• Journal of the Korea Convergence Society
• /
• v.11 no.1
• /
• pp.51-56
• /
• 2020

It is going to select one X-ray generating device for diagnosis in a radiography laboratory at K university in Gangwon-do to detect bacteria on the surface contamination of tables, IP cassettes, and lead gowns for medical radiation shielding and to inform students of the need for proper disinfection control and hand hygiene. Then disinfection was carried out with tissue, tissue cleaner and 70% alchol and immediately collected with sterile cotton swabs to assess the contamination distribution status and disinfection effects of the surface. The results of measuring the degree of contamination on the surface showed that the largest number of bacteria were detected in Apron, and the evaluation of the disinfection effects according to surface contamination showed a noticeable effect at 70% Alcohol in IP Cassette, and the disinfection effect was the same for Apron. Therefore, in order to prevent bacterial infections among students, basic hand washing and regular disinfection should be performed before the practice to prevent infection.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.5 no.1
• /
• pp.71-88
• /
• 2003

The DRASTIC system is widely used for assessing regional groundwater pollution susceptibility by using hydrogeological factors such as depth to water, net recharge, aquifer media, soil media, topography, vadose zone media, hydraulic conductivity. This study is providing Modified Drastic Model to which lineament density, land use, influence of groundwater drawdown caused by tunnel excavation are added as additional factors using geographic information system, and then to evaluate groundwater contamination potential of ${\bigcirc}{\bigcirc}$ area. For statistical analysis, vector coverage per each factor is converted to grid layer and after each correlation coefficient between factors, covariance, variance, eigenvalue and eigenvector by principal component analysis of 3 direction, are calculated, correlation between factors is analyzed. Also after correlation coefficients between general DRASTIC layer and rated lineament density layer, between general DRASTIC layer and rated land use layer, between general DRASTIC layer and rated tunnel excavation influence layer are calculated, final modified DRASTIC model is constructed by using them with each weighting. When modified DRASTIC model was compared with general DRASTIC model, contamination potential in modified DRASTIC model is fairly detailed and consequently, vulnerable area which has high contamination potential could be presented concretly.

• Progress in Medical Physics
• /
• v.27 no.3
• /
• pp.146-155
• /
• 2016

As the probability of exposure to radiation increases due to an increase in the use of radioisotopes and radiation generators, the importance of a radiation safety management field is being highlighted. We intend to help radiation workers with exposure management by identifying the degree of radiation exposure and contamination to determine an efficient method of radiation safety management. The personal exposure doses of the radiation workers at the Korea Institute of Radiological & Medical Sciences measured every quarter during a five-year period from Jan. 1, 2011 till Dec. 31, 2015 were analyzed using a TLD (thermoluminescence dosimeter). The spatial dose rates of radiation-controlled areas were measured using a portable radioscope, and the level of surface contamination was measured at weekly intervals using a piece of smear paper and a low background alpha/beta counter. Though the averages of the depth doses and the surface doses in 2012 increased from those in 2011 by about 14%, the averages were shown to have decreased every year after that. The exposure dose of 27 mSv in 2012 increased from that in 2011 in radiopharmaceutical laboratories and, in the case of the spatial dose rate, the rate of decrease in 2012 was shown to be similar to the annual trend of the whole institute. In the case of the surface contamination level, as the remaining radiation-controlled area with the exception of the I-131 treatment ward showed a low value less than $1.0kBq/m^2$, the annual trend of the I-131 treatment ward was shown to be similar to that of the entire institute. In conclusion, continuous attention should be paid to dose monitoring of the radiation-controlled areas where unsealed sources are handled and the workers therein.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.12 no.1
• /
• pp.3-12
• /
• 2008

Purpose: Contaminated clothes and bedclothes of patients by mouth or with excrement are produced after Radioisotope $^{131}I$ treatment. In this paper, patient's clothes and bedclothes contaminated by radioactivity measured and radioactive waste wish to calculate optimum storage period. Material and Methods: The whole area of patients' clothes and bedclothes measured 70 patients, 12 males and 58 females, who had radioisotope $^{131}I$ therapy between August 2005 and February 2006. Assuming contamination is evenly distributed, the radioscope used to measure up to social toleration level at 7 day intervals. Results: Each optimum storage period of control group of 60 case and non control group of 10 case were average $44{\pm}16$ days and $32{\pm}13$ days. Decontamination effect of surface contamination for radioactive waste was average $83.66{\pm}15.15%$. Conclusion: It is important that classify radioactive waste according to difference of surface contamination. Result of this research, handling radioactive waste in optimum storage period may be useful.

• Korean Journal of Food Science and Technology
• /
• v.41 no.3
• /
• pp.334-338
• /
• 2009

To determine the contamination status of Sushi fish and rice, seventy-nine samples of Sushi were collected from wholesale markets and Japanese restaurants within the Seoul area and subsequently analyzed for food-borne pathogens. Total aerobic counts ranged from 4 to 6 log CFU/g for the sliced raw fish, and from 3 to 5 log CFU/g for the boiled rice. Higher levels of contamination were detected in bream and shrimp Sushi versus other types. Coliform counts of 3-4 log CFU/g were detected in the sliced raw fish, whereas levels in the boiled rice were one log CFU/g lower compared to the raw fish. The raw Sushi fish had higher amounts of contamination than the boiled rice, however, E.coli was not detected. The prevalence rates of pathogens, namely Staphylococcus aureus and Bacillus cereus, in the raw fish were 17% and 10%, respectively. Similarly, the prevalence rates in the boiled rice were 11% and 8% for S. aureus and B.cereus, respectively. Salmonella and Listeria monocytogenes were also detected; however, other pathogens such as Vibrio parahaemolyticus, Clostridium perfrigens, and Yersinia enterocolitica were not detected. Among the high contaminating pathogens, B.cereus was found in 13% of samples from the wholesale markets, while S.aureus was found in 30% of samples from the Japanese restaurants. Therefore, these data suggest that the primary microbial hazard factors for Sushi are S. aureus and B. cereus, in addition to V. parahaemolyticus, and further risk assessments should focus on those pathogens.

• Journal of Soil and Groundwater Environment
• /
• v.10 no.2
• /
• pp.28-34
• /
• 2005

The aim of this article is to assess the application characteristics of the site by remediating oil-contaminated area using DSB (Deep-site Biopile) system. In the contaminated area, the soil was composed of penetrable sand and the leaked oil was spread widely (total 7,201 cubic meters) through 2.5 meter deep underground water flow. DSB system was operated for 30 minutes intervals for 24 hours in a day (30 minutes opεration and 30 minutes stop). To check contamination level change in the contaminated area after DSB system was operated, samples were taken. The result from the site shows that BTEX/TPH contamination level was dropped 50% after 30-day operation of DSB system, and that contamination level was dropped below contamination level check standard after 165 days and the remediation was completed. Unlike traditional biological remediation methods DSB system could efficiently process soil and water which were contaminated by high levels of oil compounds.

• Journal of Soil and Groundwater Environment
• /
• v.8 no.2
• /
• pp.9-18
• /
• 2003

Sampling of waters from each stage of treatment system (Successive Alkalinity Producing System; SAPS), tailings seepage, and spring near the Hanchang coal mine of Kangwon Province were carried out seasonally and analyzed to evaluate the source and possible path of groundwater contamination by acid mine drainage (AM). Sulfur isotope compositions were measured to identify the origin of groundwater contaminations and the sulfate reduction processes in the SAPS. Low pH and high metal concentration of spring water indicates possibility of the groundwater contamination by AMD. Removal efficiency of acidity of the SAPS was 18.17 g/$\textrm{m}^2$/day on an average and the metal removal efficiency was almost 100%, which was higher than those of other treatment systems. However, no appreciable decrease of sulfur content and almost similar sulfur isotope compositions of water from each stage of the treatment system may suggest incomplete or very poor sulfate reduction by sulfate reducing bacteria. Chemical and sulfur isotope compositions showed that spring water was contaminated by seepage from mine tailings. And seepage of stonewall, a part of treatment system was affected by both tailings seepage and mine adit drainage. In this study site, the treatment system was constructed for the only AMD from mine adit not for tailings seepages, which resulted in the groundwater contamination from tailing seepages. Similar situation is expected in other abandoned coal mine areas.

• The Journal of Engineering Geology
• /
• v.15 no.1
• /
• pp.29-39
• /
• 2005

For detecting a ground contamination survey, soil sampling method have been used a drilling or coring technique in general. However these methods are very difficult to systematically real-time monitoring of variation of contamination degree in field. ]'n this research frequency Domain Reflectometry (FDR) system was suggested and carried out to experimental approaches for determination of oil contamination on surface and underground. Experimental method using FDR method was discussed with feasibility of measurement in the laboratory column test. It is determined to degree of oil contamination due to response of dielectric constant re-lated with volumetric water content(θ/sub w/) and volumetric oil content( θ/sub al/ ) of saturated and unsaturated soil media. And physical properties such as effective porosity and oil residual ratio of saturated soil media were also measured through real-time monitoring works using installed FDR measurement sensors, which are defected characteristics of oil movement in the saturated soil media under the soil column tests. In the results of these experiments, a range of effective porosity was estimated to about 0.35 compared with initial porosity 0.40 of manufactured saturated soil media, which is also calculated to about 87.5% to the ratio of initial porosity to effective porosity. Finally oil residual ratio which is compared with volumetric water content and volumetric oil content was calculated about 62.5%.

• Journal of Food Hygiene and Safety
• /
• v.22 no.2
• /
• pp.105-109
• /
• 2007

This study monitored and compared the contamination levels of total aerobic bacteria, coliform groups and S. aureus of 16 Shrimp Jeotgal (Salt Fermented Shrimp) products from 3 traditional markets (TM), 3 department stores (DS) and 3 super markets (SM) located on seoul, Korea. Moreover this study was carried out to survey the concentrations of NaCl and heavy metal (lead; Pb) of the Shrimp Jeotgal. The contamination levels of total aerobic bacteria in the Shrimp Jeotgai were $3.35log_{10}CFU/g$ as a mean and $3.71log_{10}CFU/g$ for TM, $3.16log_{10}CFU/g\;for\;DS,\;2.84log_{10}CFU/g$ for SM. The coliform groups were contaminated in 50% of Shrimp Jeotgal and it means that the hygienic control is needed urgently. S. aureus were not detected in every sample. The levels of NaCl were between 17.9 and 28.5%. Heavy metal (lead; Pb) was detected in only 1 product at the level of 0.02 ppm out of 16 products. Although microbiological contamination levels of Shrimp Jeotgal were not much high, hygienic management like HACCP is thought to be needed for the production of Shrimp Jeotgal in traditional market.

• Journal of Food Hygiene and Safety
• /
• v.8 no.4
• /
• pp.241-249
• /
• 1993

This study was performed to investigate the remainity of synthetic surfactant (LAS) by HPLC and the microbial contamination on stainless steel dishes. For the maintenance and the improvement of school lunch program's safety, the remainity of synthetic surfactants (LAS) on stainless steel dishes washed with auto dishwasher was investigated by HPLC, and the microbial contamination on same dishes was surveyed. The results were as follows: (1) The remainity of synthetic surfactant (LAS) a) The residue of LAS was very small because of the repeated washing of dishes by strong pressurized water. b) The remainity range of LAS on stainless steel dishes was 2.1~7.2 $\mu\textrm{g}$/dish. The remainity of general surfactants was higher in cold water then warm water. The amount of residual general surfatants was 5.95 $\mu\textrm{g}$/dish in cold water, and 2.95 $\mu\textrm{g}$/dish in warm water. There was no difference of the remainity of special surfactants by water temperature. The amount of residual surfactants was 3.9 $\mu\textrm{g}$/dish. c) There was no difference of residue amount by washing times. (2) The microbial contamination after washing with general surfactants. 1) The mean MPN of E. coli was 203(53~345) on 1 hr, 19(6~28) on 2 hrs, in cold water, and 1100(only 1 dish of 1 school) on 1 hr, 24(6~42) on 2hrs. 2) After washing with general surgactants the mean of contamination by general microbials was 956(25~2300)on 1 hr, 694(45~2500) on 2 hrs. in cold water and 803(5~2300) on 1 hr, 671(5~2500)on 2 hrs. After washing with special surfactants the mean of contamination by general microbials was 788(136~2900) on 1 hr, 1122(15~3000) on 2 hrs, in cold water and 537(5~2000) on 1 hr, 88(15~150) on 2 hrs in warm water. (3) Like the results of this study, the good washing methods of stainless steel dishes for school luch program were as follows. First, for washing stainless steel dishes, the use of special surfactants was recommended at 30~4$0^{\circ}C$ water. Second, at 7$0^{\circ}C$ water, the rinsing of dishes was recommended. Third, the final rinsing at 8$0^{\circ}C$ combined with simple disinfection and dry was recommended.