• Economic and Environmental Geology
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• v.32 no.6
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• pp.633-644
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• 1999

Gully pot is a part of urban darainage system to butter the runoff water fluxes from road to rivers and to minimize environmental pollution by prevending over the surrounding area. A series of studies have been carried out concerning the physicochemical characteristics of the sewage sludge sediments sttling down in such a gully pot in order to over to evaluate the contamination for heavy metals such as pb, Zn, Cu and Cd. The roadside soil and sewage sludge samples from gully pots were characterized by XRD analyses and sequential extraction : Zn 2595.7$\mu$g/g; Cd9.8$\mu$/g; Cu602.5$\mu$g/g; Pb260.0$\mu$g/g),because of a long-term accumulation of vehicle- and industrial-related pollutants. Mean Zn concentration in Yeouido (3873$\mu$g/g) and Junggu(3262$\mu$g/g)areas are 4-5 times higher than those in Dobonggu area, suggesting that Zn may be derived from automobile traffic (including the rubber of automobile tires). The mean concentrations of Cu and Cr are very significantly high in Junggu and Gurogu areas, possibly due to the industrial activities in these areas. The low Pb levels throughtotut the whole study areas in Seoul can be accounted for the use of unleaded gasoline since 1987. Sequential extraction experiments illustrate that a major part of Zn is bound to FII and FIII, representing about 88% of the total Zn concentration. Fraction IV, related to orgnic matter, is mostly significant for Cu accounting for 60% of the total Cu, and FII is next in importance. The main carriers of Pb are the fractions III, II and FIV, and in that order. The behavior of Cd is quite different from other elements (Zn, Cu, Pb), and most of the Cd is associated with FV. Changes in the physicochemical environments (such as acidification) may result in severe environmental pollution of surface water and rivers with respect to heavy metals (especially Zn and Cu).

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.345-351
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• 2015

This study investigated the optimum depth for the application of bioremediation in contaminated coastal sediment using a lab scale column experiment. The biostimulants were placed in the top surface of the sediment facing seawater, 3cm, 6cm and 10cm of the depth from the surface, respectibely. During the experiment, the changes of organic pollutants and heavy metal fractions in the sediment were monitored in 1 month and 3month time intervals. The organic pollutants found during various analysis such as chemical oxygen demand, total solids and volatile solids, significantly reduced when the depth of the biostimulant was 3cm or less. In contrast, at a depth of over 6cm, the reduction of organic pollutants decreased, and the results were similar to the control. Heavy metals fractions in the sediment also changed with the depth of the biostimulants. The exchangeable fraction of the metals was quite reduced at the sediment surface in the column, but the organic bound and residual fractions considerably increased at a depth of 3cm. Based on this study, the optimum biostimulants depth for in-situ bioremediation of contaminant coastal sediment is 3cm from the sediment surface.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.43-57
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• 2005

Twelve bottom sediments and three cores were collected in Juam reservoir for a study on transportation, which was controlled by particle grain size (2mm-200{\mu}m,\;200-100{\mu}m,\;100-50{\mu}m,\;50-20{\mu}m,\;<20{\mu}m), and vertical distribution of heavy metals. Sediment cores were sliced into 2 to 5 cm intervals to measure heavy metal concentrations in interstitial water and sediments with depth. Pb isotopic compositions of core samples were determined to calculate sedimentation rate. Regardless of sampling sites, levels of heavy metals and trace elements in bottom sediments are nearly constant with mean values of $14.9\;{\mu}g/g\;for\;As,\;0.81{\mu}g/g\;for\;Cd,\;30.7{\mu}g/g\;for\;Cu,\;34.7{\mu}g/g\;for\;Ni,\;63.3{\mu}g/g\;for\;Pb\;and\;87.9{\mu}g/g\;for\;Zn$. In general, Cu, Pb, Zn, Wi, and Cr in fraction of $<20{\mu}m$ exhibit the highest concentration, but content of As is the highest in grain size of $2\;mm-200\;{\mu}m$ and $200-100\;{\mu}m$. Fe and Mn occur as the dissolved compositions of the highest concentrations in interstitial waters and increase in their concentrations toward lower part of cores. On the contrary, concentrations of Zn and Cu show the highest value in the uppermost part in cores, suggesting these elements are released from reductive dissolution of hydroxides and oxidation of organic matters under different redox conditions. The highest accumulations of Cu, Ni, Pb, and Zn contents in the sediment cores are observed at 0-4 cm layers, and concentrations of Cu and Pb are especially high, implying these heavy metals are originated from anthropogenic sources. The apparent sedimentation rate estimated using unsupported $^{210}Pb$ is 0.91 cm $year^{-1}$, corresponding about 10 cm sedimentation in total depth since construction of Juam dam. These results will provide available information for management of bottom sediment in Juam reservoir.

• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.603-616
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• 2007

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.684-689
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• 2012

In the present study, an efficient mercury-tolerant bacterial strain (RS-5) was isolated from heavy-metalcontaminated industrial effluent. Under shake flask conditions, 97% of the supplemented mercuric chloride was sequestered by the biomass of RS-5 grown in a tryptone soy broth. The sequestered mercuric ions were transformed inside the bacterial cells, as an XRD analysis of the biomass confirmed the formation of mercurous chloride, which is only feasible following the reaction of the elemental mercury and the residual mercuric chloride present within the cells. Besides the sequestration and intracellular transformation, a significant fraction of the mercury (63%) was also volatilized. The 16S rRNA gene sequence of RS-5 revealed its phylogenetic relationship with the family Bacillaceae, and a 98% homology with Lysinibacillus fusiformis, a Gram-positive bacterium with swollen sporangia. This is the first observation of the sequestration and volatilization of mercuric ions by Lysinibacillus sp.

• Resources Recycling
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• v.7 no.5
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• pp.13-18
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• 1998

This study was carried out to understand the properties of the E.A.F. steel-making dusts for stabilization processing. The properties are related to mincral composition, shape, particle size, magnetism, density, porosity and leaching characteristic. the dust particles, the size of which ranges from sub-micron to tens-micron, were mainly spherical like balls that were agglomerated each other: the large particles were generally Fe-rich and the small particles were spherical like balls that were agglomerated each other: the large particles were franklinite (ZnFe$_{2}O_{4}$), magnetite (Fe$_{3}O_{4}$) and zincite (ZnO) by XRD analysis. When the dusts were sieved by a wet process, the particle fraction over 200 mesh had 1.5 wt.% with magnetite and quartz. The particles in the size range of 200-500 mesh consisted of magnetite, franklinite. The 82 wt.% of the steel-making dusts were occupied by the particles finer than 500 mesh and contained franklinite and zincite as main mineralogical compositions. When the dusts of around 78% porosity compressed under the load of approximately 1 KPa, the porosity decreased to 68% and to 535 under around 13 KPa. When the E.A.F. dusts were leached according to the Korea standard leaching procedure on the waster, the heavy metals exceeding the leaching criteria were cadmium, lead and mercury.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.E2
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• pp.57-68
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• 2002

Atmospheric dry deposition fluxes and size segregated concentrations of particulate metal elements were measured at four sites in Kunpo, a small city in the Seoul metropolitan area in Korea. At each site, aerosol samples were collected by dry deposition plates, a cascade impactor, and a coarse panicle rotary impactor during four sampling periods. At all sites, the average fluxes of metals measured during daytime were higher than nighttime fluxes due to higher wind speeds and higher ambient concentrations during daytime. The average fluxes of crustal elements (Al, Ca) were 1∼2 orders of magnitude higher than anthropogenic elements (As, Cd, Cu, Mn, Ni, Pb, and Zn). The daytime fluxes of Al and Ca were between 90 and 12000 $\mu\textrm{g}$ m$\^$-2/ day$\^$-1/, and the nighttime fluxes of Al and Ca were between 20 and 2200 $\mu\textrm{g}$ m$\^$-2/ day$\^$-1/. The daytime fluxes of Pb, a typical anthropogenic element, were between 20 and 160$\mu\textrm{g}$ m$\^$-2/ day$\^$-1/, and the nighttime fluxes of Pb were between ND and 100$\mu\textrm{g}$ m$\^$-2/ day$\^$-1/. Also the ambient metal concentrations during daytime were higher than nighttime. Based on a dust emission estimation study in Kunpo, it was found that dust emissions during daytime are higher than nighttime. The concentrations of crustal elements were higher than anthropogenic elements. The distributions of heavy metals were mainly in small particles (D$\_$p/ 9㎛). The fraction of crustal elements in the large particles (D$\_$p/> 9㎛) were higher than anthropogenic elements.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.332-339
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• 2015

The objective of this study was to evaluate the effectiveness of different biochars on the removal of heavy metals from aqueous media. The experiment was carried out in aqueous solutions containing $200mg\;CdL^{-1}$ or $200mg\;PbL^{-1}$ using two different biochars derived from soybean stover and orange peel (20 mg Cd or $Pbg^{-1}$ biochar). After shaking for 24 hours, biochars were filtered out, and Cd and Pb in the filtrate were analyzed by flame atomic absorption spectrophotometer (FAAS). In order to provide information regarding metal binding strength on biochars, sequential extraction was performed by modified SM&T (formerly BCR). The results showed that 70~100% of initially added Cd and Pb was adsorbed on biochars and removed from aqueous solution. The removal rate of Pb (95%, 100%) was higher than that of Cd (70%, 91%). In the case of Cd, orange peel derived biochar (91%) showed higher adsorption rate than soybean stover derived biochar (70%). Cd was adsorbed on the biochar mainly in exchangeable and carbonates fraction (1st phase). In contrast, Pb was adsorbed on it mainly in the form of Fe-Mn oxides and residual fraction (2nd and 4th phase). The existence of Cd and Pb as a form of surface-precipitated complex was also observed on the surfaces of biochars detected by field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectrometer (EDAX).

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.450-461
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• 2006

In this study, sorption kinetics of lead (Pb) and cadmium (Cd) onto coastal sediments were investigated at pH 5.5 using laboratory batch adsorbers. Four different models: one-site mass transfer model (OSMTM), pseudo-first-order kinetic model (PFOKM) ,pseudo-second-order kinetic model (PSOKM) and two compartment first-order kinetic model (TCFOKM) were used to analyze the sorption kinetics. As expected from the number of model parameters involved, the three-parameter TCFOKM was better than the two-parameter OSMTM, PFOKM and PSOKM in describing sorption kinetics of Pb and Cd onto sediments. Most sorption of Pb and Cd was rapidly completed within the first three hours, followed by slow sorption in the subsequent period of sorption. All models predicted that the sorbed amount at the apparent sorption ($q_{e,s}$) equilibria increased as the CEC and surface area of the sediments increased, regardless of initial spiking concentration ($C_0$) and heavy metal and the sediment type. The sorption rate constant ($k_s,\;hr^{-1}$) in OSMTM also increased as the CEC and BET surface area increased. The rate constant of pseudo-first-order sorption ($k_{p1,s},\;hr^{-1}$) in PFOKM were not correlated with sediment characteristics. The results of PSOKM analysis showed that the rate constant of pseudo-second-order sorption ($k_{p2,s},\;g\;mmol^{-1}\;hr^{-1}$) and the initial sorption rate ($v_{o,s},\;mg\;g^{-1}\;hr^{-1}$) were not correlated with sediment characteristics. The fast sorption fraction ($f_{1,s}$) in TCFOKM increased as CEC and BET surface increased regardless of initial aqueous phase concentrations. The sorption rate constant of fast fraction ($k_{1,s}=10^{0.1}-10^{1.0}\;hr^{-1}$) was much greater than that of slow sorption fraction ($k_{2,s}=10^{-2}-10^{-4}\;hr^{-1}$) respectively.

• Journal of Environmental Impact Assessment
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• v.29 no.1
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• pp.8-25
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• 2020

Industrialization has increased the production of road-deposited sediments (RDS) and the level of heavy metals in those RDS, which can have a significant impact on the surrounding aquatic environments through non-point pollution. Although the relationship between contamination characteristics and particle size of RDS is important for pollution control, there is very little information on this. In this study, we investigated the characteristics of grain size distribution and heavy metal concentrations in the road-deposited sediments (RDS) collected from 25 stations in Shihwa Industrial Complex. The environmental impact of RDS with particle size is also studied. I_geo, the contamination assessment index of each metal concentration, represents the RDS from Shihwa Industrial Complex are very highly polluted with Cu, Zn, Pb and Sb, and the levels of those metals were 633~3605, 130~1483, 120~1997, 5.5~50 mg/kg, respectively. The concentrations of heavy metals in RDS increased with the decrease in particle size. The particle size fraction below 250 ㎛ was very dominant with mass and contamination loads, 78.6 and 70.4%, respectively. Particles less than 125 ㎛ of RDS were highly contaminated and toxic to benthic organisms in rivers. RDS particles larger than 250 ㎛ and smaller than 250 ㎛ were contaminated by the surrounding industrial facility and vehicle activities, respectively. As a result of this study, the clean-up of fine particles of RDS, smaller than 125-250 ㎛, is very important for the control and reduction of non-point pollution to nearby water in Shihwa Industrial Complex.