• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.95-100
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• 2022

BACKGROUND: This study was aimed to determine characteristics of residues of the soil-treated boscalid and pyraclostrobin within Hylomecon vernalis and to evaluate the risks from intake of the residual pesticides in the crop. METHODS AND RESULTS: The pesticides were treated to soils at two different concentrations, and the plant samples were collected 57 days after seeding. The samples were extracted using the QuEChERS extraction kit (MgSO₄ 4 g, NaCl 1 g). The quantitative methods for boscalid and pyraclostrobin were validated using linearity, recovery, and CV (coefficient of variation). Risk assessment of the pesticides was performed using Korea national nutrition statistics 2019. CONCLUSION(S): The residual levels of boscalid were 0.02-0.05 mg/kg (for the treatment at 6 Kg/10a) and 0.05-0.08 mg/kg (for the treatment at 12 Kg/10a), respectively. The residual concentrations of pyraclostrobin were below the LOQ. The amounts of pesticides were less than Maximum Residue Limits specified by the Korean Ministry of Food and Drug Safety. The maximum hazard indices of boscalid in chwinamul and amaranth for consumers were 0.0075% and 0.1525%, respectively, and it indicates that the risk of the pesticides from the crop is considered to be low.

• The Korean Journal of Pesticide Science
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• v.18 no.1
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• pp.1-7
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• 2014

The present study was performed to investigate the pre-harvest residue limit (PHRL) of pesticides namely, metalaxyl-M and flusilazole in oriental melon, and to identify the biological half-life and characteristics of their residues. In this study, pesticides were sprayed once as single spray and double spray on oriental melon. The oriental melon samples were collected at 0, 1, 2, 3, 5, 7, 9 and 11 days before harvest and samples were extracted with QuEChERS method. The residues of both the pesticides were quantified using GC/NPD and LC/MS/MS. The limit of detection was found to be 0.02 mg/kg and 0.01 mg/kg and their recoveries were greater than 95% (95.7% ~ 103.2% for metalaxyl-M and 100.2% ~ 106.8% for flusilazole) for both pesticides. The biological half-lives of both metalaxyl-M and flusilazole were 12 days at single and double spray, respectively. The PHRL of metalaxyl-M and flusilazole was found 1.0 mg/kg and 0.3 mg/kg, respectively for 10 days before harvest. The results of the present study shows the residual level of both the pesticides metalaxyl-M and flusilazole in oriental melon were less than their maximum residual limits.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.166-172
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• 2011

BACKGROUND: Food Sanitary Act establishes Maximum Residue Limits (MRLs) of pesticides in food that are newly registered and used per each quarter, as stipulated by Agro-chemical Control Act. Current Food Code contains the MRLs for a total of 418 pesticides in 184 food types. METHODS AND RESULTS: National MRLs for pesticides have been established by based on scientific data of good agricultural practice, acceptable daily intake (ADI), food intake, average body weight and others. MRLs for pesticides are generally set under the principle that theoretical maximum daily intake (TMDI) are always below ADI. As results, 27 MRLs in agricultural products were newly proposed for 22 pesticides (fungicide: azoxystrobin, fludioxonil, fluquinconazole, flusilazole, iprovalicarb, kresoxim-methyl, mandipropamid, metconazole, pyraclostrobin, tebuconazole, triflumizole, etc., Insecticide: dinotefuran, flubendiamide, indoxacarb, cyhalothrin, spinetoram, thiacloprid, thiamethoxam, metaflumizone, etc., Acaricide(miticide): cyenopyrafen, lufenuron) in 2010. CONCLUSION(s): There is no intake concerns for establishment of pesticide MRLs on foods in this time. Because the ratio of theoretical maximum daily intake (TMDI) are set below that of ADI.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.50-56
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• 2017

BACKGROUND: The present study was carried out to identify the residue patterns of insecticide pyridalyl and fungicide fluopicolide in watermelon and calculate the biological half-lives for establishing the pre-harvest residue limits (PHRLs). METHODSANDRESULTS:The watermelon samples for residue analysis were harvested 7 times during 0~10 days (Field 1) and 0~20 days (Field 2) after treatment of pesticides on watermelon in two different fields at the recommended dose, respectively. The residue analysis was conducted with HPLC/UVD. The method limit of quantitation (MLOQ) were set at 0.05 and 0.02 mg/kg, respectively, and overall mean recoveries were 81.2~90.5% for pyridalyl and fluopicolide. The residues in sample were stable for 43~47 days. The initial residue amount in field 1 and 2 were 0.12~0.16 mg/kg for pyridalyl and 0.23~0.24 mg/kg for fluopicolide, which were below maximum residue limit (MRL). The biological half-lives in field 1 and 2 were 26.9 and 17.9 days for pyridalyl and 16.6 and 94.2 days for fluopicolide, respectively. CONCLUSION: The PHRL for watermelon were estimated as 0.21 and 1.03 mg/kg for pyridalyl and flopicolide at 10 days before harvesting. The residue patterns of pyridalyl and fluopicolide were characterized by a very slow decrease of residue levels in watermelon.

• Korean Journal of Environmental Agriculture
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• v.31 no.3
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• pp.271-276
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• 2012

BACKGROUND: It is hard to control the agricultural products exceeding MRL (maximum residue limit) before forwarding. Therefore, NAQS (National Agricultural Products Quality Management Service, South Korea) established PHRL (pre-harvest residue limit) on agricultural products during their cultivation periods. This study was performed to set the PHRLs of peach during cultivation period, and also to estimate biological half-lives for residues of clothianidin and fluquinconazole. METHODS AND RESULTS: Two groups of peach were treated under Korean GAP (Good Agricultural Practices) with application time, single and triple treatments. Sample was collected over 14days (each after 0, 2, 4, 6, 8, 10, 12, 14 days. 8times), and clothianidin and fluquinconazole were analyzed by HPLC/DAD and GC/ECD, respectively. CONCLUSION: The biological half-life of clothianidin in single treatment and triple treatment was 5.2days and 7.0days. That of fluquinconazole was also 3.9days and 4.1days, respectively. The PHRL of peach on 10days before harvest was 1.4 mg/kg in clothianidin and 1.8 mg/kg in fluquinconazole.

• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.203-213
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• 2005

Oxytetracycline, tetracycline, chlortetracycline and doxycycline in honey were separated by solid phase extraction (SPE) and determined with high performance liquid chromatography (HPLC) with UV/Visible detector. Analysis was carried out using following conditions: XTerra $C_8$ column $(3.9\times150mm\;i.d. 5{\mu}m)$, mobile phase composed of 0.01M oxalic acid : methanol : acetonitrile (820 : 80 : 100, v/v/v), isocratic pump at a flow rate of 0.9 ml/min. and $50{\mu}l$ of injection volume, UV/Visible detector with wavelength of 360nm. The calibration curves of four tetracyclines showed linearity $(\gamma^2>0.999)$ at concentration range of $100\~1,000 ng/ml$. The recoveries in fortified honey represented more than $70\%$ with low coefficient of variation $(<10\%)$ for concentration range of four tetracyclines. The detection limits for oxytetracycline, tetracycline, chlortetracycline and doxycycline were 13.8, 14.6, 26.2 and 24.9ng/g in acacia honey. respectively. We also monitored tetracyclines residue in domestic honey [n : 38, acacia (20), wild flower (18) ] and foreign honey [n=22, legally distributed (13), illegally distributed (9)] using modified Charm II screening and HPLC confirmation methods. Seven of the 60 samples $(11.7\%)$ were suspect positive using modified Charm II screening test. Chlortetracycline residue was found in one foreign honey (illegally distributed) tested at concentrations of 0.22 ppm. Conclusively, for more effective control of tetracyclines used in beekeeping should be further survey for residues in honey and also national guidelines (maximum residue limit : MRL) and methods should be obligatory.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.618-624
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• 1995

In order to evaluate the acceptability of Korea and Codex maximum residue limits (MRLs), theoretical maximum daily intake (TMDI) by Korean population was calculated from MRL and food factor and compared with acceptable daily intake (ADI). The percent ratio of TMDI to ADI for 105 pesticides whose MRL was established in Korea was mostly below 80% and 13 pesticides exceeded the ADI. Among 82 pesticides with Codex MRL, 20 items exceeded the ADI. The main causes of exceeding the ADI according to Korea or Codex MRLs were pointed out for 22 items and it was needed to set measures to assure a safety margin.

• The Korean Journal of Pesticide Science
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• v.18 no.2
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• pp.61-68
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• 2014

Dissipation constants and half-lives of acaricides etoxazole and flufenoxuron in apples were calculated to establish their pre-harvest residue limits (PHRLs). The acaricides were sprayed on apples with single and triple doses based on safe use guidelines, and their residual patterns in the apple were interpreted using first order kinetics equation. The residual amounts of acaricides during the experimental period were below their maximum residue limits (MRL) for apple. The dissipation constants of acaricides in the apples were calculated at 0.0788 for etoxazole and 0.0319 for flufenoxuron corresponding to their biological half-lives; 8.8~21.7 days for etoxazole and 21.7~23.1 days for flufenoxuron. The PHRLs of acaricides in the apple showed the residual amounts of etoxazole and flufenoxuron at the harvesting date would be below their MRLs if their residual amounts were less than 0.87 and 0.88 mg/kg, respectively, at 7 days prior to harvesting the apples.

• 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.14 no.2
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• pp.86-94
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• 2010

This study was conducted to monitor the current status of pesticide residues in agricultural products before auction at whole markets in Busan area from March 2006 to December 2008. Of the 7,237 samples that were analyzed by multiresidue methods, 1,164 samples (16.1%) had pesticide residues and 231 samples (3.2%) exceeded the maximum residue limits (MRLs). 181 samples of the 231 samples exceeding MRLs were applied to the tentative limits because the use of the pesticides for the agricultural products was not established against the MRLs in the Korea Food Code, and it is equivalent to 78.4%. The order of pesticides exceeding MRLs was endosulfan, procymidone, chlorothalonil, ethoprophos, chlorpyrifos, diethofencarb, kresoxim-methyl and EPN. Of 211 samples with two or more pesticides residues, the residues exceeded the MRLs in 80 samples and it is equivalent to 37.9%. This study results suggested that pesticide residues exceeding MRLs could be attributed to the use of inapplicable pesticides for agricultural products and the use of two or more pesticides.