• Korean Journal of Organic Agriculture
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• v.30 no.2
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• pp.207-230
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• 2022

A survey on the understanding of environment-friendly certification system was conducted for certified operators. The survey included the necessity of certification system, difficulties in producing certified products, and general evaluation of the current certification system. Certified operators were generally satisfied with the certification system in terms of the certification standards, the public subsidy programs, and the farm management costs. Individuals with parallel production farms were relatively less satisfied than the group with full-time organic farmers. Analysis using the ranking probit model indicated that the longer the certification experience, the more highly aware the need for the certification system was. Our results indicated that policy strategies are needed to enlarge the marketability of environment-friendly agricultural products since economic factors of organic products were the most important factor for maintaining and expanding certification in overseas as well as in Korea. It seems to be necessary to implement economic triggers for certified operators to continue their certification programs by promoting the transition period certification for individual farms in parallel with conventional agriculture. Analysis of the variables correlated with the expansion of environment-friendly agriculture by the logit model implied that certified operators with the younger age and higher annual incomes were more likely to expand environment-friendly agriculture. Therefore, it might also be important to provide financial support and incentives for new entry farmers to participate in environment-friendly agriculture and establish a system to share the know-how of successful certified organic farmers.

• Honam Mathematical Journal
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• v.30 no.3
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• pp.521-533
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• 2008

We investigate a periodically forced Lotka-Volterra type predator-prey system with impulsive perturbations - seasonal effects on the prey, periodic releasing of natural enemies(predator) and spraying pesticide at the same fixed times. We show that the solutions of the system are bounded using the comparison theorems and find conditions for the stability of a stable prey-free solution and for the permanence of the system.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.381-393
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• 2010

In order to monitor the residual characteristics of the pesticides in leafy vegetables selling at wholesale markets and traditional markets in Cheongju, a total of 180 samples of 15 leafy vegetables, such as broccoli, celery, chard, chicory, Chinese vegetable, Chwinamul, crown daisy, Korean cabbage, leek, lettuce, perilla leaves, Shinsuncho, spinach, welsh onion and young radish, were purchased from the wholesale markets and traditional markets in June and August in 2010 and the pesticide residues in them were analyzed by multiresidue analysis method using GLC, HPLC and GC-MSD. Seven pesticides were detected from 12 samples out of total 180 samples collected, representing detection rate was 6.7%. In case of the samples collected from markets in June, four pesticides including tefluthrin were detected from six samples and in case of the samples collected from markets in August, three pesticides including pendimethalin were detected from three samples. The MRL-exceeding rate of pesticides detected from leafy vegetables was 0.6%. The pesticide exceeded its MRL was azoxystrobin detected from crown daisy and many pesticides were not registered to the crops, excepting that azoxystrobin detected from Chwinamul and tefluthrin from leek. Estimated daily intakes (EDIs) of the pesticides detected from leafy vegetables were less than 7% of their acceptable daily intakes (ADIs), representing that residue levels of the pesticides detected were evaluated as safe.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.237-245
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• 2007

We tested for residual pesticide levels in agricultural products purchased from 5 provinces within the middle region of Korea during 2006. A Total of 488 samples of 23 different types of agricultural products were analyzed by GC/MS, GC-NPD, and LC/MS/MS. We used multi-analysis methods to analyze for 231 different pesticide types; a single residual pesticides were detected in 92 samples (18.9%), of which 9 samples (1.9%) exceeded the Korea Maximum Residue Limits (MRLs). we detected pesticide residue in more than 50% of the pepper leaf and welsh onion samples. For the welsh onions, 16 among the 30 analyzed samples contained pesticide residue, and 4 samples exceeded the Korea MRLs. Among the 234 kinds of pesticides we tested for, 42 were detected, and 21 of them were detected more than twice. Six pesticide residue types, including cypermethrin, iprodione, fludioxonil, ethoprophos, flutolanil, and lufenuron, exceeded the MRLs. No residual pesticides were detected in 396 of the samples (81.1%), and the residual pesticide levels in 83 samples (17.0%) were lower than the Korea MRLs, indicating that 98.1% of the samples were relatively safe.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.216-222
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• 2009

The present study aims to monitor pesticide residues in cut flowers collected from the farms and markets. Cut flowers used in this study included rose, lily and chrysanthemum collected from June to September, 2008. Samples were collected once from farms in Hwasung, Goyang (Gyeonggi-do), Inje (Gangwon-do) and thrice from wholesale market in Namdaemunm, Yangjae and Gangnam (Seoul). Total of 24 pesticides (12 fungicides, 11 pesticides and 1 acaricide) were detected from samples collected from farm and total of 64 pesticides (25 fungicides, 36 pesticides, 1 acaricide and 2 fungicides) were detected from samples collected from wholesale market. The highest detection frequency of pesticide from farm was for carbaryl (15%) and for boscalid, fluacrypyrin, fluquinconazole, methomyl, pyraclostrobin, trifloxystrohin (10%), with overall detection of $0.1-36.99\;mg\;kg^{-1}$. While the highest detection frequency of pesticides from wholesale market was for carbaryl, fluquinoconazole and kresoxim-methyl (18.52%), methomyl (16.6%), and methiocarb and thiacloprid (12.96%) with overall detection amount of $0.1-56.2\;mg\;kg^{-1}$. Higher amount of pesticides were detected in leaves than in flowers. Among the pesticides detected, detection frequency of unregistered pesticides for rose, chrysanthemum and lily was 55%, 60% and 63% collected from farms and 47%, 60% and 89% collected from markets, respectively. These pesticides require registration and further monitoring in floricultural crops.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.391-402
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• 2013

Pesticide residues in agricultural products in Korea were evaluated to create a data base to inform food policy. Pesticide residues were investigated in 17 commodities collected from 9 provinces in 2012. Our analytical method of multiresidue analysis, involved the analysis of individual recovery, linearity, limit of detection, and limit of quantitation of 60 pesticides in six matrices. The pesticides, including acetamiprid and forchlorofenuron, were evaluated in 358 agricultural samples by liquid chromatography/tandem mass spectrometry. Twenty three pesticides were detected from 67 samples. The results showed that the ratio of estimated daily intake to acceptable daily intake was 0.00009-0.0861% by the intake assessment, which means that residual pesticides in agricultural products in Korea are properly controlled.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.283-289
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• 2019

This study was performed to monitor the residual pesticides in agricultural products used in school foodservice in the Gwangju metropolitan area. Risk assessment was also carried out based on the amount of agricultural products consumed. A total of 320 agricultural products supplied to schools in Gwangju were analyzed from 2015 to 2017. The pre-treatment and residual pesticide analysis of these products was conducted in accordance with the second method for multi-residue analysis of pesticides in the Korean food code. The hazard index was calculated by dividing the estimated daily intake (EDI) of pesticides by the acceptable daily intake (ADI). The linearity correlation coefficient for the calibration curve was 0.9923 to 1.0000, LOD 0.004 to 0.019 mg/kg, LOQ 0.012 to 0.057 mg/kg, and recovery was 79.1 to 100.2%. Residual pesticides were detected in 18 (5.6%) of 320 agricultural products used for school foodservice, and one sample of sweet potato stem (0.3%) exceeded the maximum residual limit (MRL). The detection frequency for chili peppers and bell peppers was higher than that for other agricultural products. The frequently-detected pesticides were boscalid and acetamiprid. These results showed that residual pesticide management is needed for chili pepper, bell pepper and sweet potato stem among agricultural products supplied to schools. The hazard index of bifenthrin in sweet potato stem showed the highest (64.18%), and the other pesticides were 0.03-8.23%. These results indicated that agricultural products supplied to schools in Gwangju were safe for consumption. To minimize the intake of residual pesticides, it is necessary to not only thoroughly wash agricultural products but to also ensure the expanded supply of products that are pesticide-free.

• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.84-93
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• 2013

Validated analytical methods for isopyrazam are meager or lacking. In the present study, a single residual analytical method was developed for isopyrazam in selected commodities. Isopyrazam was analyzed in brown rice, soybean, green pepper, mandarin, cucumber, and Korean melon. We tried different solvents and methods through extraction, partition and purification steps to obtain best analytical results. For isopyrazam samples were extracted with acetonitrile, concentrated and partitioned with n-hexane, clean-up using florisil with n-hexane/ethylacetate (70/30) and analyzed with HPLC/UVD. The limit of quantitation (LOQ) for isopyrazam was 1.0 ng (S/N > 10) and method LOQ (MLOQ) was 0.04 mg $kg^{-1}$. Recovery ranged through 81.0~105.3% (syn-isomer) and 80.8~105.6% (anti-isomer) at fortification level of 0.04 (MLOQ), 0.4 (10 ${\times}$ MLOQ), and 2.0 (50 ${\times}$ MLOQ). The coefficient of variation (CV) for isopyrazam was less than 10% regardless of sample types. These results were further confirmed with LC/MS, respectively. The proposed method is highly reproducible and sensitive and is suitable for routine analysis.

• Journal of The Korean Society of Clinical Toxicology
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• v.17 no.2
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• pp.108-117
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• 2019

Purpose: The study examined the poisoned patients' characteristics nationwide in Korea by using data from the National Emergency Department Information System (NEDIS). Methods: Among the patients' information sent to NEDIS from January 1, 2013 to December 31, 2015, the included subjects' main diagnosis in ED showed poisoning according to the 7th edition of the Korean Standard Disease Classification (KCD-7). We analyzed the patients' gender, age, initial vital signs, visit time, stay time of staying in ED, results of ED care, main diagnosis in ED, length of hospitalization, and results of hospitalization. Results: A total of 106,779 ED visits were included in the analysis. There were 55,878 males (52.3%), which was more than the number of females. The number of intentional poisoning was 49,805 (59.6%). 75,499 cases (70.8%) were discharged, and 25,858 cases (24.2%) were hospitalized. The numbers of poisoning patients per 1,000 ED visits were 14 in Chungnam and 11.9 in Jeonbuk. The most common cause of poisoning, according to the main diagnosis, was venomous animals. It was the same for hospitalized patients, and pesticide was next. Pesticide was the most common cause of mortality in ED (228 cases, 46.1%) and after hospitalization (584 cases, 54.9%). The incidence of poisoning by age group was frequent for patients in their 30s to 50s, and mortality in ED and post-hospitalization were frequent for patients in their 60s to 80s. Conclusion: This study investigated the characteristics of poisoning patients reported in the past 3 years. Pesticide poisoning had a high mortality rate for patients in ED and in-hospital. For mortality, there was a high proportion of elderly people over 60. Thus, policy and medical measures are needed to reduce this problem. Since it is difficult to identify the poison substance in detail due to nature of this study, it is necessary to build a database and monitoring system for monitoring the causative substance and enacting countermeasures.

• Smart Media Journal
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• v.9 no.4
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• pp.176-186
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• 2020

The size and shape of crops are diverse, and the growing environment is also different. Therefore, when one uses a drone to spray pesticides, the characteristics of each crop must be considered, and flight conditions such as the flight height and forwarding velocity of the drone should be changed. The droplet flow of pesticides is affected by various flight conditions, and a large change occurs in the sprayed area. As a result, an uneven distribution of liquid may be formed at the wake, and the transport efficiency will be decreased as well as there would be a risk of toxic scatter. Therefore, this paper analyzes the degree of distribution of pesticides to the crops through numerical analysis when pesticide is sprayed onto the selected three crops with different characteristics by using agricultural drones with different flight conditions. On the purpose of establishing a guideline for spraying pesticides using a drone in accordance with the characteristics of crops, this paper compares the amount of pesticides distributed in the crops at the wake of nozzle flow using the figure of merit, and the sum of transported liquid rate divided by the root mean square of the probability density function.