• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.12-18
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• 2001

The effects of organophosphorus were examined with inhibition of the cholinesterase activity on tile chicken plasma in vivo and in vitro. The cholinesterase activity in chicken plasma determined by tile Ellman mettled was $23{\mu}mol$/min/g protein. After oral administration with 0.2 and 0.5 times of organophosphorus terbufos $LD_{50}$(1.81 mg/kg), cholinesterase activity were inhibited to 36% and 96% of control after 15min in vivo, respectively. After oral administration with 0.2 and 0.5 times of terbufos $LD_{50}$(1.81 mg/kg), then the recovery of cholinesterase activity followed to 99% and 56% of control after 11hr, respectively. Ki of phosphorodithioate and phosphorothioate with P=S was $74{\sim}322\;mole^{-1}min^{-1}$ in vitro. Ki of phosphate and phosphorothiolate with P=O was $13898{\sim}79610\;mole^{-1}min^{-1}$. Toxicology of organophosphorus with P=S was higher than that of organophosphorus with P=S by oxidation. $pI_{50}$ of phosphorodithioate and phosphorothioate with P=S was $21{\sim}102$ mg/L. $pI_{50}$ of phosphate and phosphorothiolate with P=O was $0.519{\sim}0.071$ mg/L. Enzyme-Inhibition method with cholinesterase was the rapid bioassay method to detect the organohpophorus pesticides in vitro.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.144-153
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• 2007

One of the most recent issues facing the pesticides regulatory process is the assessment of the potential for pesticides to leach through soil and appear in groundwater. Since Jeju island depends on a hydrogeologically vulnerable aquifer system as its principle source of drinking water, it is important to identify which pesticides are the most likely to result in groundwater contamination. The objective of this study was to assess groundwater contamination risk of 21 pesticides (12 insecticides, 6 herbicides and 3 fungicides) in Jeju soils using groundwater ubiquity score (GUS). Considering GUS estimated in 21 representative series of Jeju soils, generally herbicides showed relatively higher leaching potentials and insecticides showed lower leaching potentials. Groundwater contamination risk was higher in the order of bromacil > metolachlor > alachlor > linuron pretilachlor > butachlor for herbicides, carbofuran > ethoprophos > diazinone > dimethoate > penthoate > mecarbam > methidathion > endosulfan > fenitrothion > parathion > chlorpyrifos > terbufos for insecticides, and metalaxyl > chlorothalonil > triadimefon for fungicides. Among the tested pesticides alachlor, metolachlor, bromacil, ethoprophos and carbofuran were classified as the pesticides of very high or high groundwater contamination potential. Although the ranking of the leaching potential was essentially determined on the base of the intrinsic properties of the chemicals and environmental properties, variation of the relative groundwater contamination potentials of each pesticides in different soils were not significant. Therefore, the above ranking of groundwater contamination risk would be applied in most of Jeju soils. To lower the possibility of pesticide contamination of groundwater, the use of those pesticides classified as high or very high leaching potential should be strictly regulated in Jeju Island.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1569-1582
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• 2015

The analytical method for 16 organophosphorus pesticides was developed in this study. The 16 organophosphorus pesticides were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) using on-line solid phase extraction (on-line SPE) with PLRP- S cartridge. Analysis of all analytes in the MS/MS was processed in the electrospray ioni-zation (ESI) positive mode. They are Azinphos ethyl, Chlorfenvinphos, Ethion, Famphur, Phosmet, Phosphamidon, Terbufos, Aspon, Chlorpyrifos-methyl, Crotoxyphos, Dichlofenthi-on, Dicrotophos, Fonofos, Thionazin, Dimethoate and Iprobenfos. Limits of detection (LODs) and Limits of quantification(LOQs) were obtained as 0.8~2.0 ng/L and 2.6~6.4 ng/L, respectively. All compounds were not detected at the 8 sampling points of the raw water and clean water.

• Environmental Analysis Health and Toxicology
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• v.20 no.4 s.51
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• pp.297-302
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• 2005

The purpose of this study was to provide the standard method for the analysis of organophosphorous pesticides such as chlorpyrifos, diazinon, malathion and parathion in blood. We performed method validation for these pesticides in blood according to EURACHEM (A focus For Analytical Chemistry in Europe) guide. For the analysis of the pesticides, we used solid-phase extraction ,column (Waters Oasis $HLB^{(R)}$. After the extraction, the supernatants were evaporated to dryness under the nitrogen stream. They were analyzed by gas chromatography/mass spectrometry (GC/MS) after reconstituting with ethanol. Terbufos was used as an internal standard. To validate this method, we performed verification procedures with the following parameters: selectivity, linearity of calibration, accuracy, precision, limit of detection and quantification. Validation data according to Eurachem guide were adequate for our purpose for the analysis of chlorpyrifos, diazinon, malathion and parathion in blood.

• YAKHAK HOEJI
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• v.54 no.6
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• pp.429-440
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• 2010

HS-SPME-GC/MS was studied and optimized for the determination of 17 orgarnophosphorous pesiticides (OPPs: chlorpyrifos, chlorpyrifos-methyl, demeton-s-methyl, diazinon, dimethoate, EPN, fenitrothion, fenthion, malathion, methidathion, monocrotophos, parathion, phenthoate, phosphamidon, sulfotep, terbufos, triazophos) in blood. Optimum SPME parameters were selected: choice of SPME fiber (85 ${\mu}m$ polyacrylate), pH effect (0.5 N HCl), salt effect ($Na_2SO_4$, 0.2 g; 20%), headspace incubation temperature ($80^{\circ}C$), headspace incubation time (1 min), headspace adsorption time (30 min) and GC desorption time (2 min). These parameters were optimized using HS-SPME autosampler coupled with gas chromatography-mass spectrometry (GC-MS). Method validation was carried out in terms of linearity, limit of detection (LOD), limit of quantitation (LOQ) and recovery in blood. The assay was linear over 0.5~5.0 mg/l ($r^2$=0.955~1.000). Limit of detection (LOD) and limit of quantitation (LOQ) in blood were determined 0.03~0.3 mg/l (S/N=3) and 0.1~1.1 mg/l (S/N=10), respectively. Relative recovery with 0.5, 1 and 5 mg/l (in blood) were 90.8%, 98.5% and 94.1%, respectively. This method will be applied to the determination of the orgarnophosphorous pesticides in postmortem blood. The proposed protocol can be an attractive alternative to be used in routine toxicological analysis.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.700-707
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• 2020

The root-knot nematode (Meloidogyne incognita) is an important pathogen in crop cultivation, however, few methods are available to control this parasitic roundworm. In this study, the nematicidal effects of approximately 30 Streptomyces strains isolated from soil samples of Mt. Naejang (Korea) were tested against Meloidogyne incognita, and the culture broth of the strains KRA-24 and KRA-28 exhibited approximately 75% and 85% insecticidal activity, respectively, in in vitro assays. In in vivo pot experiments, these strains reduced the number of nematodes in the soil and the number of egg masses in the roots of red peppers. The two strains also survived in the presence of insecticidal agents (0.1 to 3.0%) such as fosthiazate, ethoprophos and terbufos when they were used in parallel. The mixture of KRA-24 or KRA-28 culture broth and fosthiazate exhibited nematicidal effects that were similar to those observed when KRA-24 or KRA-28 were used alone. Our results clearly suggest that the Streptomyces strains KRA-24 and KRA-28 should be promoted as a biocontrol agent against Meloidogyne incognita.

• Korean Journal of Veterinary Research
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• v.63 no.3
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• pp.21.1-21.6
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• 2023

The increasing prevalence of toxic substance-exposure in pets in South Korea endangers the health and safety of numerous companion animals, and has become a cause for concern. Notably, the annual incidence of forensic analysis in pets has increased by more than 150% in South Korea, mainly in populous regions such as Seoul, Incheon, and Gyeonggi. In response to this growing issue, veterinary forensic examinations were conducted on 549 dogs and cats from 2019 to 2022. This study revealed the presence of various toxic substances, including pesticides, insecticides, and drugs such as analgesics, anesthetics, antidepressants, and muscle relaxants, in pets. Among the 38 different toxins identified in pets, coumatetralyl, methomyl, terbufos, and buprofezin were the most frequently detected. In this study, toxic substances for pets were identified based on the "toxic agent list for humans," developed by the National Forensic Services, because no list of toxic agents for animals currently exists and data regarding potentially toxic substances for dogs and cats is limited. This is one of the limitations of this study, and necessitates the establishment of a toxic agent list for animals. Continued monitoring and research is also recommended to reveal the incidence, causes, and solutions of toxicity in animals.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.239-249
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• 2024

In this study, we investigated the concentrations of pesticide residues in agricultural products marketed in northern Seoul and assessed their potential health risks. A total of 1,737 samples were collected using the QuEChERS method, followed by LC-MS/MS and GC-MS/MS. Pesticide residues below the MRLs were detected in 560 samples of 72 items (32.2%), but 38 samples of 22 items had pesticide residues above the MRLs. Residual pesticides were detected in 53.8% of fruits, 33.0% of vegetables, 28.6% of herbs, 15.4% of beans, and 10.5% of rice samples. Most of the samples that exceeded the MRLs were vegetables, especially leafy, stalk, stem, and root vegetables; herbs and mushrooms also exceeded the permitted MRLs. Of the 105 pesticides investigated, dinotefuran, fluxametamide, chlorfenapyr, azoxystrobin, and carbendazim were the most frequently detected, whereas 23 pesticide residues, including terbufos, carbendazim, and fluxametamide, were detected above the MRL values. The hazard indices were calculated as 0.00003-1.31406%, which suggests that the investigated pesticide residues in the samples were within safe levels, but continuous monitoring of pesticides in agricultural products is needed to ensure the safety of consumers.