• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.32-39
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• 1998

This study was performed to develop jumbo granules floated and spreaded on the water surface after application, having low production and formulation cost, and safe to environment for paddy herbicides and to establish the formulation recipe. The jumbo granules of azimsulfuron with molinate(0.075+7.5%) was formulated by KCl as water soluble carrier and paraffin oil as solvent to impose the floating and spreading force to granules. That showed 100% of total granules to be floated on and spreaded upto the water surface within 25 minutes after application. Change in carriers, surfactants and pH did not affected to improve the time-course degradation of azimsulfuron in jumbo granules, but salt formation of azimsulfuron added by 1.15M solution of NaOH a little. Addition of N-methyl acrylate and modification of formulation process affected decrease in degradation of azimsulfuron upto 1.2, 2.1, and 7.2% after 2, 6 and 12 weeks under storage at $40{\pm}2^{\circ}C$, respectively, which showed the establishment of formulation recipe of the jumbo granules.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.87-94
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• 2007

Pyrethroid insecticide have widely been used for agricultural sector and residential environments. To assess the exposure of insecticide which is absorbed through skin the analysis of urinary metabolite is essential. At present, the urinary 3-PBA was analyzed using liquid-phase extraction. But LPE have many limitations, such as long pre-treatment time and low recovery. So, this study was conducted to determine the optimum conditions for analysing 3-PBA in urine using solid phase extraction. Furthermore, this study intend to investigate the relation of concentrations of pyrethroid, deltamethrin in air and 3-PBA in urine. The optimum condition for hydrolysis was found to be done with hydrochloric acid for one hour. The recovery rates of 3-PBA were $84.6%{\pm}1.2%$, $54.8{\pm}0.9%$, $99.8{\pm}1.2%$ with XAD-2, XAD-7, XAD-16 using as the aborbents and acetone as eluents respectively. But acetonitrle and methanol gave low recovery rate and methyl cellosolve could not elute the compound. The amount of acetone for elution were 6mL, 9mL, 3mL for XAD-2, XAD-7, XAD-16 as absorbents respectively. The non-absorbed rates was $0.8{\pm}0.5%$, and $0.7{\pm}0.3%$ under XAD-16, mesh size 140-200, amount of resin 1.4g and the flow rate of eluent was 0.1mL/min. In the concentration process, we obtained 11 times higher concentration of material. The amounts of urinary 3-PBA were. The LODs of 3-PBA and deltamethrin were 0.004 mg/L, 0.038 mg/L, respectively. The further research of minute monitoring which include spray pattern, environmental condition is needed And more research about the relation between total pyrethroid exposure and urinary various metabolite are also necessary.

• Korean Journal of Environmental Agriculture
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• v.12 no.3
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• pp.209-218
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• 1993

The behaviour of insectcide ethoprophos (O-ethyl S,S-propyl phosphorodithioate) in soil was investigated. In a laboratory study, the degradation of ethoprophos in soil followed first-order reaction kinetics. The half-life of the insecticide in the soil incubated with 10, 18 and $25^{\circ}C$ was 12.4, 5.5 and 2.5 days, respectively. Arrhenius activation energy was 73.8 KJ/mole. The half-life was 46.4, 17.6 and 6.9 day in the soil with 7, 14 and 19% of soil water content, respectively. The moisture dependence B value in empirical equation was 1.67. The adsorption isotherm for ethoprophos in the soil agreed with freundlich equation. The adsorption distribution coefficient (Kd) was 0.27. In a field study prepared in autumn with undisturbed soil column in a mini-lysimeter system, ethoprophos residues were largely distributed in the top $0{\sim}2cm$ soil layer and moved down to the top 6cm soil layer. Persistence of ethoprophos in field soil was correlated with variation in weather pattern during the period of experiments. The half-life of ethoprophos treated at March and October was about 17 and 5 days, respectively. The ethoprophos woil was degraded up to 90% at 37day after the both treatment. In persistence and mobility of ethoprophos in field soil, the observed data were reasonably corresponded with predicted data by some computer model of pesticide behaviour.

• Journal of Environmental Science International
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• v.27 no.7
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• pp.561-575
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• 2018

Agricultural soils around springwaters heavily affected by pesticide run-off and around wells considering the regional characteristics were collected at 24 stations in Jeju Island, and the physicochemical properties and adsorption and leaching characteristics of four nonionic pesticides (diazinon, fenitrothion, alachlor, and metalaxyl) were investigated. The values of the major soil factors affecting the adsorption and leaching of pesticides, namely, soil pH($H_2O$), organic matter content, and cation exchange capacity (CEC), were in the range of 4.64 ~ 8.30, 0.9 ~ 13.1% and 12.7 ~ 31.7 meq/100 g, respectively. The Freundlich constant, $K_F$ value, which gives a measure of the adsorption capacity, decreased in the order of fenitrothion > diazinon > alachlor > metalaxyl, which was identical to their lower water solubility. Among the collected soils, the $K_F$ value was very highly correlated with organic matter content ($r^2=0.800{\sim}0.876$) and CEC ($r^2=0.715{\sim}0.825$) and showed a high correlation with clay content ($r^2=0.473{\sim}0.575$) and soil pH($H_2O$) ($r^2=0.401{\sim}0.452$). The leaching of pesticides in the soil column showed a reverse relationhip with their adsorption in soils, i.e., the pesticides leached more quickly for the soils with lower values of organic matter content and CEC among the soils and for the pesticides with higher water solubility.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.338-338
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• 2015

하천으로 유입되어 수질 오염을 야기하는 오염원은 오염 배출원이 명확하여 하나의 점으로 나타낼 수 있는 점오염원(Point Source)과 오염원이 명확치 않은 비점오염원(Non-point)으로 구분된다. 생활하수, 축산폐수와 같이 오염원이 명확한 점오염원은 하천 유입 이전에 처리장을 거쳐 정화작업이 가능한 반면, 비점오염원은 오염원이 명확치 않아 처리에 어려움이 따른다. 또, 오염물의 양과 이동 경로가 예측이 불가능하고 강우시에는 특별한 처리 없이 하천으로 바로 유입된다. 비점 오염원의 종류는 토사, 영양물질, 유기물질, 농약, 바이러스 등 다양하다. 이 중에서 토양에 흡착되어 이동하는 질소와 인은 하천으로 유입되어 부영양화를 야기하는 특성이 있어 더욱 처리가 필수적이다. 이러한 비점오염원으로 인한 수질 오염을 줄이기 위해 여러 최적관리기법(Best Management Practices, BMPs)이 제시되어 있으며 오염 물질의 하천 유입을 차단하는 것에 중점을 둔다. 가장 널리 이용되는 방법으로는 비점오염원 저감시설 중 하천변에 식물체를 설치하여 토양의 유실을 막는 식생대(Vegetative Filter Strip, VFS)가 있다. 식생 밀집 지역의 설치를 통해 표면 유출을 차단하고 토양 유실 감소와 수체로의 오염물질 확산을 막을 수 있다. 이에 VFSMOD-w를 이용하여 강우시 식생대를 통한 토양 유실 감소 효율에 대한 연구를 수행하였다. 연구 대상 지역으로 비교적 수문 및 토양 자료가 풍부한 청미천 유역을 선정하였다. 그 결과, 식생대의 길이와 식생대 내 식물체의 파종간격이 가장 지배적인 영향을 미치는 것이 확인된다. 이때, 식물체의 종류는 식물체 파종으로 인해 변화되는 토양의 수정된 Manning의 조도계수로 구분한다. 모든 강우 및 식물체 조건이 동일할 때, 식생대 내 식물의 파종 간격이 좁고 식생대의 길이가 길수록 토사 저감 효율이 증가하는 결과가 도출되었다. 식물체의 높이, 식물체의 종류 및 식물의 파종간격이 입력 자료로 요구되나 이 중 식물체의 높이는 토사 저감 효율에 영향을 미치지 않는 것으로 나타났다. 또, 동일한 강우 조건에서 식생대의 길이가 0.5 m에서 1.0 m로 2배 증가하였을 때 토사 저감 효율이 두 경우 모두 95% 이상의 효율을 보이는 것이 나타났다. 이는 식생대의 길이가 증가할수록 토사 저감 효율이 증가하나 일정 길이 이상이 되면 대부분의 토사가 저감되는 것을 의미한다. 결론적으로 식생의 파종 간격이 좁을수록 토사 저감 효율이 증가하더라도 식물체의 성장을 고려한 적절한 파종 간격을 선정하여야 한다. 즉, 식생대의 설치는 적절한 파종 간격 및 식생대 길이를 식생대 설치지역의 강우 특성에 따라 결정지어야 한다고 판단된다.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.19-25
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• 2000

The leaching behaviour of quinclorac was elucidated using soil columns. On top of each glass column packed with a rice paddy soil up to the 30 cm height were applied three different treatments of [$^{14}C$]quinclorac: quincloiac only (T-1), quinclorac adsorbed onto active carbon (T-2), and quinclorac adsorbed onto a mixture of active carbon and $Ca(OH)_{2}$ (T-3). Half of the columns were planted with rice plants for 17 weeks and half of them unplanted for comparison. Average amounts of $^{14}C$-activity percolated from tile soil columns without rice plants in T-1, T-2, and T-3 were 81.1%, 27.8% and 48.0%, respectively, of tile originally applied $^{14}C$, whereas those with rice plants grown were 36.8%, 9.6% and 11.0%, respectively, indicating that the leaching of [$^{14}C$]quinclorac was significantly affected by vegetation and by treatment with the adsorbents. The bioavailability of the herbicide to rice plants in T-1, T-2, and T-3 were 13.6%, 11.0% and 13.9%, respectively. The residue levels of quinclorac in the edible part of rice grains would be far less than the maximum residue limit (MRL, 0.5 ppm). After the leaching, the amounts of $^{14}C$ remaining in soil in with rice planting T-1, T-2, and T-3 were 36.3%, 73.7%, and 61.8%, whereas those without rice planting were 19.7%, 71.1%, and 52.3%, respectively. The balance sheets indicate that [$^{14}C$]quinclorac translocated to rice shoots would be lost by volatilization and/or in other ways in T-1 and T-3. The $^{14}C$-activity partitioned into the aqueous phase of the leachates collected from all treatments was less than 7% of the total, but it increased gradually with time in the case of rice growing, suggesting tile formation of some polar degradation products.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.68-74
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• 2017

An analytical method for detecting metamifop residue in paddy water, soil, and rice with high performance liquid chromatography (HPLC) was developed. Water was extracted with ethyl acetate before analyzing by HPLC. Soil residues were extracted with acetone under acidic condition and after purifying with $Extrelut^{(R)}$ NT, and silica SPE, the residue was analyzed by HPLC. For residue analysis in rice, the procedure involved extraction with acetone, purification with $Extrelut^{(R)}$ NT, partitioning between acetonitrile/hexane, purification with silica SPE cartridge, and analysis by HPLC. The limit of detection (LOD) was 1.0 ng, limit of quantitation (LOQ) was 3.0 ng, and method limit of quantitation (MLOQ) were 0.001 mg/L for paddy water, 0.01 mg/kg for rice and soil, respectively. Standard calibration curve shows linearity from 0.05 mg/kg to 5.0 mg/kg ($R^2=0.9999$). The recoveries in fortified paddy water were $91.3{\pm}3.5%$ (0.01 mg/L level) and $93.2{\pm}6.3%$ (0.05 mg/L level). The recoveries in fortified paddy soils were $92.5{\pm}4.0%$ (0.1 mg/kg level) and $92.7{\pm}4.0%$ (0.5 mg/kg level) in soil A, while, $102.3{\pm}4.4%$ (0.1 mg/kg level) and $98.9{\pm}7.9%$ (0.5 mg/kg level) in soil B, respectively. The recoveries in fortified rice were $93.0{\pm}6.9%$ (0.1 mg/kg level) and $85.0{\pm}3.5%$ (0.5 mg/kg level). This method was proved to be effective and can be used to determine the metamifop residue in paddy water, paddy soil, and rice.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.210-217
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• 2015

Ipfencarbazone is a herbicide of the tetrazolinone class, and is believed to be an inhibitor of very long chain fatty acids (VLCFAs), which control cell division in weeds. The objective of this study was to develop and validate an official analytical method for ipfencarbazone determination in agricultural products. The ipfencarbazone residues in agricultural products were extracted with acetone, partitioned with n-hexane, and then purified through silica SPE cartridge. Finally, the analyte was quantified by gas chromatograph-electron capture detector (GC-ECD) and confirmed with gas chromatograph/mass spectrometer(GC/MS). The linear range of ipfencarbazone was 0.01 to 1.0 mg/L with the coefficient of determination ($r^2$) of 0.9999. The limit of detection (LOD) and quantification (LOQ) was 0.003 and 0.01 mg/kg, respectively. In addition, average recoveries of ipfencarbazone ranged from 80.6% to 112.3% at the different concentration levels LOQ, 10LOQ and 50LOQ, while the relative standard deviation was 2.2-8.6%. All values were consistent with the criteria ranges requested in the CODEX guidelines. Furthermore, and inter-laboratory study was conducted to validate the method. This proposed method for determination of ipfencarbazone residues in agricultural products can be used as an official analytical method.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.95-103
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• 2010

Fomesafen is a selective herbicide, and used to control annual and perennial broad-leaf grass on soybean and fruit fields in USA and China, but not introduced in Korea yet. So, MRL (Maximum Residue Level), and analytical method of fomesafen were not establishment in Korea. Therefore, this experiment was conducted to establish a determination method for fomesafen residue in crops using HPLC-UVD/MS. Fomesafen residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and dichloromethane partition was followed to recover fomesafen from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The fomesafen was quantitated by HPLC with UVD, using a Shiseido CAPCELL-PAK UG C18 column. The crops were fortified with fomesafen at 3 levels per crop. Mean recovery ratio were ranged from 87.5% for a 0.4 ppm in hulled rice to 102.5% for a 0.4 ppm in apple. The coefficients of variation were ranged from 0.6% for a 2.0 ppm in hulled rice to 7.7% for a 0.04 ppm in green pepper. Quantitative limit of fomesafen was 0.04 mg/kg in representative 5 crop samples. A LC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of fomesafen in agricultural commodities.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.104-116
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• 2018

BACKGROUND: This experiment was conducted to establish a simultaneous analysis method for 7 kinds of herbicides in 3 different classes having similar physicochemical property as diphenyl ether(bifenox and oxyfluorfen), dinitroaniline (ethalfluralin and trifluralin), and chloroacetamide (metolachlor, pretilachlor, and thenylchlor) in crops using GC-ECD/MS. METHODS AND RESULTS: All the 7 pesticide residues were extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice and soybean. The extract was diluted with saline water and directly partitioned into n-hexane/dichloromethane(80/20, v/v) to remove polar co-extractives in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. The analytes were separated and quantitated by GLC with ECD using a DB-1 capillary column. Accuracy and precision of the proposed method was validated by the recovery experiment on every crop samples fortified with bifenox, ethalfluralin, metolachlor, oxyfluorfen, pretilachlor, thenylchlor, and trifluralin at 3 concentration levels per crop in each triplication. CONCLUSION: Mean recoveries of the 7 pesticide residues ranged from 75.7 to 114.8% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of the analytes were 0.004 (etahlfluralin and trifluralin), 0.008 (metolachlor and pretilachlor), 0.006 (thenylchlor), 0.002 (oxyfluorfen), and 0.02 (bifenox) mg/kg as verified by the recovery experiment. A confirmatory technique using GC/MS with selected-ion monitoring was also provided to clearly identify the suspected residues. Therefore, this analytical method was reproducible and sensitive enough to determine the residues of bifenox, ethalfluralin, metolachlor, oxyfluorfen, pretilachlor, thenylchlor, and trifluralin in agricultural commodities.