• Title, Summary, Keyword: Contamination

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Applicability of Resistivity/Capacitance Measurement on CPT Module for Investigation of Subsurface Contamination (오염지반 조사를 위한 전기비저항/정전용량 측정콘의 적용성 평가)

  • Oh, Myoung-Hak;Kim, Yong-Sung;Yoo, Dong-Ju;Park, Jun-Boum
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.330-337
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    • 2006
  • Resistivity cone penetrometer test (RCPT) can be employed at a relatively low cost for delineation of subsurface contamination in situ, and then be supplemented with a minimum confirmatory sampling and laboratory testing program. While the resistivity measurement have potential to investigate the subsurface contamination, resistivity measurements alone will lead to some degree of ambiguity in the results. In this study, capacitance measurement was incorporated into the RCPT to overcome the ambiguity inherent in electrical resistivity measurements for delineating the subsurface contamination. This study is focused on verifying the applicability of resistivity and capacitance measurements on CPT module to provide information on contaminated subsurface by heavy metal and petroleum hydrocarbon. Laboratory model tests were performed to evaluate the sensitivity of the measured resistivity and relative capacitance on the water content and different types of contaminants. Test results show that simultaneous measurement of electrical resistivity and capacitance can give more reliable information on subsurface contamination.

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Reducing Fetal Contamination of Radiostronium by Water Soluble Chitosan

  • Kim, Young-Ho;Roh, Young-Bok;Kim, Kwang-Yoon;Bom, Hee-Seung;Kim, Jl-Yeul
    • Animal cells and systems
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    • v.1 no.2
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    • pp.337-340
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    • 1997
  • The purpose of this study is to evaluate whether water soluble chitosan, a natural nontoxic chelator, can reduce fetal contamination of radiostrontium in pregnant mice. Various forms of water soluble chitosans (10% or 1% powder, or 1% solution) were given to pregnant mice before or after contamination of 0.005 uCi/B.W(g) Sr-85. Transplacental transfer of Sr-85 to fetus was $6.8{\pm}2.7%$ of injected dose, when Sr-85 was administered at the 20th day of pregnancy. Fetal radioactivity was significantly reduced when mother mice were treated with water soluble chitosan before contamination of Sr-85. Water soluble chitosans of 10% or 1% powder, or 1% solution significantly reduced fetal retention of Sr-85 to $2.3{\pm}0.7%$, $2.7{\pm}0.8%$, and $2.0{\pm}0.9%$, respectively. However, fetal contamination was not reduced, when water soluble chitosans of 10% or 1% powder, or 1% solution were administered after maternal contamination of Sr-85. From these data we can conclude that water soluble chitosan could reduce fetal contamination of radiostrontium in pregnant mice, when given before the pregnant mice were exposed to radiostrontium.

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Detection of Microbial Contamination in Commercial Berries

  • Cho, Kyu-Bong
    • Biomedical Science Letters
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    • v.23 no.4
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    • pp.333-338
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    • 2017
  • This study was performed to assess microbial contamination of Aronia melanocarpa, blueberry, raspberry, and cranberry sold in several markets. We investigated total aerobic bacteria and detected foodborne bacteria by multiplex PCR from Aronia melanocarpa, blueberry, raspberry, and cranberry. Total aerobic bacteria of each sample showed mean 3.54 log CFU/g for Aronia melanocarpa, mean 1.90 log CFU/g for blueberry, and mean 1.40 log CFU/g for raspberry, but not detected in cranberry. Specially, Aronia melanocarpa contained high total aerobic bacteria contamination among various berries and contamination level reached 4.17 log CFU/g in sample 5. To evaluate the effect of distribution conditions, we also investigated total aerobic bacteria of various berries. Total aerobic bacteria showed mean 2.89 log CFU/g for berries in refrigerated distribution and 1.40 log CFU/g in frozen distribution, but not in dry distribution. For assessment of foodborne bacteria contamination, we conducted PCR with multiplex primers of E. coli O157, S. aureus, B. cereus, V. parahaemolyticus, L. monocytogenes, Y. enterocolitica, Salmonella spp., Shigella spp. Among these foodborne bacteria, B. cereus was amplified in Aronia melanocarpa in sample 4 and blueberry in sample 1, 2, 3, and 5. The result of quantitative analysis of B. cereus contamination showed 4.08 log CFU/g of Aronia melanocarpa in sample 4 and higher contamination rate 4.07 log CFU/g of blueberry in sample 3. These results suggest that strict food safety control in harvest and distribution of various berries is necessary to prevent foodborne disease and improve microbiological safety.

Study on the soil contamination characteristics according to the functions of the returned U.S. military base (반환미군기지 기능별 토양오염특성에 관한 연구)

  • Oh, Chang-Gyu
    • Journal of Environmental Impact Assessment
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    • v.22 no.5
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    • pp.481-489
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    • 2013
  • There are U.S. troops with a force about 290,000 strong stationed all around the world, approximately 150 countries. Among the troops, USFK has performed principal part with its stationing for 50 years against the military threat of North Korea. However, as a result of an investigation made into environmental contamination of several bases which were restituted from US to ROK by the Land Partnership Plan in the process of relocation of USFK, it was found that the area was contaminated by not only TPH and BTEX caused by diesel fuel and JP-8 but also various heavy metal over the standard level according to the operations of corps. Among these bases, 4 corps, each of which has different duties and function, were chosen to be analyzed for the characteristics and degrees of soil contamination. Fisrt of all, in armored camp the soil was contaminated by TPH and heavy metal (Zn, Ni, Pb) due to the repairing activities of tracked vehicles and shooting exercises. In army aviation camp, the soil was contaminated by TPH, BTEX and heavy metal (Zn, Cd) due to repairing activities of aircrafts. Also, in engineer camp there was contaminated area polluted by TPH and heavy metal (Zn, Pb) caused by open-air storage of various construction materials and TPH, BTEX and heavy metal (Zn, Pb, Cu) contamination of aircraft shooting area in shooting range camp were detected. Managing environment will be more effective when we identify the contaminative characteristics and take necessary measures in advance.

Effects of ionized calcium on microbial cross-contamination in surface of carcass via slaughter process of chickens (이온화칼슘이 도계과정 중 도체표면의 미생물 교차오염에 미치는 영향)

  • Park, B.S.;Jin, J.Y.
    • Journal of the Korean Applied Science and Technology
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    • v.33 no.4
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    • pp.813-823
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    • 2016
  • The purpose of this study was to investigate the effects of ionized calcium treatment on total bacterial cross-contamination of chicken carcass surface in the slaughtering process. The growth of Escherichia coli was strongly inhibited in a medium prepared by using a 0.5% ionized calcium solution. The total bacterial cross-contamination of chicken carcass surface and the scalding water was significantly increased as the number of scalding was increased (p<0.05). The total bacterial cross-contamination of chicken carcass surface reached a plateau without a further increase as scalding was performed consecutively for 10 or more times. The total bacterial cross-contamination of the scalding water was significantly increased as the number of scalding was increased (p<0.05). The total bacterial cross-contamination of chicken carcass surface of the chickens raised on a floor type farm was significantly higher than that of the chickens raised in a battery cages (p<0.05). The total bacterial cross-contamination of chicken carcass surface of the chickens raised on a floor type farm was significantly lower in the 0.5% ionized calcium solution treatment group than in the control group (p<0.05).

An Off-site Screening Process for the Public in Radiation Emergencies and Disasters

  • Yoon, Seokwon;HA, Wi-Ho;Jin, Young-Woo
    • Journal of Radiation Protection and Research
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    • v.41 no.3
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    • pp.301-309
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    • 2016
  • Background: A contamination screening process for the local population in radiation emergencies is discussed. Materials and Methods: We present an overview of the relevant Korean governmental regulations that underpin the development of an effective response system. Moreover, case studies of foreign countries responding to mass casualties are presented, and indicate that responses should be able to handle a large demand for contamination screening of the local public as well as screening of the immediate victims of the incident. Results and Discussion: We propose operating procedures for an off-site contamination screening post operated by the local government for members of the public who have not been directly harmed in the accident. In order to devise screening categories, sorting strategies assessing contamination and exposure are discussed, as well as a psychological response system. Conclusion: This study will lead to the effective operation of contamination screening clinics if an accident occurs. Furthermore, the role of contamination screening clinics in the overall context of the radiation emergency treatment system should be clearly established.

Experimental investigation of effects of sand contamination on strain modulus of railway ballast

  • Kian, Ali R. Tolou;Zakeri, Jabbar A.;Sadeghi, Javad
    • Geomechanics and Engineering
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    • v.14 no.6
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    • pp.563-570
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    • 2018
  • Ballast layer has an important role in vertical stiffness and stability of railway track. In most of the Middle East countries and some of the Asian ones, significant parts of railway lines pass through desert areas where the track (particularly ballast layer) is contaminated with sands. Despite considerable number of derailments reported in the sand contaminated tracks, there is a lack of sufficient studies on the influences of sand contamination on the ballast vertical stiffness as the main indicator of track stability. Addressing this limitation, the effects of sand contamination on the mechanical behavior of ballast were experimentally investigated. For this purpose, laboratory tests (plate load test) on ballast samples with different levels of sand contamination were carried out. The results obtained were analyzed leading to derive mathematical expressions for the strain modulus ($E_V$) as a function of the ballast level of contamination. The $E_V$ was used as an index for evaluation of the load-deformation characteristics and bearing capacity of track substructure. The critical limit of sand contamination, after which the $E_V$ of the ballast reduces drastically, was obtained. It was shown that the obtained research results improve the current track maintenance approach by providing key guides for the optimization of ballast maintenance planning (the timing of ballast cleaning or renewal).

A Study on the Relationship Between Length of Time and Contamination in Open Intravenous Solutions (정맥주사용 수액의 개방후 시간경과에 따른 오염도에 관한 실험연구)

  • 김일원
    • Journal of Korean Academy of Nursing
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    • v.16 no.1
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    • pp.67-80
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    • 1986
  • The use of intravenous solutions for fluid replacement has become an integral part of patient care, This widespread use of intravenous solutions has increased the risk of contamination that can lead to septicemia and phlebitis. The literature regarding contamination of in use intravenous solutions recommends a standard 24-hour time limit on the use of these fluids. But the desings of these studies did not incorporate a time variable related to contamination. In other studies, however, time was a manipulated variable: but data regarding the onset of contamination were conflicting. Because published reports conflict with regard to a time standard related to the use of intravenous therapy, additional empirical data are needed upon which to base the standards of care regulating use of intravenous therapy. This study investigated rate of contamination in simulated in-use intravenous solutions to obtain data from which to recomend a standard time period for the administration of intravenous solutions. In this study samples were drawn from 60 bottles of 5% D/W solution at predetermined time intervals over 48 hours and samples were inoculated to Thio-glychollate Broth. After 10 days' culturing in that Broth, samples were cultured on blood agar plates for 18∼48 hours to determine the rate of contamination. was found at all time Period, regardless of the presence or absence of nurse's gloving in the preparation of fluids, the location in which the experimentations were performed, the contamination level of surrounding air, or the length of time during which solutions were opened. Data from this study support the use of a 48-hour time period on which to base the standard involved in ready-to-use simple intravenous solutions without additives. In emergency departments and critical care areas where intravenous solutions are prepared in advance, the suggested time standard supported by the data generated from this study is 48 hours, not 24 hour. Data from this study support a 24-hour time standard for changing in-use intravenous solutions when the contamination results from the manipulation of intravenous infusion system by hospital personnel, or from some other exogenous sources during administration. Because contamination that does occur within 48 hours in intravenous solutions must be introduced from some exogenous sources, further empirical studies based on the identification of sources of contamination and factors that affect the rate of contamination, are needed to investigate the currently employed standard of intravenous therapy and to provide the patient with more efficient and safer intravenous thereapy.

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A Study on the Contamination of Solution with Suction used in Tracheostomy Patients (기관지절개술 환자의 흡인시 사용하는 용액의 오염수준 변화 연구)

  • Lim Yun-Hee;Yu Kwang Soo
    • Journal of Korean Public Health Nursing
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    • v.12 no.2
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    • pp.185-200
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    • 1998
  • It has been contributed to public health that the hospital has multiplied in the aspect of number and has been a large size with development of modern medical science, meanwhile the problem of hospital infection is coming out seriously. Respiratory hospital infection among hospital infections develops, very commonly from patients having taken the operation of intubation or tracheostomy, which results from a big factor that the infection developed from medical appliances used for respiration aids, contamination of solution and infection of medical staff. This study is separated into four steps-the time to use normal saline and distillation water for storaging catheter which are the cause of the infection of solution to store distillation water and catheter, not to say the catheter used when the patient who should get tracheostomy operation takes suction. The purpose of this study is to offer the basic data which are needed to check contamination degree as time goes by and nurse intervention and grope for a new nursing intervention. The target of this study is hospitalized 1D an intensive care unit having 700 sickbeds which is located in IKSAN city and it targeted patients before 7 days passed after an operaion of a tracheostormy. Materials collected were analyzed by SPSS PC+ figures program. The result of this study were as follows ; 1. The gradual contamination levels of the normal saline used In suction are showing that colony increase in proportion to the length of time. 2. while colony increases in normal saline with the lapse of time. distillation water mixed with 5cc of potadine did not show any sign of the formation of colony from its preparation until it was used for 8 hours. 3. Such variables as the period of intubation insertion. the length of hospitalization in I.C.U. the age and the level of contamination of normal saline have no inter-relationship. Therefore. as the length of normal saline used In suction. the contamination level increases with the excelleration of the contamination speed. 4. Regarding the number of suction and the contamination level of the normal saline. We can observe correlation contamination level in the 3 step of suction(mean value:13.4) and the saline which was used for one hours(r=0.702. P=0.00l). four hours(r=0.694. P=0.00l). eight hours(r=0.488. P=0.029). Further we can observe contamination in the 4 step of suction (mean value: 17 .8) well as saline used for eight hours; [for one hours (r=0.64l. P=0.002). four hours (r=0.670. P=0.00l). eight hours (r=0.57 4. P=0.008)]. Thesedays clinics use normal saline by changing it. three times a day. however. the timing of saline change and the current suction methoed should be changed given the one hour used normal saline contamination number 79.850. Regarding the number of suction and the contamination lend of the normal saline.

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Clinical Characteristics Associated with Blood Culture Contamination in Neonates (신생아에서 혈액 배양 오염과 관련된 임상적 특징)

  • Jung, Min Young;Son, Ok Sung;Hong, Yoo Rha;Oh, Chi Eun
    • Pediatric Infection and Vaccine
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    • v.22 no.3
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    • pp.147-153
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    • 2015
  • Purpose: This study was aimed to investigate the contamination rates of blood culture in a neonatal intensive care unit (NICU) and to examine the clinical characteristics related to the contamination. Methods: Eight hundred thirty cases of blood culture performed from March 2013 to February 2014 were analyzed. We evaluated the contamination rates of blood culture by blood sampling sites and compared the clinical characteristics such as real name system and body weights of the contaminated cases and those of non-contaminated ones. The clinical characteristics were retrospectively reviewed by medical records. Results: The overall contamination rate was 3.6% (30/830). The contamination rates by blood sampling sites were as follows: peripheral vein 15.6% (10/64), peripheral artery 2.6% (20/759), and umbilical arterial catheter 0% (0/7). There was no difference in the contamination rates between cases with and without real name system (P=0.484). However, there were significant differences in the contamination rates by the physicians who performed the culture (P=0.038) and body weight (<1,000 g vs. ${\geq}1,000g$) at the time of blood culture (P<0.001). Conclusions: These results suggest that neonates with a body weight less than 1,000 g have more risks of the contamination of blood culture. Furthermore, there is a necessity to provide blood culture performers with active feedbacks and individualized education plans that can help diminish blood culture contamination rates. Prospective studies in a systematic manner that can be applied in actual clinical settings are needed in order to figure out factors that can diminish the contamination rates of blood culture in NICU.