• Journal of agricultural medicine and community health
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• v.18 no.1
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• pp.55-63
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• 1993

A simultaneous determination method by HPLC for egg-residues sulfamerazine, sulfamethazine, sulfadimethoxine, furazolidone and zoalene was assesed. The drugs were extracted by dechloromethane, The extract after solvent evaporation, is partitioning in hex ane/water and back-partitioning in dechloromethane and analysis by HPLC. The average recovery rates of the above microbials from the egg spiked standard solution were approximately 81.2%, 87.6%, 92.5%. 86.1% and 79.3% respectively. The limit of detection of sulfamerazine. sulfamethazine and sulfamethoxine were in the levels of 0.2ppb, furazolidone and zoalene 0.5ppb respectively. According to this method 84 commercial eggs were examined. Sulfamethanzine was detected at levels of 0.005-0.008ppm in 3 eggs. Sulfadimethoxine was detected at levels of 0.012-0.019ppm in 4 eggs. No sulfamerazine, furazolidone and zoalene was detected in every samples. The residues of antimicrobial agent were safety level as food generally.

• Journal of Environmental Health Sciences
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• v.7 no.2
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• pp.89-95
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• 1981

A Continuous monitoring of Air Pollution in city of Seoul was carried out from January 1 to December 31 of 1979 at two selected sites, Kwanghwamun observatory and Kwanag observatory. The measured data were averaged on monthly basis. The maximun value of oxidant pollution was observed in July, and the minimum in February. It is the purpose of this study to determine the effect of hydrocarbon, nitrogenoxide, wind velocity and ambient temprature on the observed values of oxidant pollution for the above two months. The results of the study may be summarized as follows. 1) The oxidant concentration in February was higher than in July by about 2 times in both downtown area and the suburbia. The concentration in downtown area was $25.75\pm 4.75ppb$, and that in suburbia was $29.83\pm 5.16ppb$. As for the oxidant concentration in July, it was observed that the suburban area ($26.464\pm 7.59ppb$) had about 2.8 times higher value than the downtown area ($9.284\pm 1.55ppb$). 2) The peak oxidant concentration of suburban area during the daytime is occured from noon to 5:00 P.M.. These patterns are similar to the classical patterns, but the peak Oxidant Concentration of downtown area in February was occured at 9:00A.M. 3) The overall level of nitrogen oxide pollution was much higher in downtown area than in suburban area. Two peaks of nitrogen oxide concentration occured at 10 A.M. and 12 midnight in downtown area. This observation agrees with the report that the air pollution is higher in the area where the pollution sources are concentrated. 4) The multiple correlation analysis for the oxidant and the other variables measured in February in downtown area showed close correlation with nitrogen oxide and ambient temprature. The multiple correlation coefficient of oxidant with nitrogen oxide was 0.872, and that with nitrogen oxide and temperature simultaneously was 0.903. The multiple correlation equation used for this study may be expressed as follows:

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.5
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• pp.477-491
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• 2014

This study was carried out to evaluate the concentration variations of volatile organic compounds (VOCs) in the office environments located in a large urban area with respect to seasonality, smoking status, types of ventilation and heating. Indoor air sampling was undertaken in 37 and 30 offices in Daegu city during summer and winter, respectively. The VOC samples were collected using adsorbent tubes, and were determined by thermal desorption coupled with GC/MS analysis. The analytical method was validated for repeatability, method detection limits (MDL), and duplication precision. A total of 34 VOCs of environmental concern were determined, including 15 aromatics and 19 halogenated hydrocarbons. Average concentrations of BTEX appeared to 1.91 ppb, 22.98 ppb, 3.44 ppb, and 3.70 ppb, respectively. These values were relatively higher levels than those measured at homes and outdoor roadsides reported by other researches. In general, the concentrations of VOCs were higher in winter than summer, in smoking offices than non-smoking offices, in forced ventilation type than natural ventilation type, and in combustion heating than non-combustion heating offices. However, such differences were not always significant at a level of 0.05 by statistical tests (t-test and/or Mann-Whitney test) with some exceptions for BTEX and styrene. This study demonstrated that smoking status, ventilation type and presence of combustion sources indoors could be important factors on the elevated concentrations of some VOCs in the office environment.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.2
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• pp.309-315
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• 2015

This study aimed to develop and validate an analytical method for ethyl carbamate (EC) in Maesilju. For accurate analysis of EC in Maesilju, an internal standard (d5-EC) and neutralization (pH=7) were performed. The limit of quantification (LOQ) was 3.65 ppb while the recovery rate ranged from 92.54% to 103.59%. Intra- and inter-day precision ranged from 0.87% to 1.99% and 2.67% to 5.64%, respectively. Maesilju samples comprised 10 homemade and five commercial ones. Samples contained EC at levels between 118.48 and 2,640.42 ppb. The average content of homemade Maesilju was higher than those of commercial ones. Based on manufacturers' labeling of commercial samples and information on homemade samples, various factors such as ingredients and soaking time of Maesil affected EC level in Maesilju. EC contents showed a positive correlation with age of Maesilju.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.468-474
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• 2020

The study was to determine the effects of diverse concentrations of T-2 toxin in broiler diet. Three hundred 1-day-old chicks with initial body weight of 46 ± 0.52 g were chosen and randomly assigned into five dietary treatments with 5 replicate cages and 12 broilers per cage for 42 d feeding trial. Dietary treatments were prepared with basal diets containing 0 (T₁), 50 (T₂), 100 (T₃), 150 (T₄), 200 (T₅) ppb T2-toxin. Significant results were observed in the decreased intake of feed, feed conversion ratio (FCR), body weight gain (BWG), level of serum protein, cholesterol and hemoglobulin of broilers in increased concentration of the T-2 toxin in diet (150 and 200 ppb) groups than control. Also, observed that the uric acid, serum glutamic pyruvic transferase (SGPT), serum glutamic oxaloacetic transferase (SGOT) and Heterophil/Lymphocyte (H/L) ratio value were significantly higher (p < 0.05) in groups T₄ and T₅ than control. However, the BWG, feed intake and FCR, as well blood biochemical profiles of serum protein, cholesterol, hemoglobulin, uric acid, SGPT, SGOT and H/L ratio in groups T₂ and T₃ were statistically similar to control diet of broilers. It was concluded that the results showed that no adverse effects on growth performance and blood biochemical parameters in broilers feed with T-2 toxin (50 and 100 ppb) during the entire trial.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.1
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• pp.104-114
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• 2015

Objectives: The purpose of this study is to investigate the atmospheric concentration of VOCs and the urinary concentration of t,t-MA, HA, MA in the industrial complex of Yeosu, South Jeolla Province. Methods: In order to study seasonal patterns of air concentration of VOCs, measurements were taken at five sampling sites around Yeosu from June 2013 to June 2014. Urinary metabolite excretionsfrom 671 subjects, exposure and comparison area were analyzed. Results: The average concentration of VOCs in the air was 1.53ppb for benzene, 0.73ppb for toluene, 0.22ppb for ethylbenzene, 0.52ppb for xylene and 0.12ppb for styrene. The concentration of benzene was somewhat higher than the year-average standard ($5{\mu}g/m^3$, about 1.5ppb) of the domestic air-environment criteria newly established in 2010.The metabolic concentration of VOCs in the urine of the entire sample was analyzed at $47.76{\mu}g/g\;cr.$, 213.07mg/g cr., and $290.09{\mu}g/g\;cr.$ for t,t-MA, HA, and MA, respectively. Compared with the average values for Korea as presented in the first basic survey of national environmental conservation ( $49.8{\mu}g/g\;cr.$ for t,t-MA, 0.17g/g cr. for HA, and 0.26mg/g cr. for MA), the metabolic concentrations of HA and MA in urine were higher than the average values. Conclusions: The concentration of VOCs in the air and urinary metabolites of the exposed and control areas showed that the concentrations of all substances were higher in the exposed area than in the control area.

• Applied Biological Chemistry
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• v.35 no.2
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• pp.115-121
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• 1992

Avermectin B1(abamectin) is an very effective acaricide/insecticide. Because it is applied at low rates, the resultant residue level would be quite low and this requires highly sensitive analytical method. In this study, three analytical methods for avermectin $B1_a$, were compared in view of detectability and sensitivity. The first analytical method was an HPLC method employing the fluorescence detection of avermectin. The second analytical technique to quantitate avermectin $B1_a$, and its photodegradative delta 8,9-isomer employed trifluoroacetic anhydride and 1-methylimidazole in DMF. The new method was the modification of trifluorescence method. The average recoveries of avermectin $B1_a$ for the concentration range from 1 and 10 ng/g in whole apple fruit by fluorescence method were 90.3% and 88.2% respectively. In trifluorescence method, the recoveries of the avermectin $B1_a$ and delta 8,9-isomer were 100.7% and 94.7% in concentration from 5 ng/g and 25 ng/g. The average recoveries of 5 ng and 25 ng/g in the newly modified method were 95.0, 99.0. 96.0, 92.8% in whole apple and soil respectively.

• Journal of the Korean earth science society
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• v.23 no.5
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• pp.424-435
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• 2002

This study analyzes the surface ozone and meteorological data in Daegu for a period from 1997 to 1999. It also investigates the meteorological characteristics of high ozone episodes. For this study the high ozone episode has been defined as a daily maximum ozone concentration higher than 100ppb in at least one station among six air quality monitoring stations in Daegu, Korea. The frequency of episodes is 13 days. The frequency is the highest in May and September. The average value of daily maximum ozone concentration is 81.6ppb, and 8-hour average ozone concentration is 58.6ppb for the high episodes. This shows that ozone pollution is continuous and wide-ranging in Daegu. The daily maximum ozone concentration is positively correlated to solar radiation and daily maximum temperature, but negatively correlated to relative humidity, wind speed and cloud amount. The maximal correlation coefficient to solar radiation is 0.45. The differences between high ozone episode day's daily mean meteorological value and monthly mean value are +1.58hPa for sea level pressure, +3.45${\circ}$C for maximum temperature, -5.69% for relative humidity, -0.46ms$^{-1}$ for wind speed, -1.79 for cloud amount, and +3.97MJm$^{-2}$ for solar radiation, respectively. This shows that strong solar radiation, low wind speed and no precipitation between 0700${\sim}$1100LST are favorite conditions for high ozone episodes. It is related to the morning stagnant condition.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1035-1039
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• 2010

For 65 national forest areas in 1993 to 2008, the ambient sulfur dioxide ($SO_2$) concentrations were measured monthly using passive samplers and compared to the those of urban areas in order to investigate the characteristics of temporal and spatial distribution. In the forest areas, annual average concentration of sulfur dioxide gradually decreased from the beginning year of monitoring to 1997 and then had no significant change, such as the annual trend in urban areas monitored by Ministry of Environment. For the monitoring term, average concentration of sulfur dioxide in the forest areas was 5.6ppb, which was lower than the 10.1ppb in the urban areas and the EC ecological standard level (7.6 ppb). Seasonally, both in forest areas and urban areas the monthly average concentrations were much higher in winter and spring due to much more heating fuel consumption, and lowest in summer. Regional comparison to other regions of Gyeongbuk and Gyeonggi province showed that the concentration of sulfur dioxide was the highest during year. A significant positive correlation between sulfur oxides' emissions and sulfur dioxide concentration by province was observed, reflecting that the size and proximity of sources of atmospheric sulfur oxides could be important factors in determination.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 2002.06a
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• pp.17-17
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• 2002