• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.377-387
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• 1997

Primary fluorescence characteristics of ten standard solutions of organophosphates, sea water, and water from agricultural land were investigated by fluorescence contour. All the standard solutions of organophosphates has shown characteristics countours. Their emission maxima were shown between 296 nm and 437 nm. According to their numbers of emission maxima on the fluorescence contours, the organophosphates can be categorized in two different groups. Ateric and Diazinon are the first group with two emission maxima. DDVP with other seven standard organophosphates belong to the second group. The second group has two subgroups. One is characterized by the similar emission and excitation maxima, which are 310 nm and 280 nm, respectively. Those are DDVP, Hinosan, Kitazin, Locsion, Meta. The other sub-group shows quite different emission and excitation maxima from the first sub-group. They are Monopho, Thaconyl and Gropho and their emisson maxima were in far longer (437 nm) or shorter wavelength (296 nm). From agricutural samples, one of the investigated organophosphates was detetected by its characteristic retention time $(t_r=12min)$. HPIC-fluorescence data gave an additional parameter for differentiation between two organophosphates which has similar excitation and emission maxima.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.292-302
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• 2005

Condition of Ion-Trap gas chromatography-mass spectrometry (GC-MS) for rapid screening of 206-pesticides residues in agricultural foodstuffs was optimized. As applying a wide-bore column (10 m${\times}$0.53 mm, DF 0.25 um) connected with a fused silica restrictor (0.6 m${\times}$0.1 mm), a significant retention time reduction was obtained. Additionally, the shape of peaks was sharper and higher than classical GC's and GC-MS's, which allowed lower detection limits. To easily manage many spectral data, both of Electron Ionization(EI) and Chemical Ionization(CI) techniques were adopted in screening procedure. At the following steps, MS-MS technique were used to confirm screened analytes in complicated matrices.

• Journal of Food Hygiene and Safety
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• v.17 no.3
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• pp.137-145
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• 2002

Tributyltin compounds have been increasingly used in the form of plastic stabilizers, catalytic agents, industrial agricultural biocides, antifouling paint, and pesticides. Among these organotin compounds, large amounts of tributyltin(TBT) and triphenyltin(TPT) have been used as antifouling agents because they have a superior ability to prevent marine organism from being encrusted on ship bottoms and in culturing nets. Environmental pollution by these organotin compounds in the aquatic environment were undertaken. The international maritime Organization's established a provisional tolerable daily intake(TDI) of 1.6[micro]g TBTO/kg/ B.W. The Food and Agiculture Organization (of the United Nations)/world Health Organization's (FAO/WHO) proposed a TDI of 0.5ug TPT/kg BW/d. This study is conducted monitoring of TBT on seafoods in Korea and risk assessment for exposure on TBT in seafoods. Total hazard index(using Reference Dose : 0.3 ug TBTO/kg B.W/day) of intake exposure on seafoods is 0.04 as the 50th percentile, 0.08 as the 95th percentile. This value is estimated by Monte-Carlo simulation using Crystal Ball(Decisioneering Co., 2001).

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.452-460
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• 2017

Rice fields are important stopover sites for the conservation of shorebirds during long-distance migration. These fields serve as food sources providing energy for the next leg of the journey. Shorebirds are able to change their preferred food source at stopover sites. However, the type and distribution of food resources remain unknown for the shorebirds in the Republic of Korea. Therefore, we studied the type and distribution pattern of food resource (macroinvertebrates, remaining rice, and other seeds) for shorebirds in the rice fields. We have identified potential and actual food sources for shorebirds in the rice fields. The potential food sources were collected by using a core-sampling method and the actual food source was ascertained by observational analysis. As a result, a total 19 species of benthic macroinvertebrates in 15 families were recorded as potential food sources. A total of 9 families in 9 orders of benthic macroinvertebrates known to be actual food sources were also recorded during the study period, including loaches, and a tuber of sea club rush. Also, the distribution of the food source depended on soil conditions generated by cultivation such as plowing, harrowing, and the use of pesticides. In the present study, we identified the type and distribution of food sources for shorebirds. This information can be used as essential primary baseline data for conservation of shorebirds using the rice fields of the Republic of Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.3
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• pp.202-212
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• 2021

Objectives: The reproductive health of female workers has been extensively investigated in South Korea and other countries worldwide. However, few studies have discussed the reproductive health of male workers. In this study, we reviewed the recent literature that reports on the effects of occupational exposure on the reproductive health of male workers and the health of their children. Methods: In May 2020 we used the PubMed search engine to search the literature over the last 10 years and chose case-control, cohort, and cross-sectional studies and reviews. We selected epidemiological studies that investigated the association between pre-pregnant occupational exposure and the reproductive health of male workers and the health of their children. We excluded case reports, non-epidemiological studies (animal experiments, cellular-level experiments, and similar articles), and studies that described postnatal occupational exposure. Results: We eventually selected 23 studies. The studies that included exclusively male workers reported that those employed in the agricultural sector or those exposed to pesticides showed lower blood levels of reproductive hormones and a high risk of lympho-hematopoietic system cancer in their children. Male workers exposed to complex organic solvents and organic compounds showed a high risk of poor semen quality, increased time to pregnancy, decreased blood levels of reproductive hormones, and a high risk of lympho-hematopoietic system cancer in their children. Male workers employed in occupations that involved significant social contact, or in the leather and livestock industries, and in occupations with high levels of exposure to lead and organic solvents showed a high risk of malignancies, including lympho-hematopoietic system cancer, neuroblastoma, and central nervous system tumors in their children. Studies that investigated both male and female workers reported that children of male smelters showed a high risk of premature birth, and children of male workers exposed to metals showed a high risk of hypospadias and cryptorchidism. Children of male welders and workers employed in the glass, ceramic, and tile industries showed a high risk of premature birth. Conclusion: The findings of this study will serve as basic data for further research on male workers' reproductive health and provide a scientific basis for the development of strategies to protect the reproductive health of males employed in high-risk occupations. Moreover, the results of this study may provide guidelines to improve the understanding of and knowledge on male workers' reproductive health.

• Journal of agricultural medicine and community health
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• v.48 no.3
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• pp.178-188
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• 2023

Objective: Self perceived health status dose not only reflects an individual's perception of their overall well-being but is also known to be influenced by various aspects of life. Rural areas tend to have relatively lower quality of life compared to urban areas. Therefore, this study aims to investigate factors related to Self perceived health status among farmers. Methods: In the subjective health status questionnaire, responses of "very healthy" and "healthy" are classified as 'good', whereas "average", "unhealthy" or "very unhealthy" are classified as indicative of a 'poor' subjective health status. Logistic regression analysis was conducted to calculate odds ratios(OR), aiming to investigate factors related to self perceived health status. Results: The OR for self perceived health status as poor was statistically significant for females at 2.32(95% CI 1.47-3.67), for individuals working in greenhouses at 1.43(95% CI 1.01-1.98), for current smoker at 1.50(95% CI 1.02-2.08), and for those who experienced symptoms after pesticide exposure at 1.74(95% CI 1.13-2.67). An annual income of 50 million won or more had a statistically significant OR of 0.51(95% CI 0.28-0.91), education level of high school and above had an OR of 0.45(95% CI 0.32-0.63), and engaging in physical exercise had an OR of 0.61(95% CI 0.42-0.89). Conclusions: The factors related to self perceived health status were identified as sex, smoking, cultivation type, presence of symptoms after pesticide exposure, annual income, education level, and exercise status. The significance of this study lies in providing foundational data for the development of health management programs for farmers.

• Korean journal of applied entomology
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• v.62 no.4
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• pp.355-363
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• 2023

In addition to causing direct feeding damage to a variety of greenhouse crops, Frankliniella occidentalis also inflicts indirect harm by facilitating the transmission of the tomato spotted wilt virus. Historically, the prevention of F. occidentalis infestations has relied heavily on pesticide use. However, this approach has led to significant side effects in agricultural ecosystems, including the development of pest resistance and challenges in effective prevention. In response to these issues, research has been directed towards identifying alternative substances that circumvent the tolerance developed against chemical pesticides. Extracts from sixty-seven medicinal plants were prepared by soaking them in water for 24 hours at room temperature. These extracts were then applied to adult F. occidentalis, with particular attention to moutan extract treatment. This treatment demonstrated a 100% insecticidal effect on the first day. The moutan extract, specifically, was prepared using 50% ethanol, after which the ethanol and water were removed via a rotary evaporator. The resultant product was then lyophilized into a powder and used after being diluted with water. In indoor experiments, a 40% diluted solution was sprayed onto F. occidentalis, exhibiting a 100% insecticidal effect 24 hours post-treatment. Furthermore, a pot test indicated a 78% insecticidal effect on the first day of application. Ongoing research includes the analysis of active substances that demonstrate exceptional insecticidal properties and the conduct of on-site validation tests. The application of the aforementioned extract is anticipated to be effective in the prevention of F. occidentalis infestations.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.306-315
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• 1987

In the red pepper field under polythylene film mulching(P.E.-mulching) culture, the weed emergence was completely inhibited by black P.E.-mulching. The emergence in clear P.E.-mulching decreased 90% compared to that in non-mulching. Weeding effect was high in the order of pendimethalin, diphenamid, alachlor and napropamide. The effect of herbicides was higher in clear P.E.-mulching than in non-mulching. Plant height and number of branches increased in the order of clear P.E.-, black P.E.-mulching, while the yield between black P.E.- and clear P.E.-mulching was not different. The herbicides had no effect on the growth and yield. In the peanut field, weed emergence was 80% lower in clear P.E.-mulching than in non-mulching. Weeding effect was excellent in the plot applied with alachlor, napropamide and diphenamid. The total number of branches, main stem height and shoot weight were 2.0, 1.7 and 2.4 times greater in clear P.E.-mulching than in non-mulching, respectively. Peanut yield was about 38% higher under clear P.E.-mulching than under non-mulching. The herbicides had no effect on the growth and yield. In the sesame field, rate of weed emergence was 10 times lower in clear P.E.-mulching than in non-mulching. Weeding effect of alachlor, napropamide and diphenamid was higher under clear P.E.-mulching than under non-mulching. Germination percentage of sesame greatly decreased in non-mulching compared with in clear P.E.-mulching. The germination was inhibited by the treatment of herbicides. The inhibition effect was increased in the order of alachlor, napropamide, and diphenamid. The initial crop injury in treatment of herbicides was greater in non-mulching than in clear P.E.-mulching. The crop recovered from the injury and exhibited regrowth in clear P.E.-mulching except the alachlor treatment, but there was no recovery in non-mulching. There was no significant difference yield between herbicide treatment and hand weeding in non-mulching. Also, no significant difference was obseorbed between napropamide and diphenamid treatment and hand weeding in clear P.E.-mulching.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.264-270
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• 2013

Imidacloprid is a systemic insecticide which act as an insect neurotoxin. It used for control of pest such as aphids and other sucking insects in fruits and vegetables. Systemic pesticides move inside a crop following absorption by the plant, and these were converted into a variety of metabolites. Sometimes these metabolites make a problem about safety of agricultural products. So a simultaneous determination method of pesticide and its metabolites is needed, to monitor their presence in agricultural product and study on the fate of pesticide in a plant. This study's aim is to investigate simultaneous analysis method of imidacloprid and its metabolites, imidacloprid guanidine, imidacloprid olefin, imidacloprid urea, and 6-chloronicotinic acid in red pepper using QuEChERS method and LC-MS/MS systems. QuEChERS method was modifed beacuase $MgSO_4$ salts decreased the recoveries of 6-chloronicotinic acid in extraction procedure. Imidacloprid and its metabolites were extracted by acetonitrile with 1% glacial acetic acid and the extracts were purified through QuEChERS with primary secondary amine (PSA) and $C_{18}$ and analyzed with LC-MS/MS in ESI positive mode. Standard calibration curves were made by matrix matched standards and their correlation coefficients were higher than 0.999. Recovery studies were carried out on spiked pepper blank sample at four concentration levels (0.01, 0.04 and 0.1, 0.4 mg/kg). The average recoveries of imidacloprid and its metabolites were in the range of 70~120% with < 20% RSD. This result indicated that the method using QuEChERS and LC-MS/MS was suitable for the simultaneous determination of imidacloprid and its metabolites in red pepper.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.307-313
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• 2013

This study was carried out to investigate the residual characteristics of fungicide azoxystrobin and difenoconazole in Prunus mume fruits, and establish pre-harvest residue limits (PHRL) based on dissipation and biological half-lives of fungicide residues. The fungicides were sprayed onto the crop at recommended dosage once and 3 times in 7 days interval, respectively. The samples were harvested at 0, 1, 2, 4, 6, 8, 10, 12 and 14 days after treatment. These residual pesticides were extracted with QuEChERS method, clean-up with $NH_2$ SPE cartridge, and residues were analyzed by HPLC/DAD and GLC/ECD, respectively. Method quantitative limits (MQL) of azoxystrobin were 0.03 mg $kg^{-1}$ and of difenoconazole were 0.006 mg $kg^{-1}$. Average recovery were $93.2{\pm}2.49%$, $85.5{\pm}1.97%$ for azoxystrobin at fortification levels at 0.3 and 1.5 mg $kg^{-1}$, and $100.8{\pm}6.74%$, $87.6{\pm}9.92%$ for difenoconazole at fortification levels at 0.06 and 0.3 mg $kg^{-1}$, respectively. The biological half-lives of azoxystrobin were 5.9 and 5.2 days at recommended dosage once and 3 times in 7 days interval, respectively. The biological half-lives of difenoconazole were 9.3 and 8.0 days at recommended dosage once and 3 times in 7 days interval, respectively. The PHRL of azoxystrobin and difenoconazole were recommended as 5.32 and 1.64 mg $kg^{-1}$ for 10 days before harvest, respectively.