• Clean Technology
• /
• v.11 no.1
• /
• pp.29-39
• /
• 2005

Polychlorinated biphenyls, (PCBs) are a group of highly toxic chlorinated industrial chemicals used as dielectrics, coolants and lubricants in electrical transformers. This article reviewed the state-of-the-art on technologies for decomposition of Polychlorinated biphenyls (PCBs), one of the persistent organic materials (POPs). The purpose of this study was to evaluate the feasibility of decontaminating PCBs contaminated pollutants using treatment technologies such as chemical dechlorination, photodegradation and biological transformation.

• Environmental Engineering Research
• /
• v.14 no.4
• /
• pp.212-219
• /
• 2009

Emission characteristics of air pollutants from three commercially operating cement kilns co-burning waste were investigated. The major heavy metals emitted were mercury (Hg), zinc (Zn), nickel (Ni), chromium (Cr), lead (Pb), cadmium (Cd), and arsenic (As) Removal efficiency of the bag filter was above 98.5% for heavy metals (except Hg), and above 60% for Hg. Higher fractions of heavy metals entering the bag filter were speciated to cement kiln dust. On average, 3.3% of the -heavy metals of medium and low toxicity (Pb, Ni, and Cr) entering the bag filter were released into the atmosphere. Among highly toxic heavy metals, 0.14% of Cd, 0.01% of As, and 40% of Hg entering the bag filter were released into the atmosphere. In passing through the bag filter, the proportion of oxidized Hg in all cases increased. Emission variations of hazardous air pollutants in cement kilns tested were related to raw materials, fuel, waste feed and operating conditions. Volatile organic compounds detected in gas emissions were toluene, acrylonitrile benzene, styrene, 1,3-butadiene, and methylene chloride. Although hazardous air pollutants in emissions from cement kilns co-burning waste were within the existing emission limit, efforts are required to minimize their levels.

• Journal of the Korean Society of Visualization
• /
• v.5 no.1
• /
• pp.30-36
• /
• 2007

The global environment is deteriorating at an alarming rate, despite of enhanced international environmental regulation. Many studies have been performed to reduce toxic pollutants. Recently, plant-based phytoremediation technology for moving toxic contaminants from soil and water has been receiving large attention. Arsenic-contaminated soil is one of the major pollutant sources for drinking water. Pteris erotica has been known as a hyper-accumulator of arsenic from soils. In this study, we investigated the effect of arsenic absorption on sap flow inside xylem vessels of Pteris. The synchrotron X-ray micro-imaging technique was employed to monitor the refilling process of water containing arsenic inside the xylem vessels of Pteris's leaves and stems non-invasively. The captured phase-contrast X-ray images show both anatomy of internal structure and transport of water inside Pteris. The exposure of Pteris to arsenic solution was found to increase largely the water raise speed in xylem vessels. The present results would provide important information needed for understanding the mechanisms of accumulation and transportation of toxic materials in plants.

• Toxicological Research
• /
• v.16 no.4
• /
• pp.285-291
• /
• 2000

So far, investigation of environmental pollution has been achieved in field study. This remains the most exhaustive approach, current dimensions of environmental researches and their inherent complexity require that relatively inexpensive and simple laboratory procedures are developed to make possible the screening of large numbers of sites and samples. At this point. microbioassay has been high-lighted. The purpose of this study is to evaluate the water pollution using microbioassay. Two microbioassay methods were optimized and validated for the sensitive and quantitative determination of total toxic effects in the water. EROD(Ethoxyresorufin-O-deethylase) microbioassay was focused to detect PARs, PCBs and dioxinlike components in the water and E-screen assay to xenoestrogens. The EROD microbioassay was executed in rat hepatoma cell line, H4IIE and E-screen assay in MCF7-BUS cell line. Kumho river was selected for this study. 5ι of river water was extracted using combined solid-phase extraction in static adsorption mode with soxhlet extraction. Pollutants adsorbed to the XAD-4 resin were recovered by elution with ethyl acetate and methylene chloride (1 : 9). Toxic effects of extracts were determined by EROD-microbioassay and E-screen assay. EROD activities of water samples were 7.24-72.24 ng/ι MEQ. The estrogenic effect of various water samples is quantitatively evaluated by EEQ. The EEQ of samples range from 0.05 to 6.07 ng-EEQ/ι. These results suggested that Kumho river was highly polluted with organic toxic chemicals.

• Journal of Korean Society for Atmospheric Environment
• /
• v.27 no.3
• /
• pp.255-271
• /
• 2011

ACE-Asia (Asian Pacific Regional Aerosol Characterization Experiment) in spring 2001 was a turning point to trigger international research interest on Asian dust (AD). This basically arose from the lack of research on AD, the important natural phenomenon to characterize the Northeast Asia. In contrast, health risk related to AD has been the primary concern in Korea. Although due in part to severe AD events of 2001~2002, research and mitigation measures on AD in Korea are typically based on the assumption that AD events are increasing in frequency and severity. However, contrary to the trend in Korea, the number of AD days and emission amounts of AD in China have decreased since 1980s. This paper reviews the impacts of AD on ambient air quality and variations in toxic substances during the AD event, reflecting the concern in Korea. While a great amount of dust particles flow into Korea during the AD event, a considerable amount of dust particles are locally generated as well. Since dust particles are mixed with toxic substances as they pass over polluted areas, the levels of toxic substances become lower in dust particles that do not pass over polluted areas. Broadening the research scope on AD is warranted to understand the AD as an important natural phenomenon, irrespective of its associated health risk.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.04a
• /
• pp.133-134
• /
• 2002

미량독성 유해물질은 크게 중금속 성분과 잔류성 유기오염물질 (POPs, persistent organic pollutants)로 나눌 수 있다. 아직은 우리 사회의 관심이 직접 주변에서 확인할 수 있는 국내 배출에 머물고 있으나 미량독성 유해물질로 분류되는 많은 물질들이 분해가 어렵고 대기 중 체류시간이 길어 장거리 이동의 가능성이 매우 크다. 실제 오염물질 배출이 거의 없는 북극의 북극곰, 물개, 물고기에서도 미량독성 유해물질 검출이 보고되고 있는데, 다른 지역에서 배출된 독성물질들이 침적과 휘발을 반복하며 이동하는 가운데 기온이 낮은 극지방에 축적됨으로써 나타난 현상이다. (중략)

• Proceedings of the Korea Society of Environmental Biology Conference
• /
• 2002.11a
• /
• pp.123-126
• /
• 2002

Pollutants that are persistent, bioaccurnulative, and toxic have been linked to numerous adverse effects in human and animals, PBTs include heavy metals, polychlorinated biphenyls (PCBs), dioxins, polycyclic aromatic compounds (PACs) in addition to pesticides. This study focuses on toxic effects of the PBTs except pesticides on insects. Eight PBTs were selected from subgroups: three heavy metals (Pb, Hg, and Cd), two PCB mixtures (Aroclor mixtures 1 and 2), 2,3,7,8-tetrachlorodibenzo-p-dioxin, two monophenols (4-octylphenol and 4-nonylphenol), and tetrabutyltin, Beet armyworm, Spodoptera exigua, was used as test target insect species. Three physiological markers (metamorphosis, immune reaction, and follicle patency) were assessed in each exposure to different doses of the PCBs. Heat-shock proteins as molecular markers were also analyzed in response to the PCBs. All tested PBTs were toxic to metamorphosis from larvae to pupae when they were applied with diet. Two PCB mixtures were the most toxic compounds in this assay by giving significant toxicity at 0.005 ppm, while others had from 10 to 1000 ppm. Dioxin (0.1 ppb), tetrabutyltin (0.1 ppb), Pb (10 ppb), and Hg (0,01 ppb) were potent to inhibit immune reactions analyzed by inducing phenoloxidase activity and blocked phospholipase $A_2$ enzyme, Tetrabutyltin and dioxin significantly induced follicle cell patency, but their effects were lower than that of endogenous juvenile hormone, Dioxin, Pb, Hg, and Cd could induce the expression of heat shock proteins that were detected by immunoblotting against human HSP70 monoclonal antibody. HSP78 and HSP80 were upregulated in response to the PBTs. This expression was detected from the fat body and epidermis at as fast as 4h after injection. All these results clearly suggest that PBTs give significant ecotoxicity to insects that are valuable organisms in our environment.

• Journal of Korean Society for Atmospheric Environment
• /
• v.18 no.E1
• /
• pp.21-28
• /
• 2002

Air quality issues in Korea rapidly changed at the beginning of the 1990s from primary to secondary pollutants starting in Seoul, the capital of Korea. The present frame of national air pollution monitoring networks was established between the end of the 1980s and the beginning of the 1990s. Background monitoring was initiated in the middle of the 1990s in response to increasing public concern about the long-range transport of air pollutants. Apart from the national monitoring, both routine and intensive measurements of fine particles have been made for research purposes since the middle of the 1990s at several background sites. However, air pollution monitoring in urban areas for other purposes was relatively scarce as national monitoring has been concentrated in these areas. Although ozone pollution has become a significant issue in major metropolitan areas every summer, only a little information on ozone precursors is available. During the past few years, the number of national monitoring stations has greatly increased. The government has a plan to gradually expand monitoring items as well as stations. It is anticipated that highly detailed information on both photochemical reactants and products will be available within the next several years. More emphasis will be placed on toxic substances based on risk assessment in monitoring for both research and policy making.

• Environmental Analysis Health and Toxicology
• /
• v.19 no.2
• /
• pp.141-151
• /
• 2004

We exposed juvenile puffer fish, Takifugu obscurus(30 days after hatching) to various aqueous pollutants including 4 kinds of inorganic metals (Ag, Cd, Cu and Hg), 2 organotin compound.; (tributyltin ［TBT］ and triphenyltin［TPhT］) and 5 polycyclic aromatic hydrocarbon (PAH) compounds (chrysene, fluoranthene, naphthalene, phenanthrene and pyrene) to estimate median lethal concentrations (LC50s) of each pollutant after the 96-hour acute exposure. Among the inorganic metals, Hg (52 $\mu\textrm{g}$/L; 96-h LC50) was most toxic to test animals and followed by Ag (164 $\mu\textrm{g}$/L), Cu (440 $\mu\textrm{g}$/L) and Cd (1180 $\mu\textrm{g}$/L). Aqueous TBT was more toxic between the two organotins; the 96-h LC50 for TBT (5.1 $\mu\textrm{g}$/L) was 3 times lower than that of TPhT (17.3 $\mu\textrm{g}$/L). The acute toxicity of PAH compounds was highest for chrysene (1.5 $\mu\textrm{g}$/L; 96-h LC50) and decreased in the order of pyrene (65 $\mu\textrm{g}$/L) > fluoranthene (158 $\mu\textrm{g}$/L) > phenanthrene (432 $\mu\textrm{g}$/L) > naphthalene (8690 $\mu\textrm{g}$/L). The toxicity of PAH compounds wat closely related to their physico-chemical characteristics such as $K_{ow}$ and water solubility, and well explained by simple QSAR relationship. The sensitivity of puffer fish to various inorganic and organic pollutants was generally comparable to various fish species widely used as standard test species in previous studies and further evaluation should be conducted to develop adequate testing procedure for T. obscurus when used in various toxicity tests.

• Environmental Analysis Health and Toxicology
• /
• v.11 no.1_2
• /
• pp.31-39
• /
• 1996

Leachate from municipal solid waste (MSW) landfill, effluent from leachate treatment plant, and ground water sample from a monitoring well near landfill site were tested for an acute toxicity. Microtox toxicity test was used for testing the acute toxicity of leachate and other samples. EC$_{50}$ values which a concentration of pollutant for reducing 50% light output from luminescent bacteria, Photobacterium phosphoreum were determined to assess the toxicity of pollutants as well as the relative toxicity. In addition, characteristics of leachate were studied and compared to those of phenol and pentachlorophenol (PCP) which are typical aquatic toxic pollutants. For leachate, EC$_{50}$ for 30 min incubation was 10.8%, while for phenol and PCP, 46 ppm and 1.2 ppm, respectively. the relative toxicity of treated leachate by in situ aeration with activated sludge was reduced to more than 75% of toxicity of the untreated leachate. Microtox toxicity test was failed to figure out EC$_{50}$ values for groundwater from a monitoring well since the relative toxicity of the unconcentrated sample was too low to estimate EC$_{50}$. Addition of activated carbon to leachate was reduced the relative toxicity. The reduction Pattern of the relative toxicity of leachate by mechanical aeration was similar to that of PCP, but different from that of phenol. These findings suggest that the toxicity of leachate may come from PCP-like toxic compounds rather than phenol-like one. In conclusion, the process of aeration with activated sludge might be very important to reduce the environmental toxicity of leachate. And Microtox test could be a reasonable bioassay for screening and monitoring the environmental toxicity of leachate from municipal solid waste landfill as well as for determining the reduction efficiency of the leachate toxicity by various treatment processes in leachate treatment plant.