• Analytical Science and Technology
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• v.10 no.3
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• pp.168-178
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• 1997

The optimum conditions for the residual analysis of the ethalfluralin herbicide on soils were investigated and the residues in soils were determined by gas chromatography with electron capture detector(GC-ECD). The soil samples extracted with methanol and dichloromethane and concentrated. The concentrated phase were redissolved with toluene and analyzed with GC-ECD after separated by cyanosilica gel Sep-Pak cartridge. From the standard addition experiments with 0.1 and 1.0ppm, the average recoveries were 92.8~101.2% and the detection limit was 0.004ppm. The half-life time of ethalfluralin in the soil(A) was 35 days in the laboratory and 7.2 days in the field test whereas it was 45 days and 9.7 days for each in case of soil(B).

• Toxicological Research
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• v.16 no.2
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• pp.173-178
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• 2000

This study was carried out to investigate cytotoxicity of several herbicides (Bentazone, Butachlor. Paraquat and Ethalfluralin) in cultured mouse NIH 3T3 fibroblasts. Tetrazolium (MTT), neutral red (NR) and sulforhodamine protein B (SRB) of the colorimetric assays were performed to evaluate the cytotoxicity on cell organelles. 2 x 10$^4$cell/$m\ell$ of NIH 3T3 fibroblast in each well of 24 multidish were cultured. After 24 hours, the cells were treated with solution (1, 25, 50 or 100 $\mu$M) of each herbicide. After the NIH 3T3 fibroblasts of all groups were cultured in the same condition for 48 hours, MTT, NR and SRB assays were performed to evaluate the cytotoxicity. The light microscopic study was carried out to examine morphological changes of cultured NIH 3T3 fibroblasts. The MTT$_{50}$ of Bentazone, Butachlor, Paraquat and Ethalfluralin were 1560.97 $\mu$M, 56.15 $\mu$M, 3138.81 $\mu$M and 1301.82 $\mu$M, respectively. The NR$_{50}$ of Bentazone, Butachlor. Paraquat and Ethalfluralin were 1763.93 $\mu$M, 45.98 $\mu$M, 1030.85 $\mu$M and 1808.29 $\mu$M, respectively. The SRB$_{50}$ of Bentazone, Butachlor. Paraquat and Ethalfluralin were 1913.38 $\mu$M, 65.30 $\mu$M, 1860.73 $\mu$M and 1086.93 $\mu$M, respectively. The morphological changes of NIH 3T3 fibroblasts showed severe degeneration in Butachlor 50 $\mu$M and 100 $\mu$M concentrations. These results indicate that Butachlor has high cytotoxicity, Bentazone, Paraquat and Ethalfluralin very weak cytotoxicity against NIH 3T3 fibroblasts.lasts.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.306-315
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• 2006

Two different experiments, adsorption/desorption and runoff by rainfall simulation of four pesticides, such as alachlor, ethalfluralin, ethoprophos and pendimethalin were undertaken their runoff and erosion losses from sloped land and to assess the influence of their properties and environmental factors on them. The mobility of four pesticides and which phase they were transported by were examined in adsorption study, and the influence of rainfall pattern and sloping degree on the pesticide losses were evaluated in simulated rainfall study. Freundlich adsorption parameters (K) by the adsorption and desorption methods were 1.2 and 2.2 for ethoprophos, 1.5 and 2.6 for alachlor, respectively. And adsorption distribution coefficients (Kd) by the adsorption and desorption methods were 56 and 94 for ethalfluralin, and 104 and 189 for pendimethalin, respectively. K or Kd values of pesticides by the desorption method which were desorbed from the soil after thoroughly mixing, were higher than these ones by the adsorption method which pesticides dissolved in water were adsorbed to the soil. Another parameter (1/n), representing the linearity of adsorption, in Freundlich equation for the pesticides tested ranged from 0.96 to 1.02 by the desorption method and from 0.87 to 1.02 by the adsorption method. Therefore, the desorption method was more independent from pesticide concentration in soil solution than the adsorption method. By Soil Survey and Land Research Center (SSLRC)'s classification for pesticide mobility, alachlor and ethoprophos were classified into moderately mobile $(75{\leq}Koc<500)$, and ethalfluralin and pendimethalin were included to non-mobile class (Koc > 4000). Runoff and erosion loss of pesticides by three rainfall scenarios were from 1.0 to 6.4% and from 0.3 to 1.2% for alachlor, from 1.0 to 2.5% and from 1.7 to 10.1% for ethalfluralin, from 1.3 to 2.9% and from 3.9 to 10.8% for pendimethalin, and from 0.6 to 2.7% and from 0.1 % 0.3% for ethoprophos, respectively. Distribution of pesticides in soil profile were investigated after the simulated rainfall study. Alachlor and ethoprophos were leached to from 10 to 15 cm of soil layer, but ethalfluralin and pendimethalin were mostly remained at the top 5 cm of soil profile. The losses of the pesticides at 30% of sloping degree were from 0.2 to 1.9 times higher than those at 10%. The difference of their runoff loss was related with their concentration in runoff water while the difference of their erosion loss must be closely related with the quantity of soil eroded.

• Korean Journal of Weed Science
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• v.11 no.1
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• pp.26-31
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• 1991

The effects of varying concentrations and durations of ethalfluralin (N-ethyl-N-(2-methyl-2-propenyl)-2, 6-dinitro-4-(trifluoromethyl) bezenmine) treated on oat(Avena sativa L.) cell division, cell enlargement, protein synthesis and histology were studied. After 6hr treatment, all concentrations(1${\times}$10^{-6}M to $1{\times}10^{-3}$) of ethalfluralin arrested completely metaphase in the cell division study. The oat coleoptile inhibition of straight-growth test were used to determine the influence of ethalfluralin on coleoptile growth. A range of all concentrations($1{\times}10^{-8}$M to $1{\times}10^{-3}$M) treatment did affect cell enlagement significantly. The $1{\times}10^{-6}$M to $1{\times}10^{-3}$ M concentrations reduced approximately over 50% cell enlargement. Protein incorporation study showed that all concentrations($1{\times}10^{-6}$M to $1{\times}10^{-3}$M) were not affected in protein synthesis. To investigate histological effects, the oats were treated for 24hr with $1{\times}10^{-7}$M. The longitudinal section cells, in the treated oat root tips were appeared to be enlarged and also showed lacking cytoplasm, multinucleate or abnormal cells compare with untreated roots.

• Korean Journal of Weed Science
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• v.11 no.2
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• pp.117-121
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• 1991

This experiment was conducted to identify the relationships of concentration with phytotoxic rate of dinitroamide and acid amide herbicides which have showed the longest residual period in soil. Four herbicides treated showed greater inhibition on roots than shoots, greater inhibition by herbicides was obtained for Italian ryegrass than for Radish. Nitralin, pendimethalin, and ethalfluralin at 0.01ppm gave about 20% inhibition of Italian ryegrass roots, whereas about 47% inhibition was obtained with napropamide. Fifty percent inhibition($I_{50}$) of roots and shoots of Italian ryegrass was 0.036 and 0.132ppm for nitralin. 0.063 and 0.097ppm for pendimethalin. 0.042 and 0.092ppm for ethalfluralin. 0.027 and 0.071ppm for napropamide respectively. On the other hand, $I_{50}$ of roots and shoots of Radish was 1.028 and over 10ppm for nitralin. 1.925 and 4.885ppm for pendimethalin, 2.669 and over 10ppm for ethalfluralin, and 0.515 and over 10ppm for napropamide respectively. There was positive correlation between the concentration of herbicides and growth inhibition of Italian ryegrass and radish.

• 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.

• Korean Journal of Weed Science
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• v.14 no.4
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• pp.265-271
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• 1994

This study was conducted to determine the herbicidal activity, persistance, downward movement and effect on bentgrass of 7 dinitroaniline herbicides such as benefin [N-butyl-N-ethyl-2,6-dinitro-4-(trifluoromethyl) benzenamine], beslogine [N,N-dibutyl-2,6-dinitro-4-trifluoromethylaniline], prodiamine [2,4-dinitro-$N^3$,$N^3$-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine], pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine], trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl) benzenamine], ethalfluralin [N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl) benzenamine], and oryzalin [4-(diprop-ylamino)-3,5-dinitrobenzene-sulfonamide) together with bensulide [O,O-bis(1-methylethyl) S-[2-[(phenyl-sulfonyl) amino]ethyl]phosphorodithioate] and siduron [N-(2-methylcyclohexyl)-N'-phenylurea) as the control. In addition, distribution of pendimethalin and benefin into bentgrass was also determined. Prodiamine, benefin, and pendimethalin at the 1/16 dose of the recommended rate showed very high herbicidal activity($LD_{90}$) on Digitaria sanguinalis, but ethalfluralin and bensulide showed $LD_{90}$ at the 1/4 dose of the recommended rate, showing difference in herbicidal activities among dinitroaniline herbicides. All the herbicides except for pendimethalin had the lower herbicidal activity in sandy soil than that of clay-loam soil. Benefin, beslogine, prodiamine, oryzalin, bensulide and siduron persisted in the soil for about 50 days, but pendimethalin persisted in the soil for about 35 days, and trifluralin and ethalfluralin for about 25 days. Ethalfluralin, oryzalin and bensulide were the most mobile(downward movement) of the 9 herbicides studied. Less mobility was observed in the turfgrass condition than that of the bare soil. Beslogine bensulide prodiamine and benefin had no injury effect on bentgrass(Agrastis atolonifera L., penncross creeping bent grass). However, herbicides like oryzalin, trifluralin and pendimethalin reduced the dry weight of bentgrass by 12%, 30% and 40%, respectively. No significant difference in distribution of pendimethalin and benefin into inner part of leaves, surface and wax layer of bentgrass was observed, and thus it seems that different phytotoxic effect between pendimethalin and benefin may be attributed to different metabolism and mode of action.

• Korean Journal of Medicinal Crop Science
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• v.5 no.4
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• pp.255-259
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• 1997

The effects of slow-release fertilizer, C. D. U. (cyclo-di-urea), vinyl mulching and herbicides in different combinations were tested for weed control as well as the growth and yield of Cnidium officinale and economics were analyzed. Black vinyl mulching, ethalfluralin EC+white vinyl mulching, and ethalfluralin EC controlled weed completely till 60days after planting. When pendimethalin GR was sprayed more than 4.5kg/10a weed control value was $93.7{\sim}97.3%$, so significant difference was recognized with the recommended application rate (3.0kg/10a).

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.208-216
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• 1988

This study was conducted to select herbicides safe for cucurbitaceae crops under the polyethylene film mulching culture. No crop injury with ethalfluralin (N-ethyl-N-(2-methylally)-2, 6-dinitro-4-(trifluoromethyl) aniline) was found in gourd, water melon, cantaloup, cucumber and pumpkin of direct seeded culture. There was no significant reduction in fresh weight of gourd and pumpkin at the rate of 1080 g a.i./ha, that of water melon, cantaloup and cucumber at the rate of 720 g a.i./ha. Napropamide (N,N-diethyl-2-(${\alpha}$-naphthyloxy) propionamide) did not cause any crop injury at the rate of 1500 to 3000 g a.i./ha. There was no significant reduction in fresh weight of gourd, pumpkin and cucumber at the rate of 3000 g a.i./ha, and that of cantaloup and water melon at the rate of 1500 g a.i./ha. Trifluralin (${\alpha}$, ${\alpha}$, ${\alpha}$-trifluoro-2,6-dinitro-N, N-diprophlaniline) did not cause any crop injury in gourd. When ethalfluralin, napropamide and nitralin were applied to the transplanted seedlings of water melon and cantaloup, no significant reduction in the fresh weight were observed. The weeding effect greater than 90% was obtained with ethalfluralin at 720 to 1080 g a.i./ha and pendimethalin (N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine) at 1268 g a.i./ha. The rest treatment gave the weeding effect ranging from 81 to 90%.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.297-305
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• 2006

The field lysimeter experiment were undertaken to investigate the runoff and erosion loss of four pesticides from sloped land by rainfall and to assess the influence of pesticide properties, environmental factors and agricultural practices on them. The pesticide losses from soybean planted field and bare field were measured using field lysimeters. Pesticide losses from a series of lysimeter plots of sloped land by rainfall ranged $0.1{\sim}0.6%$ for alachlor, $1.1{\sim}4.5%$ for ethalfluralin, $8{\sim}31%$ for pendimethalin and 0.03% for ethoprophos, which were $1/3{\sim}2.5$ times to them in the simulated rainfall study. The erosion loss rates of pesticides from soybean-plots were $21{\sim}75%$ lower than the ones from bare soil plot. The effect of slope conditions was not great for runoff loss, but for erosion loss increased to maximum $4{\sim}12$ times by sloping degree and slope length. The peak runoff concentration in soybean-plots and bale soil plots were $3{\sim}278{\mu}gL^{-1}\;and\;6{\sim}450{\mu}gL^{-1}$ for alachlor, $1.1{\sim}11.4{\mu}gL^{-1}\;and\;0.9{\sim}16{\mu}gL^{-1}$ for ethalfluralin, $7{\sim}42{\mu}gL^{-1}\;and\;6{\sim}66{\mu}gL^{-1}$ for pendimethalin, and $2{\sim}53{\mu}gL^{-1}\;and\;0.1{\sim}113{\mu}gL^{-1}$ for ethoprophos, respectively, on nine different slope degree and slope length plots. Therefore, the differences of the peak runoff concentration between bare soil plots and soybean-plots were not great.