• Nuclear Engineering and Technology
• /
• v.55 no.8
• /
• pp.2889-2896
• /
• 2023

The waste acceptance criteria for heavy metals in mixed waste should be developed by reflecting the leaching behaviors that could highly depend on the repository design and environment surrounding the waste. The current standards widely used to evaluate the leaching characteristics of heavy metals would not be appropriate for the silo-type repository since they are developed for landfills, which are more common than a silo-type repository. This research aimed to explore the leaching behaviors of cementitious waste with Pb, Cd, and Sb metallic and oxide powders in an environment simulating a silo-type radioactive waste repository. The Toxicity Characteristic Leaching Procedure (TCLP) and the ANS 16.1 standard were employed with standard and two modified solutions: concrete-saturated deionized and underground water. The compositions and elemental distribution of leachates and specimens were analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES) and energy-dispersive X-ray spectroscopy combined with scanning electron microscopy (SEM-EDS). Lead and antimony demonstrated high leaching levels in the modified leaching solutions, while cadmium exhibited minimal leaching behavior and remained mainly within the cement matrix. The results emphasize the significance of understanding heavy metals' leaching behavior in the repository's geochemical environment, which could accelerate or mitigate the reaction.

• Korean Journal of Pharmacognosy
• /
• v.44 no.2
• /
• pp.200-208
• /
• 2013

The aim of this study was to evaluate the shelf-life of Bojungikgi-tang (Buzhongyiqi-tang in Chinese) by long-term storage test. Experiments were performed to evaluate the stability such as the selected physicochemical, pH, identification, heavy metal, microbiological experiment, and amount of marker compounds under a long-term storage test of Bojungikgi-tang decoction. The significant change was not showed in pH, heavy metal, microbiological, and identification test based on long-term storage test. Furthermore, the HPLC analysis was performed for the determinations of liquiritin, glycyrrhizin, nodakenin, and hesperidin in Bojungikgi-tang by long-term storage test. We were calculated shelf-life of Bojungikgi-tang decoction based on the amount change of four constituents. Consequently, Shelf-life by four compounds at room temperature was predicted 23 month. The suggested shelf-life would be helpful on the storage and distribution of herbal medicine.

• Journal of Soil and Groundwater Environment
• /
• v.6 no.4
• /
• pp.13-23
• /
• 2001

In this study, the characteristics of pH variations and contaminant distribution in soil are investigated during electrokinetic treatment for the purpose of restoring contaminated soil with heavy metal. For these objects, laboratory test for the kaolin contaminated by lead was performed. During electrokinetic treatment, lead was transported from anode to cathode. And 75% of lead removed within 80% region of the specimen. Most lead, however, that transported from anode to cathode precipitated in the vicinity of cathode compartment, thus the amount of lead removed by electroosmosis was little. Electrokinetic treatment satisfied regulation criteria of Korean Soil Environment Conservation Law within almost region of the specimen. But enhancement methods can be regarded as inevitable requisite for the cathode region.

• 레미콘
• /
• no.10 s.69
• /
• pp.2-11
• /
• 2001

This paper describes the feasiblity of recycling sewage dredged soils as fine affrefate. This paper describes the feasibility of recycling sewage dredged soils as fine aggregate. The specific gravity of the dredged soils was smaller than that of sand due to the effect of dredged sludge. However, the grain size distribution of the dredged soils is relative well graded, and the results of the heavy metal concentration from the leaching test of the dredged soils was significantly lower than the requirements of the allowable criteria. Therefore, the effect of recycling of dredged soils on environment the as fine aggregate was negligible. Also, the specific gravity of the dredged and washed soils was similar to that of sand, and the dredged and washed soils for the most part showed lower heavy metal leaching characteristics than those of dredged soils, Also, the results of the study for evaluation the recycling feasibility of dredged and washed soils as fine affrefate. The organic impurity content of the dredged and washed soils was lower than the requirements of the Korean industrial Standards, and the mortar compressive strength using the washdredged soils also met those of the Korean industrial Standards. And, the strengths of the dredged and washed soils were over 95% of those of the NaOH-treated samples. Therefore, it is expected that the dredged soils will be able to be an alternative for fine aggregate.

• Journal of the korean society of oceanography
• /
• v.32 no.3
• /
• pp.120-127
• /
• 1997

Depositional environment off the Shihwa Dam has been studied to investigate the change of sedimentation process and the pollution. In order to understand how the sediments are distributed, polluted and modified, depositional factors have been analyzed and compared with the previous data. Study area, located off the Shihwa Dam, was surveyed to collect 25 bottom samples and 2 cores in 1996 and echo-sounding in 1997. These sediments were analyzed for the study of the global characteristics of sediment such as grain size and organic matter. Among these samples, the selected twenty surface sediments were analyzed for the comparison with their contents of metallic elements (Al, Mn, Fe, V, Cr, Co, Ni, Cu, Zn, Cd, Pb, As). According to field and lab analysis of sediments, three sedimentological zones have been generally identified around study area; near the dam (sandy Silt), near the dike (Sand) and offshore (silty Sand) zones. Textural parameters show that the content of silt and clay is dominant near the dam excepting the dike zone of LNG Storage Base and offshore (Palmido). The total concentration of Mn, Ni, Fe, Zn and Cd in bulk sediments was increased after the construction of the dam, while the content of Mn and Cr were higher near tidal channel than in the offshore area. Meanwhile, the annual increasing pattern of some heavy metal has appeared in this area. Based on this primary study, modification of the depositional environment may be caused by the construction of the dam and LNG Storage Base. Additionally, environmental evaluation on organic/inorganic factors has been suggested for interpreting environmental changes caused by coastal development in the nearshore such as the Shihwa coastal area.

• Korean Journal of Pharmacognosy
• /
• v.43 no.3
• /
• pp.257-264
• /
• 2012

The purpose of this study was to estimate the shelf-life of Ssanghwa-tang by long-term storage test. Experiments were conducted to evaluate the stability such as the selected physicochemical, pH, identification, heavy metal, microbiological experiment under a long-term storage test of Ssanghwa-tang. The significant change was not showed in pH, heavy metal, microbiological, identification test and quantitative analysis based on long-term storage test. The contents of albiflorin, paeoniflorin, cinnamic acid, liquiritin, and glycyrrhizin in long-term storage test were 66.8-93.1 ${\mu}g/mL$, 429.0-495.0 ${\mu}g/mL$, 3.8-4.4 ${\mu}g/mL$, 32.0-38.1 ${\mu}g/mL$, and 66.8-71.7 ${\mu}g/mL$, respectively. Shelf-lifes by 5 compounds about 3 lots at room temperature were predicted 21-37, 14-21, and 16-72 months, respectively. The suggested shelf-life would be helpful on the storage and distribution of herbal medicine.

• Journal of Environmental Health Sciences
• /
• v.18 no.1
• /
• pp.6-11
• /
• 1992

This study was carried out to investigate exposure level, size distribution, and respirable mass fraction of airborne coal dust and heavy metal concentration of respirable coal dust at each work site in coal briquet factory from July 1991 to September 1991. Geometric mean of total dust concentration was 10.88mg/m$^{3}$ at storage shop, 8.22mg/m$^{3}$ at pulverize shop, and 3.79mg/m$^{3}$ at rotary press shop, respectively, but those at storage and pulverize shop were higher than TLV. Geometric mean of respirable coal dust concentration wat 1.03mg/m$^{3}$ at storage shop, 0.78mg/m$^{3}$ at pulverize shop, and 0.55mg/m$^{3}$ at rotary press shop, respectively, which were lower than TLV Aerodynamic 50% cutoff diameter of the suspended coal dust was 5$\mu$m at rotary press shop and 6.8$\mu$m at storage shop, ranged to thoracic particulate defined by ACGIH, and deposited in the region of repiratory system. The mass fraction rate of respirable dust to the total coal dust was 26.2% at rotary press shop, 18.8% at storage shop, and 13.8% at pulverize shop, respectively. Heavy metal concentrations of the respirable coal dust were 0.028mg/m$^{3}$ ib Fe, 0.0081mg/m$^{3}$ in Cu, and 0.0039mg/m$^{3}$ in Pb.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.10a
• /
• pp.45-46
• /
• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2006.04a
• /
• pp.547-548
• /
• 2006

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2007.10a
• /
• pp.230-231
• /
• 2007