detection (LOD), limit of quantitation (LOQ), coefficient of determination ($R^2$) and recovery were in the range of 0.002~0.027 mg/kg, 0.006~0.083 mg/kg, 0.9964~1.0000 and 74.8~118.9%, respectively. The Positive List System (PLS) was newly introduced as part of the safety management of residual pesticide in agricultural products in Korea in 2019. With the application of the PLS, if the MRL is not established, 0.01 mg/kg limit is applied uniformly. In spite, these of strengthened residue limits, the MRLs of dried agricultural products are still insufficient. Therefore, this study could be utilized as basic data for the setting of proper MRLs.

• Korean Journal of Pharmacognosy
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• v.38 no.3 s.150
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• pp.205-216
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• 2007

South Korea is the representative consumption country of herbal medicines and most of herbal medicines circulating in Korea have been importing from the developing countries of Southeast Asia such as China, Vietnam, Indonesia and so forth. Domestic hygiene and safety are continuously proposed because herbal medicines which are circulating have the possibility could remain contaminants or residues. Physicochemical contaminants such as heavy metals, persistent organic pollutants, radionucleosides, microbial toxins, biological contaminants such as microorganisms and animals, agrochemical residues such as pesticides, substances used for fumigation, antiviral agents, and solvent residues are classified as major contaminants and residues in herbal medicines from 2005 September WHO.$^{1)}$ Currently our administration have established a permission standard and the inspection criteria against the heavy metal, the residual pesticides and a residual sulfur dioxide. Furthermore our administration is continuously monitoring and conducting researches for the policies and their scientific ground against herbal medicines. But the appearances or discoveries of the harmful new species due to environmental and industrial developments are becoming social problems. Therefore it may be necessary to continuously consider and investigate regarding hereupon. Recently, the contamination of the mycotoxins against foods such as cereals, nuts and the powdered red pepper have developed and started became problematic issue, and possibility of contamination against the herbal medicine is proposed. And since populations who are using the herbal medicines very limited to several nations, recognition and researches about contamination of mycotoxins in herbal medicines are very insufficient. Therefore it will be need to more focus on the international regulation of quality control and safety for herbal medicines. Now on, we are going to introduce the importance, occurrence, characteristic properties, World-wide research trends and detoxification of aflatoxins, which is known as the most potent mutagen, carcinogen and teratogen mycotoxins.