• Applied Chemistry for Engineering
• /
• v.10 no.4
• /
• pp.543-547
• /
• 1999

The utilization of fly-ash containing high levels of the unburned carbon was investigated. In this study adsorbents were manufactured from fly-ash ad a raw material and the manufactured adsorbents were applied to the waste-water treatment including heavy metals. Varying the anthracite(Jangsung coal) content, three types of pellet were made. The carbon content of pellet increased appreciably upon the addition of anthracite. After carbonization and activation using the pellets, adsorbents showed following characteristics; the range of hardness was between 85% and 96%, iodine number was from 100 mg/g to 300 mg/g. In proportion to the anthracite addition, hardness and iodine number increased. Through the adsorption experiments of heavy metals, removal efficiencies of Pb and Cr by manufactured adsorbents were over 90%. In case of fly-ash, removal efficiencies of Pb and Cr were 31.5% and 5.6% respectively. The reason why removal capacities of manufactured adsorbents were higher than fly-ash was postulated that adsorption capability was improved by unburned carbon and $SiO_2$ which included in fly-ash during steam activation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.41 no.3
• /
• pp.190-198
• /
• 2008

There is an increasing concern over heavy metal contamination of paddy soils and the subsequent translocation of heavy metals to rice. Objective is to monitor the status and long-term trend of heavy metal contamination in paddy soils, periodically. In 2007 survey, the average concentrations of As(arsenic), Cd(cadmium), Cu(copper), Ni(nickel), Pb(lead), and Zn(zinc) in 2,010 paddy soils nationwide were 0.87, 0.08, 3.33, 1.19, 4.95 and $4.67mg\;kg^{-1}$, respectively. Few sites, which were contaminated by As in 2003 and 2007 survey and by Ni in 1999 and 2007 survey, were over the threshold level for soil contamination designated by the Soil Environmental Conservation Act in Korea. Long-term change was shown that As, Ni, and Zn were gradually increased whereas Cd and Cu were decreased. In the distribution of extractable heavy metal contents, the modes of each heavy metal content were similar with the average contents of each heavy metals. Mean value of heavy metals except copper in paddy soils was higher than median value. It means that the downward distribution of heavy metal content in paddy rice was shown against normal distribution.

• Korean Journal of Food Science and Technology
• /
• v.36 no.4
• /
• pp.523-526
• /
• 2004

There are few studies on toxic metals in fruits. Therefore, we examined contents of toxic metals in fruits (n=386) available in Korean markets. The samples were digested with acids, then analyzed by inductively coupled plasma spectrometer (ICP) or atomic absorption spectrophotometer (AAS) for lead (Pb), cadmium (Cd), and arsenic (As). The contents of mercury (Hg) were also determined using a mercury analyzer, Contents of toxic metals in fruits were as follows [minimum-maximum (mean), mg/kg]; Hg 0.0001-0.019 (0.001), Pb 0.001-0.410 (0.013), Cd 0.001-0.035 (0.000), and As 0.001-0.210 (0.017). Our results showed that metal contents in fruits in Korean markets were similar to those reported in other countries. Average weekly intakes of Hg, Pb, and Cd from fruits are about 1-2% of Provisional Tolerable Weekly Intakes (PTWI) set by FAO/WHO Joint Food Additive and Contaminants Committee for safety evaluation.

• The Korean Journal of Ecology
• /
• v.27 no.3
• /
• pp.141-146
• /
• 2004

This paper reports on Pb and Cd concentrations in the tissues of 76 individuals of 16 rare bird species found dead across Korea. In most of species, Pb concentration was higher in kidney and bone than in liver. The range of the mean liver Pb was 0.47 (Cygnus cygnus)∼3.74 ㎍/wet g (Asio flammeus). Based on hepatic Pb concentrations, 39 (51.3%) of the 76 individuals were classifed as background level (〈2㎍/wet g), 35 (46.1%) were elevated level (〉2㎍/wet g) and 2 (2.6%) were poisoned level (〉10㎍/wet g). These results were indicated many rare birds were suffered from chronic Pb exposure. Cd concentration was generally higher in kidney than in liver and bone. The range of the mean kidney Cd was 0.06 (Bubo bubo)∼l.75㎍/wet g (falco subbuteo). Only one of the 76 individuals had elevated Cd concentration (〉2.7㎍/wet g) in kidney. These results indicated most of rare birds had low Cd accumulations.

• Korean Journal of Environmental Agriculture
• /
• v.31 no.3
• /
• pp.264-270
• /
• 2012

BACKGROUND: The purpose of this study was that serum metabolic and hematological variables were measured to investigate the detoxication effect of Taraxacum mongolicum extract on male albino rat exposed with lead and mercury. METHODS AND RESULTS: For this study, Pb and Hg-exposed( 50 ppm) albino rats was used, and the treatments were carried out in three doses of 100 mg/kg, 200 mg/kg and 500 mg/kg as dry weight of T. mongolicum extract. T. mongolicum extract could improved the body weight gain and feed efficiency ratio, except to food intake. The levels of biochemical factors elevated by Pb-Hg mix exposure, which are Bilirubin, Alkaline phosphatase(ALP), glutamic oxaloacetate transaminase(GOT), glutamic pyruvate transaminase (GPT), lactate dehydrogenase(LDH), ceatinine and blood urea nitrogen(BUN), were significantly reduced in all treated groups as compared to Pb-Hg mix exposure alone. T. mongolicum extract was shown to suppress the accumulation of Hg and Pb in serum by dose dependent manner. CONCLUSION: Therefore, this study suggest that T. mongolicum extract might have the potential effect to minimize the toxic effects of Pb and Hg.

• Journal of the Korean Ceramic Society
• /
• v.32 no.11
• /
• pp.1269-1275
• /
• 1995

Effects of GeO2 addition on the thermal and structural stabilities of PbO-Bi2O3-Ga2O3 glasses were studied. Thermal stabilities, as assessed by the weighted thermal stability factors [(Tx-Tg)/Tg], increased with GeO2 concentraton from 0.097 to 0.210 with the addition of 20 mol% GeO2. Increasing GeO2 content resulted in the decrease of apparent density, molar volume, refractive index and thermal expansion. On the other hand, IR transmission cut-off (λT=50%) moved from 6.73${\mu}{\textrm}{m}$ for the ternary PbO-Bi2O3-Ga2O3 glass to shorter wavelength side, 5.98${\mu}{\textrm}{m}$ for a glass containing 20mol% GeO2. There were little change with GeO2 content, however, in the activation energies for the viscous flow of approximately 140 kcal/mole within the temperature interval of 300~50$0^{\circ}C$. Addition of GeO2 to PbO-Bi2O3-Ga2O3 glasses enhanced the thermal and structural stabilities significantly at the expense of their infrared transmittance. An appropriate compsomise between these two opposite trends should be made following the specifications of the final applications.

• Applied Biological Chemistry
• /
• v.45 no.2
• /
• pp.92-96
• /
• 2002

Present contamination levels of soils along the major roadsides of Seoul, Korea were investigated, and base-line data were accumulated for future use. Topsoil $(1{\sim}5$ cm) and subsoil $(20{\sim}50$ cm) from five districts (Gangdong-, Gwangjin-, Nowon-, Seodaemun- and Seongdong-gu) were sampled. The collected samples were airdried, passed through 2-mm sieves, and analyzed to determine the physicochemical properties including pH, EC, CEC, exchangeable cations (Ca, Mg, K, and Na), and heavy metal contents (Cd, Cu, Pb, and Zn). Soil textures of topsoils and subsoils were mainly loamy sand and sandy loam, respectively. The range of pH was $4.5{\sim}10$.0 with an average of 7.5 for both topsoil and subsoil, which is much higher than that of the forest soils in Seoul. The ranges of 0.1 N HCI extractable Cd, Cu, Pb, and Zn contents for both topsoils and subsoils were $0.0l{\sim}l.19$, N.D. (not $detected){\sim}228$.99, $N.D.{\sim}352$.54, and $2.97{\sim}332$.96 mg $kg^{-1}$, respectively. Most of the average heavy metal contents were lower than the concern level of the Soil Environment Conservation Act of Korea, but were much higher than those of the , forest soils in Seoul. Some sites were higher in heavy metal contents than the concern levels; in particular, the average Cu content in Seongdong-gu was much higher than the concern level, 50 mg $kg^{-1}$. Careful management of the soil to prevent the aggravation of the present contamination level and the dissemination of contamination is highly recommended.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.21 no.4
• /
• pp.125-133
• /
• 2016

We investigated the distribution of organic matter and trace metals in surface sediment from Tonyeong coast. To determine the status of trace metal pollution, we also conducted an ecological risk assessment. Relatively high concentration of TN (total nitrogen), TOC (total organic carbon), and AVS (acid volatile sulfide) was found in surface sediment located in the narrow channel (site 35-38). Spatial distribution of Cd, Cr, Ni, Co, Hg, and Zn in surface sediment was similar and high Cu concentrations were found in narrow channel. The assessment of heavy metal pollution was derived using the Enrichment factors (EF). The enrichment factor indicated that Cd was no enrichment (EF<1), Pb, Cr, Ni, Co, Zn, and Hg were minor enrichment (1

• Journal of Soil and Groundwater Environment
• /
• v.16 no.1
• /
• pp.19-31
• /
• 2011

This study had been carried out to investigate spatial and temporal variations of the concentrations of trace metals for contaminated surface water in creek affected by leachate from the tailings impoundment of the Yeonhwa II mine for about 2 years. It was also to ascertain the metal removal efficiency for potentially deleterious metals by the artificial and natural attenuation processes such as retention ponds and hydrologic mixing of uncontaminated tributaries. The concentrations of As, Pb, Cd, and Cu for leachate in the rainy season were not detected. On the other hand, the concentrations of Zn, Fe, Mn, Al, and $SO_4^{2-}$ in the rainy season for leachate were 2-66 times higher than those in the dry season, due to the oxidation of the sulfide minerals and the dissolution of the secondary minerals. The concentrations of Zn and Cd for leachate and surface water of the upper creek in the rainy season exceeded the criteria of River Water Quality and Drinking Water Quality but in the dry season, those of analyzed all the metals (As, Pb, Cd, Cu, Zn, Cd, Fe, Mn, and Al) for surface water sampled at the study area were below the criteria of River Water Quality and Drinking Water Quality. In regard of the attenuation efficiency for the concentrations of metals, Fe, Mn, Al, Zn, Cd, As, and Cu were removed highly at retention ponds, while the removal efficiency for major cations and sulfate ($SO_4^{2-}$) were related to mixing of the uncontaminated tributaries. Therefore, the major attenuation processes of the metal and sulfate contents in creek affected by leachate from a tailing dump were precipitation (accompanied by metal co-precipitation and sorption), water dilution, and neutralization.

• Korean Journal of Environmental Agriculture
• /
• v.2 no.1
• /
• pp.13-17
• /
• 1983

The influence of planting time and age of reclaimed fields on the contents of heavy metals in vegetable crops in suburban areas was investigated. Investigated crops were 4 radish cultivars, Chinese cabbage, spinach, Garland chrisanthemum, and Welsh onion. Cd, Pb, Cu, and Zn were analyzed. The results obtained were as follows. 1) For radishes except Altari-mu and Welsh onion, the highest concentrations of heavy metals were recorded in roots whereas, for Chinese cabbage and Garland chrisanthemum, the highest concentration was appeared in leaves. 2) For lettuce, radishes, and spinach, the lowest concentrations of heavy metals were recorded in winter and the concentrations were the same between spring and autumn. 3) In lettuce difference of concentrations of heavy metals were not appeared between field age after reclamation with sewege sludge. 4) The concentrations of heavy metals observed was not harmful to human health.