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Given the mode of transmission of Middle East respiratory syndrome (MERS), healthcare workers (HCWs) in contact with MERS patients are expected to be at risk of MERS infections. We evaluated the prevalence of MERS coronavirus (CoV) immunoglobulin (Ig) G in HCWs exposed to MERS patients and calculated the incidence of MERS-affected cases in HCWs. We enrolled HCWs from hospitals where confirmed MERS patients had visited. Serum was collected 4 to 6 weeks after the last contact with a confirmed MERS patient. We performed an enzyme-linked immunosorbent assay (ELISA) to screen for the presence of MERS-CoV IgG and an indirect immunofluorescence test (IIFT) to confirm MERS-CoV IgG. We used a questionnaire to collect information regarding the exposure. We calculated the incidence of MERS-affected cases by dividing the sum of PCR-confirmed and serology-confirmed cases by the number of exposed HCWs in participating hospitals. In total, 1169 HCWs in 31 hospitals had contact with 114 MERS patients, and among the HCWs, 15 were PCR-confirmed MERS cases in study hospitals. Serologic analysis was performed for 737 participants. ELISA was positive in five participants and borderline for seven. IIFT was positive for two (0.3%) of these 12 participants. Among the participants who did not use appropriate personal protective equipment (PPE), seropositivity was 0.7% (2/294) compared to 0% (0/443) in cases with appropriate PPE use. The incidence of MERS infection in HCWs was 1.5% (17/1169). The seroprevalence of MERS-CoV IgG among HCWs was higher among participants who did not use appropriate PPE.

The proficiency testing for the residue laboratories of pesticide registration was conducted inorder to improve the reliability and the ability for pesticide residue analysis. On November 2012 the testingwas carried out using the soil collected and kept as the moistened state for five years, which was expected tovery low residue levels of pesticides. The soil was fortified with azoxystrobin, imidacloprid and methabenz-thiazuron in a manner similar to prepare soil samples for indoor soil degradation test, and then sub-sampleswere prepared for the distribution to participants. Some of them were randomly selected for confirm ofhomogeneity and to ensure the stability of samples at room temperature. Samples were consisted of two soilstreated as different levels, one of which was used to the assessment and another used to confirm. In addition,provided three standard solutions, respectively concentration of 10 mg/L, and untreated soil. Forty eightinstitutions submitted results. The medians of results were used as the assigned values for pesticide residues.Fitness for purpose standard deviation of proficiency test was calculated by applying 20% RSD as thecoefficient of variation allowed in the soil residue test. Z-score was applied for evaluation of individualpesticides, and the average of the absolute value of the Z-score for the overall assessment of pesticides.Laboratories evaluated the absolute value of the Z-score less than 2 to fit the case of azoxystrobin were 48,imidacloprid and methabenzthiazuron 46.Key words pesticide, residue analysis, quality assurance, proficiency test

Pesticide is used to protect the crops, but also become a cause of polluting the environment.Perform a risk assessment using physical and chemical properties, environmental fate and toxicity data inorder to determine the pesticide registration. The aquatic model estimates pesticide concentrations in waterbodies that result from pesticide applications to rice paddies and apple orchard. The used models are thePRZM, EXAMS and AGRO shell (PA5), Rice Water Quality Model (RICEWQ) and Screening ConcentrationIn GROund Water (SCI-GROW). The residual concentration of water body was estimated using meteorologicaldata, crop calendar and soil series of Korea. The chosen pesticides were butachlor, carbofuran, iprobenfos andtebuconazole. It has shown the potential that the RICEWQ is possible to predict residue level in water ofbutachlor and iprobenfos, because the maximum value in water monitoring data is lower than the peakconcentration of the model, and the minimum value is lower than the average annual concentration of themodel. But RICEWQ was insufficient to predict exposure concentrations in ground water. The estimatedexposure concentrations of carbofuran in ground water is very higher than in surface water because of its lowsoil adsorption coefficient. Although tebuconazole were not detected in the water monitoring that means verylow concentration, it is possible that the PA5 can be used to predict residue level in water.Key words rice paddies, water model, RICEWQ, SCI-GROW, PA5

The test method of aerobic transformation in soil has established based on international testguideline (OECD TG 307). And then, the case study was conducted with [ 14 C]butachlor. Butachlor iscommonly used herbicide in Korea. [ 14 C]Butachlor was treatrd 6.83 mgKg −1 in loamy soil. The treated soilwas incubated in flow-through system for 60 days. The mass balance of applied radioactivity (AR) rangedfrom 91.1 to 95.5% and from 93.0% to 97.7% for non-sterile and sterile soils, respectively. In non-sterile soil,the concentration of [ 14 C]butachlor was declined from 94.4% AR at 0 day to 8.4% AR at 60 days aftertreatment. 2-Chloro-2',6'-diethylacetanilide was the major degradation product detected in soil extract. Thecalculated DT 50 and DT 90 of butachlor were 10.4 days and 34.6 days, respectively. 14 CO 2 and non-extractablesoil residue were increased up to 3.5% and 43.5% AR at 60 DAT. There is no significant decrease of the[ 14 C]butachlor through the incubation period in sterile soil. Key words soil metabolism, aerobic, OECD TG 307, butachlor

This study was carried out to investigate the pesticide residue pattern among different leafyvegetables applied with foliar spraying under greenhouse and to check extrapolating from some residue trialdata to other minor crops. Leafy vegetables used in this study were: Mustard greens (Brassica juncea L.),Kale (Brassica oleracea L.), Dacheongchae (a kind of pak-choi (Brassica rapa subsp. chinensis L.)), Leafbroccoli (Brassica oleracea var alboglabra), Perilla leaf (Perilla frutescens (L.) Britton var. Frutescens), Leaflettuce (Lactuca sativa L.), Swiss chard (Beta vulgaris L. subsp. vulgaris) and Red leaf chicory (Cichoriumintybus L. var. foliosum Hegi). These are cultivated all year under indoor or outdoor and cut the leaf fromplant continuously during harvest time. The amounts of pesticide deposit in/on the continuous harvestingleafy vegetables were affected by the ratios of leaf area to weight. Ratio of perilla leaf was the largest amongcrops as 58 cm 2 /g. The residue levels of 7 pesticides in/on perilla leaf were the highest than those of othercrops through the statistical analysis from zero day to fifth day after last application. The representative cropin 8 crops was perilla leaf selected based on the amounts of daily consumption and the high residues. This studysuggest that the continuous harvesting leafy greens should be separated from the one time harvesting leafyvegetables for the pesticide recommendations because of different harvesting habits and pre-harvest intervals.Key words Extrapolation, Perilla leaf, Leafy vegetables, Pesticide residue, Continuous harvesting

The field lysimeter study was undertaken to investigate influence of agricultural practice and topography on runoff and erosion loss of fluazinam from the sloped land grown pepper. The WP type formulation was applied on July in 2003~2005. The wash-off rates were from 1.4% to 8.4% of the applied fluazinam. The runoff losses of fluazinam from a series of pepper grown-lysimeter plots were 0.14~0.90% in the first year, 0.01~0.04% in the second year and 0.16~0.37% in the third year for the mulched contour ridge plots, 0.47~1.59% for the mulched up-down direction ridge plots and 0.07~1.05% for the no-mulched contour ridge plots as the control, and they increased with slope degree. Concentrations of fluazinam in runoff water ranged mostly to 10 µ gL at the first runoff event. Erosion rates from plots except the mulched up-down direction ridge plots was 0.00~0.21% for 10% and 20% slope-plots and 0.15~1.05% for 30% slope-plots with different slope degrees. Erosion rates from the mulched up-down direction ridge plots were 0.47~1.59% for 10% slope-plots and 0.75~1.05% for 20% slope-plots. Residues of fluazinam in soil at ten days after the application ranged from 0.007 mg kg to 0.059 mg kg except the soil under the mulch. After then the fluazinam residue in soil was dissipated at the rate of 20 days of half-life to below 0.01 mg kg at 60 days after the application.

The objective of this study was to investigate the exposure assessment of Korean consumers toedifenphos and tricyclazole in cattle product fed the rice straw, using a probabilistic approach. We usedtricyclazole and edifenphos residue data in rice straw reported by National Academy of Agricultural Science(NAAS) for the 1998, 1999, 2001 and 2010 monitoring study and National Agricultural Products QualityManagement Service (NAQS) for 2009 monitoring study. The mean exposures of edifenphos and tricyclazole forall of Korean consumers were 0.027% and 0.0006% of ADI and 99% th percentile exposures were 0.034% and0.0007% of ADI respectively. The group of 1~6 years old consumers has the lowest exposure of edifenphos andtricyclazole. The group of 19~29 years old consumers has the highest exposure of edifenphos and tricyclazole.Key words Pesticide residue, Rice straw feed, Cattle by-product, Exposure assessment, Probabilistic approach 서론 볏짚은 우리나라에서 이용되는 가축 조사료의 40~50%를차지하는 작물로 매년 2백만 톤 안팍의 볏짚이 사료용으로이용되고 있다(MAFF, 2010). 볏짚은 쌀을 생산하는 과정에서 나오는 일종의 부산물로 벼의 병해충 방제를 위하여 사용한 농약이 볏짚에 잔류할 수 있다. WHO/FAO에서는1989년부터 식품 중 잔류농약의 오염평가 시 위해성평가기법을 도입하여 노출에 대한 안전성 여부를 판단하고 있다(FAO/WHO, 1997). 국내에서도 이러한 위해성평가기법을도입하여 식품 섭취에 의한 농약의 노출평가들이 보고되고있는데, 대부분이 농산물 섭취에 대한 평가이다(Do 등,2013; Paik 등, 2010). 사료에 대한 평가는 권 등(2000)이 볏짚의 잔류농약 모니터링결과를 농약의 일일섭취허용량과 대비하여 평가한 사례가 있으나 이 경우 볏짚을 섭취하는 소(400 kg)를 대상으로 평가한 것으로 실제 사람이 볏짚을 섭취한 소의 식육을 섭취할 경우에 대한 평가는 이루어진바없다. 농약의 인체에 대한 위해성평가는 해당 농약의 독성자료와 노출자료를 고려하여 유해물질의 유해영향 발생확률을 계산함으로써 평가하는 방법이다(Henry, 1997). 이러한위해성평가는 노출량, 섭취량, 체중 등의 변수를 단일 값만이용하여 평가하는 확정론적 접근법과 모든 변수들을 분포측면에서 고려하여 평가하는 확률적 접근법이 있다. 확정론적 접근법은 평가방법이 간단하고 이해가 쉽다는 이점 때문에 노출수준을 확인하는 일차적인 접근으로 주로 사용되고

A series of monitoring studies were carried out to evaluate the residue level of pesticides in different native soils from 1999 to 2006. The nation-wide collection of soil samples from paddy, greenhouse, upland and orchard, were analyzed by GLC (ECD or NPD) and GC/MS. The results obtained are summarized as follows; out of 14 pesticides detected from paddy soils in 1999, the highest residue level was 0.25 mg kg , and the frequency was 21.7% as butachlor, 20.0% as isoprothiolane, and 16.7% as iprobenfos. In 2003, 7 pesticides were detected and their frequencies were 0~36.0%; the frequency was 36.0% as isoprothiolane and 33.3% as oxadiazon. In the year 2000, 57 pesticides in the greenhouse soil samples were detected with the highest frequency of 65.3%. Of the pesticides detected, endosulfan and procymidone showed the frequency of 65.3 and 50.0%, respectively. In 2004, 19 pesticides were detected from greenhouse soils, and their frequencies and residue levels were decreased. Endosulfan and procymidone showed high detection frequencies and concentrations of 21.3 and 9.3% and 0.76 and 0.31 mg kg , respectively. In 2001, a total of 25 pesticides were detected through monitoring in 170 upland soils and the highest residue level was 2.24 mg kg . The detection frequencies showed the range of 0~53.5%. Especially, endosulfan showed the highest frequency of 53.5%. Residue levels and frequencies of pesticide in the year 2005 were almost the same compared with that of the year 2001. As a result of monitoring in 150 orchard soils in 2002, 26 pesticides were detected and the highest residue level was 1.43 mg kg . Of them, the frequency of endosulfan showed the highest as 45.3%. In 2006, 20 pesticides were detected in orchard soils. The frequency of total endosulfan was the highest as 5.3% but was lower than that of the year 2002.

Pesticides were sprayed on perilla leaf and leafy lettuce in a greenhouse and the reduction rate ofpesticide residues on each vegetable by washing were tested. The reduction rate of pesticide residues bywashing for 30 sec~3 min on perilla leaf were 3~63% in tap water, 2~58% in salt water, 6~74% in green teawater, and 8~86% in detergent solution. The detergent solution only showed significant difference inreduction rates compared to the tab water washing. Considering reduction effects of the washing duration, itwas showed that the reduction rates were a pattern of inclining as the duration of washing process increased,but there was no significant difference in the reduction rates except the reduction rates between washing inthe detergent solution for 1 min and 3 min. Comparing washing in flowing tab water and in stagnant tabwater with leafy lettuce, the reduction rate by one time washing were 8~68% in flowing tab water and7~64% in stagnant tab water. The water and the time used in this experiment were 17.5 L, 2.9 min withflowing tab water and 4 L, 1 min with stagnant tab water. The reduction rate by 3 times washing in stagnanttab water were 16.5~76.6%, and the water and the time used were 12 L, 3 min. Therefore, when the waterand the time used to wash vegetables were considered, washing two or three times in stagnant tab watercould be more effective than washing one time in flowing tab water.Key words Pesticide residue, Leafy vegetable, Washing, Reduction

The proficiency testing for the residue laboratories of pesticide registration was conducted in order to improve the reliability and the ability for pesticide residue analysis. On October 2011 the testing was carried out using the soil collected and kept as the moistened state for five years, which is expected to very low residue levels of pesticides. The soil was fortified with chlorpyrifos, metolachlor and procymidone in a manner similar to prepare soil sample for indoor soil degradation test, and then sub-samples were prepared for the distribution to participants. Some of them were randomly selected for confirm of homogeneity and to ensure the stability of samples at room temperature. Samples were consisted of two soil treated as different levels, one of which was used to the assesment and another used to confirm. In addition, provide three standard solutions, respectively concentration of 10 mg/L, and untreated soil. Forty seven institutions submitted results. The medians of results were used as the assigned values for pesticide residues. Fitness for purpose standard deviation of proficiency test was calculated by applying 20% RSD as the coefficient of variation allowed in the soil residue test. Z-score was applied for evaluation of individual pesticides, and the average of the absolute value of the Z-score for the overall assessment of pesticides. Laboratories evaluated the absolute value of the Z-score less than 2 to fit the case of chlorpyrifos and procymidone were 44, metolachlor 40.

This study was carried out to clarify the effects of the application of pesticide by different spray nozzle types on pesticide residues. The average droplet size and discharge rate were investigated when the manual compressed sprayer with two head disk type nozzle and the knapsack engine powered sprayer with two head fan shape nozzles were used. The fan type nozzles were classified into three types by the number of orifice in the nozzle. Three type nozzles tested were fan with one orifice, fan with two orifices and fan with three orifices. Fan (trade name : D-3) with 2.4 L/min. of the discharge rate and 76 µm of the average droplet size while maintaining constant pressure 1.1 ± 0.2 MPa, and fan D-35 with 2.6 L/min. and 90 µm while maintaining constant pressure 1.0±0.2 MPa were appropriate. The orifice size of D-3 was 0.65 mm length × 0.45 mm width and the orifice size of D-35 was 0.62 mm length × 0.46 mm width. The residue levels of imidacloprid on perilla leaves among four applications by four different nozzles show significantly difference with 5% significance level. The residue levels 3.76~3.92 mg kg �1 by fan or disk type is smaller than 4.52~4.92 mg kg �1 by fan II or fan III. The residue levels of imidacloprid on perilla leaf were different

This study was conducted for the establishment of the analytical method of pesticide residues in rice straw for 9 pesticides; etofenprox, tricyclazole, diazinon, edifenphos, propiconazole, carbaryl, carbofuran, 3-hydroxy carbofuran and 3-keto carbofuran and for the monitoring of these pesticides in rice straw for livestock feed in Korea. These pesticides were classified into 4 groups according to analytical instrument condition. Group 1 (HPLC-UVD1) included tricyclazole and etofenprox while group 2 (HPLC-UVD2) included propiconazole and edifenphos. Group 3 (HPLC-FLD) included carbaryl, carbofuran, 3-hydroxy carbofuran and 3-keto carbofuran. Group 4 (GC-NPD) included Diazinon. The dried rice straw samples were extracted with acetone and purified by liquid-liquid partition and solid phase extraction (SPE): Combination of Florisil SPE and amino-propyl SPE was used for group 1 and group 2, amino-propyl SPE for group 3, and Florisil SPE was for group 4. Recovery was in the ranged 70~110% and the limits of quantitation (LOQ) were lower than the half of maximum residue limits. Therefore this method was proved to be efficient for monitoring of these pesticides residue in rice straw. A total of 18 rice straw samples from 6 provinces in Korea in 2010 were analyzed using established method and, only 3-keto carbofuran was detected in one sample at concentration of 0.04 mg/kg. Key ward Rice straw, Pesticide residue, Analytical method, Monitoring

Performance of proficiency testing and the validation of analytical method was included ascheme of quality assurance in analytical chemistry laboratory to monitor a laboratory’s performance abilitiesand produce consistently reliable data. This study was assessed the applicability of proficiency testing schemeproposed for analytical laboratories of pesticide product in domestic. The validation of analytical methods,stability and homogeneity for formulated pesticide products (emulsifiable concentrate) of emamectin benzoateand lufenuron was confirmed for the proficiency testing. The z-score of 33 participation laboratories foremamectin benzoate were that the numbers of outlier were 2 laboratories (6.0%), z-score outside the rangefrom −3 to 3 designated “unaccptable” were 2 laboratories and z-score in the ranges −2 to −3 and 2 to 3designated “questionable” were 3 laboratories (9.0%). Three laboratories (9.0%) showed the z-scoredesignated “questionable” for lufenuron. The additional proficiency testing for various product types will beneeded to establish the scheme of quality control.Key words Homogenity, Pesticide formulation, Proficiency test, Stability

Fate of acetamiprid and imidacloprid aerially sprayed to control pine wood nematode (Bursaphelenchus xylophilus) were studied in a forest of Haman area. Acetamiprid 20% SL or imidacloprid 20% DC were diluted 100 times and applied two times as rate of 50 L/ha using an aircraft of Bell 206 L helicopter. Average acetamiprid deposits on forest floor ranged from 2 to 4% of standard aerial application rate. Following to the second application, acetamiprid deposits in the pine needle ranged 1.8~8.5 mg/kg and then gradually decreased to 1.2~2.1 mg/kg after 48 days. Deposits on the plant washed off by rainfall and reached to soil surface was ca. 17% of the application rate. All of acetamiprid on the ground resided in the forest floor covering the soil surface, where acetamiprid residues were decreased to a quarter at 48 days after the second application, but they were not detected in soil beneath it. And the only low level of acetamiprid residues, 0.0003 mg/L, was detected in the reservoir nearby the experimental forest on the day of aerial application. The acetamiprid detection was presumably due to spray drift. And average imidacloprid deposits on forest floor ranged from 1 to 3% of standard aerial application rate. Following to the second application, imidacloprid deposits in the pine needle analysed very low concentration of 0.1 mg/kg, but the amount of imidacloprid in wash-off in standard and two-fold treatment were ca. 8% and 4% of the application rate, respectively. Most of imidacloprid on the ground also resided in the forest floor, where imidacloprid residues were decreased to a twentieth at 111 days after the second application, and they were detected below 0.5% of the application rate in sol beneath it. And the low level of imidacloprid, 0.0003~0.0017 mg/L, were detected in the streams in the experimental forest. It was not to the level of contamination concerns.

This study was carried out to clarify effects of field location and sprayer on the level of pesticide residue in chilli peppers. As confirmed by statistical analysis, the residue levels in green pepper among three greenhouses did not show significant difference at the first day after spraying with the same engine sprayer and nozzle. But the residue levels in green peppers collected from the exposed outside of crop were 2 times higher than those from the hidden inside. The sampling site was one of variation elements of pesticide residue. The residue levels after application by knapsack engine powered sprayer were 1.7 times higher than those by manual compressed sprayer. As the spraying pressure of the engine power sprayer is 2 times higher than the commonly used pressure of the manual compressed sprayer, the pressure of the sprayer and nozzles were considered to affect on the residue levels in peppers.

The characteristics of chlorpyrifos was studied to clarify the effect of the cultivation season,spray intervals, spray volume and concentration on residues in chilli and sweet peppers cultivated undergreenhouse condition. Residue levels of chlorpyrifos detected in chilli pepper fruit cultivated were 1.5 to 2.7times higher in winter(February-March) than those in summer(June-July). During winter season residue levelsof chlorpyrifos in chilli peppers were 6.9~3.2 times higher than those in sweet peppers for 10 days after 3times application with 7 days interval. Residue levels in chilli pepper were from 2.070 mg/kg at 1 day to0.929 mg/kg at 10 day, while those in sweet pepper were from 0.302 mg/kg to 0.291 mg/kg. Residue levels insweet pepper to which are 3 times applied with 7 days interval were from 0.302 mg/kg at 1 day to 0.291 mg/kg at 7 day, and the residue levels in sweet pepper which are 3 times applied with 3 days interval were from0.498 mg/kg at 1 day to 0.470 mg/kg at 7 day. Residue levels of chlorpyrifos in the sweet peppers applied bydouble concentration were 2.5 times higher than those sprayed by normal standard amounts diluted in doublevolume. Key words Chlorpyrifos, Sweet pepper, Chilli pepper, Pesticide residue

Three different experiments were carried out to investigate the runoff and erosion losses of endosulfan from sloped-field by rainfall. The mobility of endosulfan and which phase it was transported by were examined in adsorption study, the influence of rainfall pattern and slope degree on the pesticide loss were evaluated in simulated rainfall study, and the pesticide losses from soybean-grown field comparing with bare soil were measured in field lysimeter study. Adsorption parameter (K) of endosulfan ranged from 77 to 131 by adsorption method and K values by the desorption method were higher than those by the adsorption method. By the SSLRC's classification for pesticide mobility endosulfan was classified as non-mobile class ($K_{oc}>4,000$). Runoff and erosion loss of endosulfan by three rainfall scenarios ranged from 3.4 to 5.6%and from 4.4 to 15.6%of the amount treated. Endosulfan residues were mainly remained at the top 5 cm of soil depth after the simulated rainfall study. Pesticide loss in case of 30%-slope degree ranged from 0.6 to 0.9 times higher than those in case of 10%-slope degree. The difference of pesticide runoff loss was related with its concentration in runoff water and the difference of pesticide erosion loss would related closely with the quantity of soil eroded. Endosulfan losses from a series of lysimeter plots in sloped land by rainfall ranged from 5 to 35% of the amount treated. The erosion rate of endosulfan from soybean-plots was 66% of that from bare soil plots. The effect of slope conditions was not great for runoff loss, but was great for erosion loss as increasing to maximum times with slope degree and slope length. The peak runoff concentration of endosulfan in soybean-plots and bare soil plots ranged from 8 to 10 and from 7 to on nine plots with different slope degree and slope length. Therefore the difference of the peak runoff concentrations between bare soil plots and soybean-plots were not great.

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 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.

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 for alachlor, for ethalfluralin, for pendimethalin and 0.03% for ethoprophos, which were times to them in the simulated rainfall study. The erosion loss rates of pesticides from soybean-plots were 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 times by sloping degree and slope length. The peak runoff concentration in soybean-plots and bale soil plots were for alachlor, for ethalfluralin, for pendimethalin, and 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.

In order to elucidate the adsorption and leaching characteristics of the insecticide imidacloprid in two types of paddy soils near Suwon, this experiment was carried out with imidacloprid as a radiotracer. In an adsorption study conducted using imidacloprid in 2 test soils, the adsorption coefficient was higher in soil A than that in soil B . As calculated from Freundlich constant, distribution coefficients and half lives in soils, GUS indices showed low leachabilities of imidacloprid treated on the paddy soils into the groundwater. The amount of imidacloprid leached from the soil columns during the 4 weeks of leaching was less than 2% of the originally treated . In the leaching test the amounts of activities distributed in the soil layer of 0-10 cm were more than 80% of the originally tented and those in rice plants were less than 3% of the originally treated , suggesting that imidacloprid has very low teachability and bioavailability.

This study was conducted to investigate the downward mobility of pesticides using soil columns and to compare the experimental results with values predicted from Convective mobility test model. Nine pesticides such as metolcarb, molinate, fanobucarb, isazofos, diazinon, fenitrothion, dimepiperate, parathion and chlorpyrifos-methyl were used for leaching test in soil column for four soils; Jungdong (upland soil), Gangseo (paddy soil), Yesan (forest soil), and Sineom(upland, volcanic ash-derived soil) series. The peak concentrations leached from 10 cm-columns of three soils except Sineom series ranged 6.5 to 12.6 mg/L for metolcarb, 2.6 to 5.0 mg/L for molinate, 4.5 to 7.8 mg/L for fenobucarb, 0.39 to 1.36 mg/L for dimepiperate, 1.1 to 4.6 mg/L for isazofos, 0.01 to 0.14 mg/L for diazinon, lower than 0.01 to 0.70 mg/L for fenitrothion and lower than 0.01 to 0.44 mg/L for parathion. But chlorpyrifos-methyl was not leached from any soil columns. Elution volumes to reach the peak of metolcarb, molinate, fenobucarb, isazofos, diazinon, and dimepiperate in the leachate ranged 1.1 to 2.1 pore volume (PV), 1.6 to 3.3 PV, 1.6 to 3.3 PV, 2.1 to 4.4 PV, 6 to 15 PV, and 8 to 21 PV, respectively. On the same water flux conditions, convection times estimated by Convective mobility test model were coincided with results from soil column test in most of the soil-pesticide combinations applied. Based on convection times estimated by the model at standard conditions (water flux 1 cm/day), metolcarb was classified as most mobile, molinate, fenobucarb and isazofos as mobile or most mobile, dimepiperate as moderately mobile or mobile, diazinon as mobile, fenitrothion and parathion as slightly mobile or mobile and chlorpyrifos-methyl as immobile or slightly mobile.