• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.99-106
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• 1998

This study was performed to investigate the bioconcentration of dichlorvos, methidathion and phosalone in zebrafish (brachydanio rerio), red sword tail(Xiphophorus hellieri). The fishes were exposed to 0.05 ppm, 0.01 ppm, 0.50 ppm, one-hundredth concentration of 96-hrs LC$_{50}$ and one-thousandth concentration of 96-hrs LC$_{50}$ and test periods were 3, 5 and 8 days. The deputation rate of each pesticide from the whole body of fish was determined over the 24-hr period after treatment. Obtained results are summerized as follows: In the case of dichlorvos, dichlorvos concentration in zebrafish extract and BCF$_{s}$ of dichlorvos were increased as increasing test concentration. In the case of same experimental concentrations, dichlorvos concentration in zebrafish extract and BCF$_{s}$ of dichlorvos were decreased as proloning test periods, especially dropped after 5days. Dichlorvos concentration in red sword tail extract were increased as increasing test concentration, lyat BCF$_{s}$ in concentration of 0.05 ppm, 0.01 ppm and one-hundredth of 96-hrs LC$_{50}$ were decreased. Methidathion and phosalone concentration in zebrafish extract in zebrafish extract were increased as increasing test concentration, but there was little difference in BCF$_{s}$. In the case of same experimental concentrations, there were little differences in BCF$_{s}$ and concentration in zebrafish extract. In the case of red sword tail, it was impossible to calculate on BCF$_{s}$ data because test concentration was under the detecting limit on GC or test fish were die. Determined deputation rate conatant were highest on dichlorvos, and followed by methidathion, and phosalone. The results of determining depuration rate of these pesticides showed that the high BCF in fish might be due to the slow depuration rate in fish, it is thought to be responsible for vapor pressure, water solubility and partition coefficient. It is suggested that one-hundredth concentration of 96-hrs LC$_{50}$ will be proper test concentration because one-thousundth of LC$_{50}$ was under the detecting limit on GC. Dichlorvos, methidathion and phosalone, organophosphorous pesticides, were examined to their BCF$_{s}$ and depuration rates by means of fish test.

• 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 Food Hygiene and Safety
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• v.14 no.4
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• pp.339-345
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• 1999

The present study was performed to investigate photodegradation rate constants and degradation products of dichlorvos and methidathion by the USEPA method. The two pesticides were very stable in sunlight for 16 days from September 2 to 18, 1998 and humic acid had no sensitizing effect on the photolysis of each pesticide in sunlight. The photolysis rate was fast-est for methidathion, followed by dichlorvos in the presence of UV irradiation. Photodegradation rate constant and half-life of dichlorvos were 0.0208 and 33.3 min, respectively. Photodegradation rate constant and half-life of methidathion were 0.6789 and 1.0min, respectively. The two pesticides were degraded completely in the presence of UV irradiation and UV irradiation with TiO$_2$in about 3 hours. Therefore, it is suggested that UV treatment will be effective for the degradation of pesticides in the process of drinking water purification. In case of dichlorvos and methidathion, UV irradiation with TiO$_2$was more effective for degradation than W irradiation. In order to identify photolysis products, the extracts of degradation products were analyzed by GC/ MS. The mass spectrum of photolysis products of dichlorvos was at m/z 153, those of the photolysis of methidathion were at m/z 198 and 214, respectively. Photolysis products of dichlorvos was Ο, Ο-dimethyl phosphate(DMP), those of methidathion were Ο, Ο-dimethyl phosphorothioate(DMTP) and Ο, Ο-dimethyl phosphorodithioate (DMDTP).

• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.465-474
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• 1986

The solvent extraction and cleanup processes for the simultaneous gas-liquid chromatographic determination of 11 kinds of organophosphorous pesticide residues in crops were investigated. The extracts dissolved with acetone were partitioned with petroleum ether after adding saturated NaCl solution. Evaporated the partitioning solvent, the residue was dissolved in methylene chloride and eluted through mixed adsorbent (1 : 2 : 4 of activated carbon, magnesia and diatomaceous earth) with methylene chloride as an eluent. The pesticides recovered were 82∼105% and the impurities were effectively removed.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.318-326
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• 2007

Characteristics of organophoshhorus pesticides (OPs) distribution were investigated in Shingu Reservoir, as a shallow eutrophic agriculture reservoir in Korea. In August 2006, IBP, DDVP and dyfonate were detected in the water column of Singu Reservoir, ranging from 1340.7 to 16030.1 ng $L^{-1}$, 58.7 to 127.6 ng $L^{-1}$ and N.D. to 20.3 ng $L^{-1}$, respectively, However, in September 2006, mevinfos, ethoprofos, phorate, chlorfenvinfos, and methidathion were also found in addition to IBP (202.5${\sim}$213.2 ng $L^{-1}$), DDVP (100.7${\sim}$340.6 ng $L^{-1}$) and dyfonate (N.D.${\sim}$25.0 ng $L^{-1})$. Maximum concentrations of OPs were observed at the middle depth in August, which might be related with photo-oxidation. On the other hand, IBP and DDVP among the OPs were detected in suspended particles, suggesting the relatively active adsorption reactivity. The composition of OPs varied temporally on account of the influence of inflow water from its surrounding areas. In the present study, the observed OPs concentrations seem to be not acute toBic levels to aquatic organisms in Shingu Reservoir, considering the standard monitoring levels of U.S. Environmental Protection Agency and Japan Ministry of Environment.

• Journal of Preventive Medicine and Public Health
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• v.26 no.2 s.42
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• pp.268-281
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• 1993

The aquatic quality of the Naktong river after two or three months in June, 1991 with phenol spillage from a electrical factory in Kumi was investigated. The samples were collected at six sites of the Naktong river basin and Kachang and Kongsan lakes. Phenol was not detected from all water samples. Turbidity was very much increased to the down stream in the Naktong river. The BOD and COD values exceeded the 2nd grade(3mg/l) of the Korean standard quality of Environmenal Water Act at the all sampling sites of the Naktong river. Especially, the value of COD at Kaejin (12.5mg/l) was poorly classified as to the 5th grade of water class for the environmental quality standards. Organophosphorous pesticides such as parathion, malathion, fenitrothion and diazinon were investigated but not detected. Diazinon was only detected at the Ilsan bridge(1.42ppb), Okkye stream(6.95ppb), Waekwan bridge(0.32ppb), Gangjung reservior(0.13ppb), Kaejin (0.05ppb). Of the carbamates such as carbanyl, isoprocarb and cabofuran, the carbofuran was detected all sites except tap water, and Kachang and Kongsan lakes. The content of heavy metals such as Cd, Pb, Zn, Fe, Mn, Hg were not exceeding for drinking water standards at the all sampling region, but only mecury was detected from Okkye stream(0.018ppb) and Kaejin (0.09ppb). In the regions of Kachang and Kongsan lakes, the content of heavy meatals were lower than that of reservior of Naktong river.

• Journal of agricultural medicine and community health
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• v.8 no.1
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• pp.19-27
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• 1983

This study was carried out to obtain the basic data for the prevention of chronic poisoning by organic phosphorous pesticides and to estimate the normal range of plasma cholinesterase activity level for Korean agricultural workers. The 285 agricultural workers were randomly selected for the study in Jungup Gun, Jeonbug Province, 135 persons of them were tested in the period of pre-exposure of organophosphorous pesticides (April 1981) and rest of them were tested after exposure(August 1981). Cholinesterase activity levels were measured by the Micro-method of Takahashi Hiroshi. Major findings are as following: 1) There is significant difference in plasma cholinesterase activity levels between the pro-exposed and post exposed group(p > 0.01). Mean values of plasma cholinesterase activity levels were $7.60{\pm}1.74{\mu}M/20{\mu}{\ell}$/hr. in the pre-exposed group and $6.23{\pm}1.59{\mu}M/20{\mu}{\ell}$/hr. in the post-exposed group. 2) Plasma cholinesterase activity in Korean agricultural worker could be estimated $7.30-7.90{\mu}M/20{\mu}{\ell}$/hr. with 95% confidence interval.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.396-401
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• 2010

Tolclofos-methyl is one of the most widely used organophosphorous pesticides in control of soil-borne diseases in ginseng field. In Korea, residues of tolclofosmethyl in ginseng and cultivation soil is quite often detecting. The objective of this study was to know the possibility for the accelerated degradation of tolclofos-methyl by various chemical treatment under soil slurry condition. The degradation of tolclofos-methyl was accelerated by zerovalent metals treatment in soil slurry. The degradation rate of tolclofos-methyl was found to be at higher zerovalent zinc than unannealed zerovalent and annealed zerovalent iron. The effect of different sizes of zerovalent iron on tolclofos-methyl degradation was showed that the smaller size of zerovalent iron, the greater the degradation rate. In aqueous solution of pH 4.0 below the degradation rate of tolclofos-methyl was very high. Under this experimental condition, tolclofos-methyl degradation was the greatest at 2% (w/v) of ZVI under 0.1 N of HCl in 24 hours, the degradation rate was 94.4%. By testing various chemicals, it was found that $Fe_2(SO_4)_3$ as iron source showed better for degrading tolclofos-methyl in $H_2O_2$ 500 mM treatment and sodium sulfite also showed the degradable possibility tolclofos-methyl in soil slurry.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.148-155
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• 2014

The transfer pattern of chlorpyrifos present in soil to cucumber plants were assessed and reported with plant growth, concentration dependency, and duration. Cucumber seedlings cultivated in a growth chamber for 30 days and a greenhouse for 120 days. Weight and length of cucumbers cultivated in the chamber increased with the increasing time, while the uptake of chlorpyrifos by cucumber increased a period from 0 to 15 days and decreased after 15 days. Uptake rates of chlorpyrifos into a cucumber plant were 1.0~1.3% to initial amounts treated with 20 and 40 mg/kg to soil. Most chlorpyrifos residues were detected in root, followed by stem and leaf. Results of the greenhouse test showed that chlorpyrifos amounts in cucumber fruits were present less than LOQ (0.02 mg/kg), and chlorpyrifos was mainly found in the root of the cucumber plant. Chlorpyrifos absorbed in a cucumber under greenhouse condition was smaller than that in chamber condition as 0.03~0.04%. Degradation patterns of chlorpyrifos in soils were similar during indoor and outdoor tests with half-lives of 25.8~73.0 days. These results may be useful for establishing the management strategy of residual pesticides in soil environment.