• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.105-115
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• 1996

In this paper, we reviewed the degradation factors of diazinon which was known to be easily degraded by soil microorganisms and lost of its activity. Under submerged soil condition, the contribution of microorganisms to diazinon degradation was about 40% and these microorganisms preferred soil humus as substrates to diazinon itself. The effect of monooxygenase activity in submerged soil was more important than esterase activity on diazinon degradation and these enzymes were inhibited by several chemicals such as piperonyl butoxide(PBO), EPN and tricyclazole. From these results, new formulation type of diazinon (PBO and triphenyl phosphate were added to commercial diazinon formulation by 0.1% respectively.) and diazinon mixture formulation (diazinon was mixed with EPN, tricyclazole and carbofuran in equal amount) were prepared. The new formulation type of diazinon showed better insecticidal activity by 12% and more delayed diazinon degradation in ten days than commercial diazinon.

• Korean Journal of Microbiology
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• v.27 no.2
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• pp.139-146
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• 1989

The mechanisms and metabolic products involved in the degradation of an organophosphate insecticide, diazinon, were studied in submerged paddy soil under the laboratory condition at $30^{\circ}C$. Diazinon abatement in non-sterilized soil was more rapid than indicating microbial participation in diazinon in soil. One-half of the original applications was lost in 2 days and less than 5% remained after 7 days. During the same period, dizinon applications increased tha microbial populations in accordance with the monooxygenase and esterase activities in soil. These results suggest that the microbiological factors develop in soil following diazinon application. The esterase and monooxygenase-catalyzing degradation products of diazinon were isolated and tentatively identified by mass spectrometryas 2-isopropyle-6-methyl-4-hydroxy pyrimidine, diazoxon, hydroxydiazinon, and sulfotep.

• Korean Journal of Environmental Agriculture
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• v.12 no.1
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• pp.35-40
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• 1993

In order to find the effect of humic substances affecting to the behavior of diazinon in submerged soil, the adsorption rate of diazinon was investigated with different soil humic substances like as humin, humic acid and fulvic acid. The adsorption rate of diazinon(1.8 ppm) was 12.4% in humin, 11.9% in fulvic acid and 10.4% in humic acid at 1% concentration of humic substances, also were not much differences at 0.1 and 0.5%. But it showed much similar level ($10.2{\sim}10.6%$) at 1.0% concentration in 5ppm diazinon treatment. As a result, because adsorption rate of diazinon on humic substances were about $10{\sim}12%$, disappearance of diazinon in submerged soil may be affected by the other factors such as soil microorganism.

• Korean Journal of Environmental Agriculture
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• v.11 no.2
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• pp.109-115
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• 1992

In order to investigate waether soil microorganism prefer diazinon to humic substances as their substate, the growth of soil bacteria and the activities of monooxygenase and ${\alpha}-,{\beta}-esterase$ were measured after treatment of diazinon and humic substances in defined medium at $30{\pm}1^{\circ}C$. Also, the degradation rate of diazinon was determined by addition of humic substances to the medium. The number of soil bacteria was increased from 1 day and 3 days after the treatment with humic substances and diazinon, respectively. And it showed about 1.5 times more with humic substances than diazinon at 10 days. Monooxygenase(MO) activity with the treatment of humic substances was higher than diazinon until 3 days after treatment in the order of HA > FA > humin. Esterase(ES) activity with the treament of humin and HA was higher than dizainon from 5 dyas, but FA was much similar to diazinon. The degradation rate of diazinon showed more persistancy by addition of humic substances ; 51.4% with humin treatment, 58.9% with HA, 62.4% with FA and 71.9% in control at 10 days after treatment. Therefore, as soil microorganisms perfer humic substances to diazinon, the degreadation rate of diazinon might be delayed by addition of humic stbstances in submerged soil.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.328-333
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• 1997

A study was conducted to examine the effect of application of Diazinon at different rates in submerged soil under the application of different N fertilizers; urea, ammonium sulfate and organic fertilizer(fermented chicken dung-sawdust mixture). The levels of Diazinon application were equivalent to zero, 350 mg a. i./ha, 700 mg a. i./ha and 1050 mg a. i./ha. To 100 gr of air-dry soil, 10 mg of N, $P_2O_5$ and $K_2O$ and different levels of Diazinon were mixed thoroughly and the soil was submerged in 100 ml of distilled water. The submerged soil was incubated at $30^{\circ}C$ for 50 days. Volatilied ammonia was measured at every 10 days. The amount of ammonia volatilization was greatest in urea treated soil, followed by organic fertilizer and it was the least in ammonium sulfate treated soil. The application of Diazinon at 700 mg a. i./ha increased the volatilization of ammonia greatly in the urea treated soil. Under other fertilizers, the effect of Diazinon application was not remarkable. The increase in the soil pH during the incubation period under different fertilizer treatments tended to increase ammonia volatilization.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.391-399
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• 2018

In this study, Diazinon which is the most widely used organophosphorus pesticides (OPPs) among pesticides was removed by ozone/hydrogen peroxide advanced oxidation process (Peroxone AOP). Diazinon is mainly found in groundwater, drinking water, rivers and ponds that are near agricultural areas using the pesticide. Accumulation of Diazinon on the body in the form of metabolites causes neurotoxicity, confusion, dizziness and vomiting. Diazinon is not easily removed by conventional water treatment processes. This study investigated the Diazinon removal characteristics with OH radicals with strong oxidizing power generated by using ozone and hydrogen peroxide. We determined optimal hydrogen peroxide/ozone injection molar ratio and confirmed the elimination reaction to initial Diazinon concentration, pH and DOC concentration, which are factors influencing the removal efficiency. Domestic researches on pesticide removal in the environment are much less than the cases of overseas. This study is expected to provide a basis for the process design for pesticide removal.

• Korean Journal of Environmental Agriculture
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• v.9 no.2
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• pp.153-159
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• 1990

Two fractions(microsomal and soluble) were prepared by ultracentrifugation(105,000G for 1hr at $4^{\circ}C$) from pig liver in order to find the major factor in Diazinon degradation. The two enzyme activities showed the same value, but Diazinon was degraded three times in microsomal fraction more than in soluble fraction. And with addition of EPN, Beam and PBO, degradation of diazinon was inhibited(29, 30 and 60%) as well as Monooxygenase activity (14, 15 and 35%) in microsomal fraction, respectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.3-6
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• 1999

Several chemical washing procedures were applied to Parathion and Diazinon contaminated soil. Batch and column tests were performed to determine the insecticides extraction efficiency as a function of pH. Washing efficiency of methanol is more higher than that of water and HCl when washed parathion and diazinon are. Those are completely miscible with most organic solvents. For parathion, release trend is increased as pH is increased because it is hydrolyzed easily at the condition of alkali. But diazinon shows reverse because diazinon is decomposed rapidly at the condition of acidic So, diazinon is more released than parathion is because this experiment is peformed in acidic and weak acidic conditions. Generally, parathion and diazinon are classified as having low mobility, so they can be easily controlled if the proper washing process are applied.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.332-338
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• 2010

Degradation characteristics of insecticide diazinon in upland and paddy soils under laboratory conditions were investigated to elucidate the effect of raw pig slurry (RPS) and processed pig slurry (PPS) treatment. Soil (20g) was treated with RPS and PPS by standard rate, double rate and triple rate before treating with diazinon (0.5mg/kg level) and incubating at ($25{\pm}2^{\circ}C$) for 60 days. The half-lives of diazinon in the untreated upland and paddy soil were about 28 and 22 days respectively. The degradation rate of diazinon was faster by $5.0{\pm}1.2$ days in the paddy soil than in the upland soil independent of fertilizer types. This result indicates that soil moisture content affects the half-life of diazinon probably by hydrolysis. Degradation of diazinon was faster in RPS treatment soil than in PPS treatment soil. The more amount of fertilizers were treated, the more rapidly diazinon degraded regardless of fertilizers and soil types. Based on the results obtained, degradation of diazinon in soil was definitely influenced by soil water contents and treatment of those fertilizers.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1087-1094
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• 2008

Diazinon is a phosphorothiate insecticide widely used in the world including Korea. This study investigates the feasibility of photolysis and photocatalysis processes for the degradation of diazinon in water. Both photolysis and photocatalysis reactiosn were effective in degrdading diazinon, however lower TOC removals were achieved. In case of photocatalysis, approximately 40% of nitrogen from diazinon was recovered as NO$_3^-$, and less than 5% of phosphorus as PO$_4{^{3-}}$. However, the sulfur in diazinon molecule was completely recovered to SO$_4{^{2-}}$ from photocatalysis reaction, and the recovery from photolysis was 50%, indicating that P=S bond easily breaks first during photolysis and photocatalysis. The poor recoveries of ionic byproducts and TOC from photolysis and photocatalysis indicate the presence of other organic intermediates during reactions. The formation of organic intermediates were identified during reactions using GC/MS and LC/MS/MS, and the main degradation products were diazoxon, and 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMP), respectively. Finally, the acute 48-hr toxicity test using Daphnia magna were employed to measure the toxicity reduction during photocatalysis of degradation. The results showed that the toxicity increased until 180 min of the photocatalysis reaction (from EC$_{50}$ (%) of 69.6 to 13.2%), however, acute toxicity completely disappeared (>100%) after 360 min. The toxicity results showed that the intermediates from photocatalysis such as diazoxon were more toxic than diazinon itself, however these intermediates can be degraded or mineralized with further reaction.