• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.189-192
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• 2009

Purpose: Autopipetting system is an efficient automated equipment pipetting patient samples and reagents for rapid and accurate test. However, it can cause carryover between high concentration sample and low concentration sample. We evaluated carryover contamination of TECAN freedom Evo 100 autopipetting system. Materials and Method: We studied carryover contamination of $\alpha$-fetoprotein (AFP) and carcinoembryonic antigen (CEA) test on TECAN freedom Evo 100 autopipetting system. Very low concentration control samples were pipetted for comparison to the contaminated very low concentration samples. Then, The contaminated very low concentration samples were pipetted following the high concentration samples were pipetted alternately. The difference of low concentration samples represents carryover. The target value to decide carryover was 1ppm (parts per million). Results: For AFP, the mean values of the uncontaminated control samples and the contaminated samples were less than 0.6 IU/mL (the l imit of detection (LoD)). Carryover did not occur even though the high concentration sample which value was 650000 IU/mL. For CEA, the values of the low concentration control samples and the contaminated samples were less than 0.2 ng/mL (LoD). Carryover did not occur even though the high concentration sample which value was 65,000 ng/mL. Conclusions: Sample carryover was not found on TECAN freedom Evo 100 autopipetting system for AFP, CEA. However, carryover is a potential problem with automated instruments and robotic pipetting systems. Therefore, Clinical laboratories must periodically verify carryover contamination for the accurate and confidential test results.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.51-56
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• 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
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• v.5 no.1
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• pp.71-88
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• 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
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• v.27 no.3
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• pp.146-155
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• 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 Journal of Engineering Geology
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• v.15 no.1
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• pp.29-39
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• 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%.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.178-184
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• 2005

Carry over contamination has been reduced in some systems by flushing the internal and external surfaces of the sample probe with copious amount of diluent. It between specimens should be kept as small as possible. A built-in, continuous-flow wash reservoir, which allows the simultaneous washing of the interior and exterior of the syringe needles, addresses this issue. In addition, residual contamination can further be prevented through the use of efficient needle rinsing procedures. In discrete systems with disposable reaction vessels and measuring cuvets, any carry over is entirely caused by the pipetting system. In analyzers with reuseable cuvets or flow cells, carry over may arise at every point through which high samples pass sequentially. Therefore, disposable sample probe tips can eliminate both the contamination of one sample by another inside the probe and the carry over of in specimen into the specimen in the cup. The results of the applicative carry over experiment studied on 21 items for total protein (TP), albumin (ALB), total bilirubin (TB), alkaline phosphatase (ALP), aspratate aminotranferase (AST), alanine aminotranferase (ALT), gamma glutamyl transferase (GGT), creatinine kinase (CK), lactic dehydrogenase (LD), creatnine (CRE), blood urea nitrogen (BUN), uric acid (UA), total cholesterol (TC), triglyceride (TG), glucose (GLU), amylase (AMY), calcium (CA), inorganic phosphorus (IP), sodium (Na), potassium (K), chloride (CL) tests in chematology were as follows. Evaluation of process performance less than 1% in all tests was very good, but a percentage of ALB, TP, TB, ALP, CRE, UA, TC, GLU, AMY, IP, K, Na, and CL was 0%, implying no carry over. Other tests were ALT(-0.08%), GGT(-0.09%), CK(0.08%), LD(0.06%), BUN(0.12%), TG (-0.06%), and CA(0.89%).

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.455-460
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• 2010

This study was carried out to find out any inherent problems occurring in the sampling and analytical procedures, and to suggest the relevant solutions to the problems. In addition, an optimal condition of clean-up process was developed, which was based on a method using silica glass column. As a result of experiments to test any artificial contamination of blank samples such as glassware and collection media, artifacts of DBP and DEHP appeared to be detected in various kinds of laboratory tools and apparatuses used in the sampling and analytical works. Therefore, it is necessary to investigate a degree of contamination before laboratory works by conducting a prior check any possible contaminations in all experimental tools and apparatus. It is also necessary to devise a method to avoid a tool, if possible, or to use a substitute of phthalate free. If the use of any plastic tool to cause contamination is inevitable, it should be properly corrected with a blank level, as is equally treated as the sample. The clean-up process demonstrated in this study can give us a significant benefit in terms of the quantity and quality of a target compound by GC/MS analysis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.E
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• pp.1-19
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• 1990

Abstract Over the last several decades, crop production in the United States increased largely due to the extensive use of animal waste and fertilizers as plant nutrient supplements, and pesticides for crops pests and weed control. Without the application of animal waste best management, the use of animal waste can result in nonpoint source pollution from agricultural land area. In order to increase nutrient levels and decrease contamination from agricultural lands, nonpoint source pollution is responsible for water quality degradation. Nonpoint source pollutants such as animal waste, ferilizers, and pesticides are transported primarily through runoff from agricultural areas. Nutrients, primarily nitrogen and phosphorus, can be a major water quality problem because they cause eutrophic algae growth. In 1985, it was presented that Watershed/Water Quality Monitoring for Evaluation BMP Effectiveness was implemented for Nomini Creek Watershed, located in Westmoreland County, Virginia. The watershed is predominantly agricultural and has an aerial extent of 1505 ha of land, with 43% under cropland, 54% under woodland, and 3% as homestead and roads. Rainfall data was collected at the watershed from raingages located at sites PNI through PN 7. Streams at stations QN I and QN2 were being measured with V-notch weirs. Water levels at the stream was measured using an FW-l Belfort (Friez FWl). The water quality monitoring system was designed to provide comprehensive assessment of the quality of storm runoff and baseflow as influenced by changes in landuse, agronomic, and cultural practices ill the watershed. As this study was concerned with the Nomini Creek Watershed, the separation of storm runoff and baseflow measured at QNI and QN2 was given by the master depletion curve method, and the loadings of baseflow and storm runoff for TN (Total Nitrogen) and TP (Total Phosphorus) were analyzed from 1987 through 1989. The results were studied for the best management practices to reduce contamination and loss of nutrients, (e.g., total nitrogen and total phosphorus) by nonpoint source pollution from agricultural lands.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.501-507
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• 2014

Norovirus (NoV) is a major cause of food poisoning outbreaks in Korea. Most NoV outbreaks originate from environmental contamination, but bivalves such as oysters are also important vectors. Oyster Crassostrea gigas contamination by NoV has been reported in Korea, but no quantitative analyses of NoV have been performed. We investigated the NoV concentration in 21 oyster samples from a Korean commercial oyster-growing area with confirmed fecal contamination from January to December 2012, using real-time reverse transcription-polymerase chain reaction. Additionally, we assessed the NoV concentration after heating to investigate the effects of heat treatment on NoV-infected oysters. In NoV-positive samples, the cycle threshold (Ct) values were 37.43-39.41 and 36.77-39.30, while viral concentrations were $8.97{\times}10^2-2.24{\times}10^2$ and $3.05{\times}10^2-7.47{\times}10^1$ copies/g for genogroups I and II, respectively. After heat treatment, NoV genogroup I decreased by 83.4%, 88.0%, 89.4% and 100% at $60^{\circ}C$, $68^{\circ}C$, $70^{\circ}C$, and $100^{\circ}C$, respectively, for 15 min, while genogroup II respectively decreased by 67.3%, 76.3%, 80.1%, and 89.8% under the same conditions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.930-940
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• 2013

We evaluated contamination with organic matter and trace metals by analyzing grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Ni, Cr, Mn, Hg, and As) in surface sediments at 28 stations around the Geum River estuary in July 2008. The surface sediments in the estuary were mainly composed of coarse sediment (sand and muddy sand), with mean grain size (Mz) ranging between $2-4{\O}$. The high concentrations of IL, COD, and trace metals were mainly found at stations in front of the Gusan outer port and industrial complex, and near the Seocheon coast with relatively fine sediments. In addition, the concentrations of IL and all trace metals, except Pb and As, showed good positive correlations with Mz, indicating that the concentrations of organic matter and trace metals were mainly dependent on sediment grain size. The concentrations of COD, AVS, and trace metals in most sediments did not exceed the sediment quality guideline (SQGs). Although the sediments in the study region are not polluted with organic matter and trace metals, there are many point sources of pollutants, such as Gusan port and industrial complex, Janghang refinery, and a thermoelectric power plant around the Geum River estuary. Thus, the management of coastal environments through periodic monitoring of organic matter and trace metals is required in the future.