• Title/Summary/Keyword: Hexavalent Chromium

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Cancer Mortality and Incidence in Cement Industry Workers in Korea

  • Koh, Dong-Hee;Kim, Tae-Woo;Jang, Seung-Hee;Ryu, Hyang-Woo
    • Safety and Health at Work
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    • v.2 no.3
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    • pp.243-249
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    • 2011
  • Objectives: Cement contains hexavalent chromium, which is a human carcinogen. However, its effect on cancer seems inconclusive in epidemiologic studies. The aim of this retrospective cohort study was to elucidate the association between dust exposure in the cement industry and cancer occurrence. Methods: The cohorts consisted of male workers in 6 Portland cement factories in Korea. Study subjects were classified into five groups by job: quarry, production, maintenance, laboratory, and office work. Cancer mortality and incidence in workers were observed from 1992 to 2007 and 1997-2005, respectively. Standardized mortality ratios and standardized incidence ratios were calculated according to the five job classifications. Results: There was an increased standardized incidence ratio for stomach cancer of 1.56 (27/17.36, 95% confidence interval: 1.02-2.26) in production workers. The standardized mortality ratio for lung cancer increased in production workers. However, was not statistically significant. Conclusion: Our result suggests a potential association between cement exposure and stomach cancer. Hexavalent chromium contained in cement might be a causative carcinogen.

Effects of Temperatures and Conditioning Methods on Fixation of CCA-Type Band CCFZ Preservatives in Treated Wood (양생온도(養生溫度)와 방법(方法)이 CCA-Tyoe B와 CCFZ 방부처리재(防腐處理材)의 양생(養生)에 미치는 영향(影響))

  • Kim, Gyu-Hyeok;Ra, Jong-Bum
    • Journal of the Korean Wood Science and Technology
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    • v.23 no.4
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    • pp.33-38
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    • 1995
  • The rates of fixation of CCA-Type B and CCFZ in blocks of radiata pine sapwood were compared at various temperatures and conditioning methods (drying and nondrying conditioning). Also the time required to proper fixation of preservative components in the treated wood was estimated. Fixation was monitored by the rates of depletion of free hexavalent chromium in the cell lumens in the teated blocks. The rate of preservative fixation in wood was highly temperature dependent. The fixation rate was considerably accelerated by means of heating and complete fixation of hexavalent chromium was achieved within about 12 hours by heating at $60^{\circ}C$. The moisture content of treated wood during fixation apparently played an important role in the fixation process. The fixation rate of treated wood conditioned in nondrying conditions was much more faster than that of treated wood conditioned in drying conditions. particularly when the moisture content of treated wood was below fiber saturation point. Time required to full fixation could be predicted successfully using the fixation temperatures applied since the correlation between the fixation temperature and the fixation time was excellent. regardless of conditioning methods.

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Monte Calro Analysis of Cancer Risk from Airborne Trace Metals (대기중 미량금속의 발암 위해도에 대한 몬테 카를로 분석)

  • 장미숙;이진홍
    • Journal of Korean Society for Atmospheric Environment
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    • v.18 no.6
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    • pp.465-474
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    • 2002
  • In order to reflect variability due to exposure factors as well as to assess uncertainty associated with cancer risk posed by airborne trace metals, a Monte Calro analysis has been made in this study. Input parameters for Monte Carlo analysis were developed or adjusted using body weight, lifetime, and exposure frequency of Koreans. Ambient distributions of toxic metals were founded to be lognormal distributions for most of them using goodness-of-fit tests. Thus, the 95% UCL and 95% LCL of carcinogenic metals were estimated by H-statistic method for lognormal distribution, respectively. The results of Monte Carlo analysis of 95% UCL showed that the 95th percentile risks for men and women were 1.2 and 1.1 times higher than an acceptable risk of 10$^{-5}$ , respectively. The probabilities which those risks exceed the acceptable risk were estimated to be 8% and 6%, respectively, while to be 95% and 94%, respectively on the basis of the minimum acceptable risk of 10$^{-6}$ , respectively. Approximately 90% of total cancer risk came from human carcinogens such as arsenic and hexavalent chromium. Therefore, it is necessary to properly manage both arsenic and hexavalent chromium emissions in the study area.

Comparative Risk Assessment Methodology: An Application to Air Pollution (비교 위험도 평가 방법의 대기 오염에 대한 적용 연구)

  • Lee, Jin-Hong
    • Journal of Korean Society for Atmospheric Environment
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    • v.8 no.2
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    • pp.100-104
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    • 1992
  • The research in this paper centers on a comparative risk assessment for nearby air pollution by carcinogenic metal emission from municipal solid waste incinerators. If a substance is identified as a potential human carcinogen, the carcinogenicity may be related to the chemical form of a substance and the route of exposure. This type of information with regard to carcinogenic uncertainty is incorporated into hazard quantification. In addition to the dioxin emission, the metal emission from municipal solid waste incineration is found to be a major contributor to human cancer risk via the inhalation route. The magnitude of risk by metals is about 5 times greater than that of risk by dioxins. Hexavalent form of chromium and cadmium compounds are major contributors to cancer risk from metal emission. In addition, hexavalent chromium is known to be human carcinogen while 2,3,7,8-TCDD is known to be only probable human carcinogen.

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Removal of Hexavalent Chromium by using Biomass (바이오매스를 이용한 6가 크롬의 제거)

  • Park, Donghee;Park, Jong Moon
    • Korean Chemical Engineering Research
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    • v.44 no.2
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    • pp.107-113
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    • 2006
  • Not only Cr(VI) is very toxic, but also it is a major pollutant in soil and groundwater. Thus Cr(VI)-containing wastewater must be treated before being discharged into the environments. Recently, biosorption technology using abundant biomass has been considered as an innovative one for removing Cr(VI) from aqueous solution. In this review article, current research and future works on Cr(VI) biosorption were widely described. Particularly, the removal mechanism of Cr(VI) by biomass was described in detail, which has been misunderstood by many researchers until now.