• Title/Summary/Keyword: specific hazardous substances

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Adsorption Characteristics of Heavy Metal and VOCs of Pyrolysis Char from Organic Waste Sludge (유기성 폐슬러지의 열분해 차르에 대한 중금속 및 VOCs 흡착특성)

  • Park, Sang-Sook;Kang, Hwa-Young
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.2
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    • pp.130-137
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    • 2005
  • This research programme include investigation of the adsorption behavior of heavy metals and VOCs by Pyrolysis char for using landfill cover material. The volatile potions in the sludge gasified during the pyrolysis period and gave birth to porosity throughout the matrix. The result of the ad/desorption experiment of nitrogen to find out the formation of some pore by the gasification of the volatile matter, we can certify that the pyrolysis char($14.56\;m^2/g$) has increased twice more than the organic wasted sludge($6.68\;m^2/g$) in specific surface area. The pyrolysis char has the adsorption characteristic of medium type of Type II and V in BDDT classification, and showed a little micro pore. In the adsorption experiment of ethylbenzene and toluene, as a result of applying the Freundlich adsorption isotherms, the pyrolysis char was higher in the adsorptivity of ethylbenzene and toluene than the granite and the organic wasted sludge. The results of the heavy metal adsorption test for the char indicated that it had some ability of adsorption. It is suggest that pyrolysis char has some advantages for utilizing as landfill covers because the pyrolysis char can adsorb/absorb hazardous substances from the landfill sites and inhibit the ground water and soil contamination.

Exposure Characteristics of Construction Painters to Organic Solvents

  • Park, Hyunhee;Park, Hae Dong;Jang, Jae-Kil
    • Safety and Health at Work
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    • v.7 no.1
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    • pp.63-71
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    • 2016
  • Background: Construction painters have not been studied well in terms of their hazards exposure. The objective of this study was to evaluate the exposure levels of total volatile organic compounds (TVOCs) for painters in the construction industry. Methods: Activity-specific personal air samplings were carried out in three waterproofing activities [polyurethane (PU), asphalt, and cement mortar] and three painting activities (epoxy, oil based, and water based) by using organic-vapor-monitor passive-sampling devices. Gas chromatograph with flame ionization detector could be used for identifying and quantifying individual organic chemicals. The levels of TVOCs, by summing up 15 targeted substances, were expressed in exposure-index (EI) values. Results: As arithmetic means in the order of concentration levels, the EIs of TVOCs in waterproofing works were 10.77, 2.42, 1.78, 1.68, 0.47, 0.07, and none detected (ND) for indoor PU-primer task, outdoor PU-primer task, outdoor PU-resin task, indoor PU-resin task, asphalt-primer task, asphalt-adhesive task, and cement-mortar task, respectively. The highest EI for painting works was 5.61 for indoor epoxyprimer task, followed by indoor epoxy-resin task (2.03), outdoor oil-based-spray-paint task (1.65), outdoor water-based-paint task (0.66), and indoor oil-based-paint task (0.15). Assuming that the operations were carried out continuously for 8 hours without breaks and by using the arithmetic means of EIs for each of the 12 tasks in this study, 58.3% (7 out of 12) exceeded the exposure limit of 100% (EI > 1.0), while 8.3% (1 out of 12) was in 50e100% of exposure limit (0.5 > EI > 1.0), and 4 tasks out of 12 were located in less than 50% of the limit range (EI < 0.5). Conclusion: From this study, we recognized that construction painters are exposed to various solvents, including carcinogens and reproductive toxins, and the levels of TVOC concentration in many of the painting tasks exceeded the exposure limits. Construction workers need to be protected from chemical agents during their painting works by using personal protective devices and/or work practice measures. Additional studies should focus on the exposure assessment of other hazards for construction workers, in order to identify high-risk tasks and to improve hazardous work environments.

A Comparative Analysis of the Level of Occupational Health : Before and After the Subsidiary Program on Health Care Management of Small Scale Industries (영세사업장 보건관리 지원사업 실시 전후의 산업보건수준 비교 분석)

  • Jung, Hye Sun
    • Korean Journal of Occupational Health Nursing
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    • v.4
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    • pp.58-83
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    • 1995
  • The small scale industries which have less than 30 employees occupy 86.5% of total number of industries in Korea. And though they have higher accident rate and lower environmental condition than big industries, it has been not mandatory to appointing health care manager at factory. So, from 1993, government subsidizes to the health care management of small industries. The purpose of this study is to identify the real feature of health care status in small industries, and to evaluate the level of health care management, before and after the subsidiary program. 65 small plating industries which have been managed by the same health care management support institution in 1993 were selected for study. Of the 65 industries, 3 which have not taken both environmental evaluation and health screening in 1994, and 9 which have closed were excluded from study sample. And the remaining 53 were analyzed by using the results of environmental evaluation and health screening, reported to the Ministry of Labor, before and after the subsidiary program, the analysis was done by the comparison of the two year paired data of the same industry. Over-permissible-limit rate, health screening implementation rate, above grade C rate were calculated and compared. The status of health care management ; 1. Of the sample industries, 96.9% provide protective equipment and 80.0% set up ventilating system. Protective gloves (89.2%) and protective clothing (80.0%) are widely provided, but ear plugs (4.6%) are rarely provided. 21.5% of the protective equipment are well put on, and 40.4% of the ventilating systems function well. 2. In 1993, 35 industries, 53.8% of the sample, checked working environment twice. Over-permissible-limit rates of heavy metal (12.2%), suspended particle (11.1%), noise (5.5%) were high. To put on protective equipment and to set up local ventilating system were pointed out by the examiners. 3. General health screening was done at 63.1% of the sample industries and 35.3% of total workers were examined. Specific health screening was done at 93.8% of the sample industries and 75.4% of workers were examined. 15.5% of workers was provided to be above grade C and to have digestive system disease (43.3%), circulatory disease (18.9%), and hematopoietic disease (14.2%), etc. 4. In 1993, the subsidiary program of health care management was provided in forms of health education, health counseling, and rounding check of working field. And 61.5%, 83.0%, 55.4% of sample industries respectively received it. The average visit per industry was 1.8. Comparisons of the level of occupational health before and after the subsidiary program ; 1. Over-permissible-limit rates of hazardous factors of 1993 and that of 1994 were compared. The rates of suspended particle, noise, organic solvent of 1994 (37.5%, 13.4%, 24.2% respectively) were higher than that of 1993 (25.0%, 6.0%, 6.3% respectively). In the case of acid, there was no difference between the rate of 1993 and that of 1994. Only the rate of heavy metal decreased from 12.9% in 1993 to 3.0% in 1994. 2. General health screening was done at 38.7% of the sample industries in 1993 and at 44.6% in 1994. But the implementation rate of specific health screening decreased from 72.4% in 1993 to 64.6% in 1994. 3. The implementation rate of specific health screening was analyzed by some health factors. The rate of suspended particle increased from 61.8% in 1993 to 91.2% in 1994. But the rates of the others-noise, organic solvent, heavy metal, specific chemical substances-decreased. 4. Above grade C rate in health screening increased from 27.8% in 1993 to 35.5% in 1994. But that of endocrine disorders and pulmonary disease decreased.

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Adsorption Characteristics of Oxyanions on Ferrihydrite and Mineral Phase Transformation (페리하이드라이트의 산화음이온 흡착 특성과 광물상 변화)

  • Gyure Kim;Yeongkyoo Kim
    • Economic and Environmental Geology
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    • v.56 no.3
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    • pp.301-310
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    • 2023
  • Ferrihydrite is an iron oxide mineral that is easily found in the natural environment, including acid mine drainage, and has a low crystallinity and high specific surface area, resulting in high reactivity with other ions, and can remove environmentally hazardous substances. However, because ferrihydrite is a metastable mineral, there is a possibility of releasing adsorbed ions by phase transformation to other minerals having low surface area and high crystallinity. In this study, the adsorption characteristics of arsenate, chromate, and selenate on ferrihydrite and the oxyanion removal efficiency of ferrihydrite were studied considering mineral phase transformation. At both pH 4 and 8, the adsorption of oxyanions used in the study were in good agreement with both Langmuir and Freundlich adsorption models except for selenate at pH 8. Due to the difference in surface charge according to pH, at pH 4 a higher amount of ions were adsorbed than at pH 8. The adsorption amount were in the order of arsenate, chromate, and selenate. These different adsorption models and adsorption amounts were due to different adsorption mechanisms for each oxyanions on the surface of ferrihydrite. These adsorption characteristics were closely related to changes in the mineral phase. At pH 4, a phase transformation to goethite or hematite was observed, but only a phase transformation to hematite was observed at pH 8. Among the oxyanion species on ferrihydrite, arsenate showed the highest adsorption capacity and hardly caused phase transformation during the experimental period after adsorption. Contrary to this, chromate and selenate showed faster mineral phase transformation than arsenate, and selenate had the lowest retardation effect among the three oxyanions. Ferrihydrite can effectively remove arsenate due to its high adsorption capacity and low phase transformation rate. However, the removal efficiency for other two oxyanions were low by the low adsorption amount and additional mineral phase transformation. For chromate, the efficient removal is expected only at low concentrations in low pH environments.