Jang-Eok Kim

Interaction of reactive and inert chemicals in the presence of oxidoreductases: reaction of the herbicide bentazon and its metabolites with humic monomers.

The herbicide bentazon (3-isopropyl-1H-2,1,3-benzothiadiazine-4(3 H)-one-2,2-dioxide), a relatively inert chemical, and some of its metabolites were incubated with a laccase or a peroxidase in the presence or absence of humic monomers to evaluate the incorporation of the herbicide and its metabolites into humic material by oxidative enzymes. Guaiacol and ferulic acid were used as representative electron donor co-substrates in most of the oxidative coupling reactions. Bentazon and its metabolites, with the exception of hydroxy metabolites, underwent little or no transformation by the two enzymes in the absence of guaiacol and ferulic acid,but in the presence of these co-substrates transformation occurred. The reaction of bentazon with guaiacol in the presence of the laccase or a peroxidase was almost complete in30 min. 6-Hydroxy- and 8-hydroxy-bentazon were completely transformed by each enzyme both with and with out co-substrates. At pH 3.0 and in the presence of laccase and guaiacol, the concentrations of bentazon and its metabolites2-amino-N-isopropyl-benzamide (AIBA), des-isopropyl-bentazon and 8-chloro-bentazon decreased by 27, 57, 20 and 4%,respectively. The corresponding levels of transformation with peroxidase at pH 3.0 were 9, 70, 30 and 5%, respectively. The extent of transformation decreased with increasing pH. At low pH, the hydroxy-bentazons were completely transformed,followed by (in order of percentage transformation) AIBA,des-isopropyl-bentazon, bentazon and 8-chloro-bentazon. Transformation of bentazon by the laccase increased with increasing guaiacol concentration. In the presence of the peroxidase, the most effective co-substrates for transformation of bentazon were (in decreasing order) catechol, vanillicacid, protocatechuic acid, syring aldehyde and caffeic acid,while in the presence of the laccase, catechol was most effective, followed by caffeic acid, protocatechuic acid and syringaldehyde.

Monitoring of Pesticide Residues and Risk Assessment for Fruit Vegetables and Root Vegetables of Environment-friendly Certified and General Agricultural Products

BACKGROUND: This study was conducted to monitor the residue of pesticides and to assess their risk in domestic agricultural products, such as fruit vegetables, tomatoes, oriental melons and root vegetables, garlic, potatoes and onions. METHODS AND RESULTS: 250 samples containing both general and environment-friendly certified agricultural products were collected from traditional markets and supermarkets in 6 cities. 132 pesticides except for herbicides were analysed using the multi-residue methods by GC/ECD, GC/NPD and HPLC/UVD. 17 kinds of pesticides were detected from 42 samples, which were 32 general, 1 organic, 4 pesticide-free and 5 low pesticide agricultural products. Among those, myclobutanil detected in 1 potato and procymidone detected in 10 oriental melons were unregistered pesticides for using in Korea. Fenbuconazole detected in 1 potato and phorate detected in 1 tomato were exceeded over the MRLs established by Korea Food and Drug Administration. CONCLUSION: Based on these results, a risk assesment was conducted using a percentage of acceptable daily intake(%ADI). %ADI ranged from 0.0064% to 4.6035%, and showed these values have no effect on human health.

Monitoring of Pesticide Residues and Risk Assessment for Cereals and Leafy Vegetables of Certificated and General Agricultural Products

BACKGROUND: This study was conducted to monitor the current status of pesticide residues and to assess their risk in domestic agricultural products. The samples were rice, barley, lettuce and perilla leaf. These four types of agricultural products were those with GAP(Good Agricultural Practice) certification, organic agricultural products, pesticide-free agricultural products or general agricultural products. METHODS AND RESULTS: They were purchased from traditional markets and supermarkets of 12 regions in Korea from July to August 2010. The total number of samples was 259 for agricultural products and these were analyzed by GC/ECD, GC/NPD and GC/MSD. We used multiresidue methods to analyze for 110 different pesticides except for herbicides. CONCLUSION: In this study, residual pesticides were detected in 18 samples. Among these general agricultural products, organic agricultural products and products with GAP-certification were detected in 12, 4 and 2 samples, respectively. Detection rates of general agricultural products, organic agricultural products and products with GAP- certification were 4.6%, 1.5% and 0.8% respectively. Pesticides were not detected in pesticide-free agricultural products. Their detection levels were less than their maximum residue levels. Their estimated daily intakes ranged from 0.0003% to 0.04302% of their acceptable daily intakes, of which the values have no effect on human health.

Establishment of Safe Management Guideline Based on Uptake Pattern of Pesticide Residue from Soil by Radish

Received: 28 October 2016 / Revised: 7 November 2016 / Accepted: 10 November 2016 Copyright c 2016 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ORCID

Application of Multiresidue Analysis Method of Unregistered Pesticides in Korea for Imported Food

BACKGROUND: Recently in Korea, the import of agricultural products is rising due to the increasing amount of trade. Unregistered pesticides, allidochlor, propachlor, propham, cycloate, diallate and pebulate are widely used as pesticides for rice cultivation in foreign countries, while they are not registered in Korea. Therefore, the residue amount of imported agri-foods should be verified using the proper official analytical method for each of them that has not registered in Korea. METHODS AND RESULTS: This work was conducted to apply the official method of Korea Food & Drug Administration (KFDA) for determining multi class pesticide multiresidues in agricultural commodities. Brown rice and orange which have different characteristics as a matrix were selected as representative samples for residue analysis. The recoveries of cycloate, diallate and pebulate by GC/MS in fortified brown rice and orange with levels of 0.04~0.4 mg/kg were ranged from 82.8% to 110.3%. The quantification limits of three pesticides in brown rice and orange were 0.04 mg/kg. CONCLUSION: As a result, this method can surely be used as an official method for routine analysis of unregistered pesticides in Korea for imported agri-food.

Monitoring of Pesticide Residues and Risk Assessment for Fruits in Market

BACKGROUND: This study was conducted to monitor residual pesticides in domestic agricultural products and to assess their risk to human health. METHODS AND RESULTS: 123 samples containing both general and environment-friendly certified agricultural products were purchased from traditional domestic markets and supermarkets in six provinces of Korea. Multiresidue analyses of one hundred twenty-two pesticides except for herbicides were performed with gas chromatography-electron capture detector, gas chromatography-nitrogen/phosphorus detector, and high-performance liquid chromatography. Sixteen pesticides were detected in 45 agricultural product samples, which were 38 general, 6 low pesticide and 1 of GAP agricultural product samples and the detection rate was 33.6%. Pesticides detected in agricultural product samples were cypermethrin, lufenuron, fenvalerate, bifenthrin, chlorfenapyr and iprodione. Residual concentration of 18 samples were exceeded the recommended maximum residue limit set by Ministry of Food and Drug Safety and two kinds of unregistered pesticides in korea were also detected in two samples. CONCLUSION(S): In order to do risk assessment by agricultural products consumption, estimated daily intake of residual pesticides were determined and compared to acceptable daily intake, referring to %ADI values. The range of %ADI values was from 0.038% to 2.748%. Taken together, it demonstrates the pesticides found in agricultural products samples were below the safety margin, indicating no effect on human health.

Application of Macroporous Diatomaceous Earth Column for Residue Analysis of Insecticide Endosulfan in Herbal Medicines

Application of Macroporous Diatomaceous Earth Column for Residue Analysis of Insecticide Endosulfan in Herbal Medicines Jeong-In Hwang, Young-Hwan Jeon, Hyo-Young Kim, Ji-Hwan Kim, Yoon-Jeong Lee, Ju-Young Park, Do-Hoon Kim and Jang-Eok Kim (School of Applied Biosciences, Kyungpook National University, Daegu 702-701, Korea, Division of Herbal Medicine Research, Korea Food and Drug Administration, Osong 363-951, Korea)

Monitoring of Pesticide Residues and Risk Assessment for Medicinal Plants

This study was conducted to monitor residual pesticides in ginseng and balloon flower roots and to assess their risk to human health. All of 112 samples consisted of ginseng and balloon roots were purchased from traditional domestic markets and supermarkets in nine provinces of Korea in 2012. Multi-residue analysis of 122 pes- ticides was conducted and the analysis was performed by gas chromatography-electron capture detector, gas chroma- tography-nitrogen/phosphorus detector, and high-performance liquid chromatography. Seven pesticides were detected in 12 root samples and the detection rate was 10.7%. The detected twelve root samples were 10 ginseng root samples and 2 balloon root samples. Pesticides detected in root samples were procymidone, kresoxim-methyl, endosulfan, cypermethrin, tralomethrin, tetraconazole and chlorfluazuron. Among them, two pesticides as tetraconazole in a bal- loon flower root and cypermethrin in a ginseng root exceeded the recommended maximum residue limit set by Korea Food and Drug Administration. Five pesticides detected from 10 root samples were identified as unregistered pesti- cides in Korea. In order to do risk assessment with Korean medicinal plant consumption, estimated daily intake of residual pesticides were determined and compared to acceptable daily intake, referring to %ADI values. The range of %ADI values was from 0.006% to 0.333%. Taken together, it demonstrates the pesticides found in the two root sam- ples were below the safety margin, indicating no effect on human health.

Multiresidue Analysis Method for Determination of Unregistered Organophosphorus Pesticides in Korea for Imported Agri-Food

BACKGROUND: For safety evaluation of imported agri-food in Korea, the multiresidue analysis method was establised for unregistered organophosphorus pesticides, aspon, chlorthion, chlorthiophos, crotoxyphos, demeton-O, demeton-S, demeton-S-methyl, dioxathion, heptenophos, iodofenphos, leptophos, methyl-trithion, propetamphos and sulfotep. METHODS AND RESULTS: The used method for multiresidue analysis in brown rice and orange used as representative samples of imported agri-food was the official method of Korean Food and Drug Administration. The results of validation test of 13 organophosphorus pesticides except crotoxyphos for multiresidue analysis method are compared to the criteria such as specificity, linearity, accuracy, precision and limit of quantification. CONCLUSION: The used method for multiresidue analysis of unregistered 13 organophosphorus pesticides except crotoxyphos in Korea can surely be used as an official method for routine analysis of imported agri-food.

Biodegradation of Fungicide Tolclofos-methyl by Sphingomonas sp. 224

In order to decrease level of an organophosphorus fungicide, tolclofos-methyl, from in situ ginseng cultivating soil, we isolated a tolclofos-methyl degrading bacteria from ginseng cultivating soil samples. The bacterial strain removed tolclofos-methyl around 95% after 3 days incubation with complete liquid media. The strain was identified as Sphingomonas sp. by 16S rDNA sequence comparison, and designated as Sphingomonas sp. 224. Through the GC-MS analysis, Sphingomonas sp. 224 was proposed to have an initiative degradation pathway generating the metabolite such as 2,6-dichloro-4-methyl phenol compound from tolclofos-methyl. In addition, Sphingomonas sp. 224 was confirmed representing the effective degrading capability to tolclofosmethyl in situ soil.