• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.843-853
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• 2009

The sediment samples were collected from Seonakdong River and were analyzed for sulfide species such Acid Volatile Sulfide(AVS) and Elemental Sulfur(ES) and Chromium Reducible Sulfide(CRS). Then characteristics of the formation of sulfide species were investigated for six selected samples. Finally the relationship between environmental factors and sulfate reducing rate(SRR) was investigated using two selected samples. Concentrations of AVS and CRS were relatively high, which suggests that organics input to the sediments has been continued until recently and that potential of heavy metals leaching from the sediments is low. SRR in the sediments was closely related to fraction of fine particles(silt+clay) and also to dissolved organic carbon content of the sediment(DOCsed). The dependences of environmental factors such as organic content, temperature, sulfate concentration on the SRR was relatively strong in the selected experiments conducted with the samples from Noksan gate and Daejeo gate samples. The environmental factor dependencies were stronger in the Noksan gate samples than in the Daejeo gate samples, which is probably due to higher surface area of the Noksan gate sediments.

• Journal of Environmental Science International
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• v.24 no.3
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• pp.275-280
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• 2015

In order to measure the Radionuclides and Concentration, the directly grinded land samples (river soil, pine leaves and mugwort) among the environment samples around the nuclear power plant were filled in a 450 mL Marinelli beaker and weighed to obtain the dry mass ratio of the samples. Then the background and land samples were measured for 80,000 sec. The analysis of the collected land samples showed that most of them contained less radiation nuclide than the detection minimum limit in the 'Ministry of Education, Science and Technology Public Notice No. 2010-32.'In others, the natural radionuclides $^{40}K$ were detected. Of the products of nuclear reaction discharged by a nuclear reaction, $^{134}Cs$ and $^{137}Cs$ are more easily detected, and their discharge sources can be traced using the relative ratio. Although the radioactive concentration in the vicinity of Kori Nuclear Power Plant, which is more than 1,100km away from Fukushima, the Japanese nuclear accident site, continuous monitoring is needed as the radionuclides can still be accumulated in the soil or animals and plants.

• Advances in concrete construction
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• v.11 no.5
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• pp.367-374
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• 2021

The present study investigated the effect of the combined carbonation and steam curing on the physicochemical properties and CO₂ uptake of the Portland cement concrete. Four different curing regimes were adopted during the initial 10 h of curing to evaluate the potential of carbonation curing as an alternative to conventional steam curing in the precast concrete industry from environmental and practical viewpoints. Four combinations of carbonation and steam curing conditions were applied as curing regimes to the samples at an early age. The test results indicated that the samples treated with the combined carbonation and steam curing exhibited higher early strength development compared to the other samples, signifying that carbonation curing can reduce the production time of precast concrete. Furthermore, the CO₂ uptake capacity of the samples was calculated and found to be as high as 18% with respect to the mass of the paste samples. Hence, the simultaneous utilization of steam and CO₂ for the fabrication of precast concrete members has the potential to make precast concrete greener and more cost-effective.

• Mass Spectrometry Letters
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• v.5 no.1
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• pp.12-15
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• 2014

Thermal ionization mass spectrometry (TIMS) was used to determine the concentration and isotope ratio of uranium contained in samples of soil and groundwater collected from Korea. Quantification of uranium in ground water samples was performed by isotope dilution mass spectrometry. A series of chemical treatment processes, including chemical separation using extraction chromatography, was applied to the soil samples to extract the uranium. No treatments other than filtration were applied to the groundwater samples. Isotopic analyses by TIMS showed that the isotope ratios of uranium in both the soil and water samples were indistinguishable from those of naturally abundant uranium. The concentration of uranium in the groundwater samples was within the U.S. acceptable standards for drinking water. These results demonstrate the utility of TIMS for monitoring uranium in environmental samples with high analytical reliability.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.867-876
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• 2012

The concentration of veterinary antibiotics in aqueous and sediment matrices was measured in agricultural irrigation ditches bordering several animal-feeding operations (AFOs) and then compared to its concentration in the watershed. Analytical determination in aqueous samples was based on solid phase extraction (SPE) and appropriate buffer solutions were used to extract residuals in sediment samples. Separation and detection of extracted veterinary antibiotics were performed with high performance liquid chromatograph tandem mass spectrometry (HPLC/MS/MS). In general, higher concentrations of antibiotic were observed in the aqueous phase of irrigation ditches, with the highest concentration of erythromycin hydrochloride (ETM-$H_2O$) of $0.53{\mu}g\;L^{-1}$, than in aqueous watershed samples. In contrast, higher concentrations were measured in river sediment than in irrigation ditch sediment with the highest concentration of oxytetracycline of $110.9{\mu}g\;kg^{-1}$. There was a high calculated correlation ( > 0.95) between precipitation and measured concentration in aqueous samples from the irrigation ditches for five of the ten targeted veterinary antibiotics, indicating that surface runoff could be an important transport mechanism of veterinary antibiotics from field to environment. Further, environmental loading calculation based on measured concentrations in aqueous samples and flow information clearly showed that irrigation ditches were 18 times greater than river. This result suggests the likelihood that veterinary antibiotics can be transported via irrigation ditches to the watershed. The transport via surface runoff and likely environmental loading via irrigation ditches examined in this study helps identify the pathway of veterinary antibiotics residuals in the environment.

• Journal of odor and indoor environment
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• v.17 no.4
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• pp.330-336
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• 2018

The objective of this study was to determine whether crops and fruits absorb the naturally occurring asbestos (NOA). The concentration of asbestos in various crops and fruits grown in NOA areas was analyzed and background levels of asbestos in ambient air and soil samples were assessed. Actinolite/Tremolite asbestos were detected in all soil samples. Among 21 ambient air samples, 2 samples were recorded to contain 0.0005 f/cc (fiber per cubic centimeter) but no asbestos was detected in the other samples using transmission electron microscopy (TEM). However, no evidence suggesting that the crops and fruits could be contaminated by NOA was found in this study. The excess lifetime cancer risks (ELCRs) of ABS scenarios (agricultural activities) used in this study were calculated by using the Arithmetic (AM) and Geometric mean (GM) of ELCRs. The AM and GM of ELCRs estimated from digging soil and weeding activities did not exceed $1{\times}10^{-4}$, which was defined as the general acceptable risk range for exposure. The results of this study would be informative to NOA managers and related policy makers to make plans to prevent unexpected exposure to asbestos to residents living in an NOA area.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.357-368
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• 2017

To establish new metal groundwater standard, 5 metals such as aluminum, chromium, iron, manganese, and selenium were evaluated by Chemical Ranking Of groundWater pollutaNts (CROWN) including possibility of exposure, toxicity, interest factor, connection standard for other media, and data reliability. 430 groundwater samples in 2013 and 2014 were collected semiannually from 110 groundwater wells and they were analyzed for selenium, manganese, iron, chromium, and aluminum. For this study, 430 groundwater samples were categorized into 3 geological distribution features, such as igneous, metamorphic, and sedimentary rock region and geological background levels were divided by pre-selection methods. For the results, the average concentrations of aluminum, chromium, iron, manganese, and selenium in 430 groundwater samples were $0.0008mg\;L^{-1}$, $0.0001mg\;L^{-1}$, $0.174mg\;L^{-1}$, $0.083mg\;L^{-1}$, and $0.0004mg\;L^{-1}$, respectively. In addition, among various geologies, average concentration of selenium was the highest in igneous rock region, average concentrations of chromium, manganese and aluminum were the greatest in sedimentary rock region, and average concentration of iron was the most high in metamorphic rock region. As a result of the geological background concentration with pre-selection method, background concentrations of selenium and aluminum in groundwater samples were the highest from sedimentary rock as $0.0010mg\;L^{-1}$ and $0.0029mg\;L^{-1}$ and background concentrations of manganese and iron in groundwater samples were the greatest from metamorphic rock as $0.460mg\;L^{-1}$ and $1.574mg\;L^{-1}$, and no chromium background concentration in groundwater samples was found from all geology.

• Environmental Analysis Health and Toxicology
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• v.24 no.4
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• pp.293-301
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• 2009

This study was conducted to investigate the distribution of the concentrations of selected trace metals and inorganic anions in five types of drinking water samples (mineral spring water, well water, small community water, municipal tap water, and commercial mineral water) collected from Chuncheon, Gangwon-do in 2007. Forty four samples were analyzed for five metals and five anions using an atomic absorption spectrometer and an ion chromatograph, respectively. Arsenic (As) and nitrate (${NO_3}^-$) concentrations in some groundwater samples did not meet the future (10 ${\mu}g/L$) and current (44 mg/L) Korean drinking water standards, respectively. On the other hand, any municipal tap water samples, the sources of which were lake surface water, satisfied the Korean standards. Human health risk assessment results showed that arsenic in all types of water, especially groundwater including commercial mineral water, may pose both noncarcinogenic and carcinogenic effects on the residents. It is concluded that groundwater is not safe drinking water any longer and that a national survey and follow-up measures need to be taken.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.727-729
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• 2002

In this paper, we proposed quad variable rates ADPCM coding method and its implementation on C6000 DSP, which is modified from the standard ADPCM of ITU G.726 for speech quality improvement considering the environmental noise Four coding rates, 16Kbps, 24Kbps, 32Kbps and 40Kbps are used for speech window samples and the rate decision threshold is decided by the environmental noise level. The object of the proposed method is to reduce the coding rate while retaining the speech quality and the speech quality is considerably close to 40Kbps single rate coder with the coding rate close to 16Kbps single rate coder under the environmental noise. The environmental noise level affects the coding rate and the noise level is calculated per every speech window samples. At high noise level, more samples are coded at higher rates to enhance the quality, but at low noise level, only the big speech signals are coded at higher rates and more speech samples are coded at lower coding rates to reduce the coding rates. The influence of the noise on tile speech signal is considerably high for small signals and the small signal has the higher ZCR (zero crossing rate). The method is simulated in PC and to be implemented on C6000 floating point DSP board in real time operations.

• Environmental Engineering Research
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• v.24 no.3
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• pp.427-433
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• 2019

Sakarya is famous for cucurbit productions in Turkey and cucurbits can grow as big as 560 kg of weight per fruit in its agricultural areas. There is no or limited information about contaminant levels and profiles of the agricultural fields in Sakarya. The purpose of this study is to investigate the levels of polycyclic aromatic hydrocarbons (PAHs) (naphthalene, phenanthrene, pyrene, and fluoranthene) and heavy metal (As, Cd, Cu, Cr, Ni, Pb, Zn) concentrations of the selected fields. Total 33 soil samples were collected from 12 counties of Sakarya where both cucurbits have been produced and organochlorine pesticides have been applied to the fields for more than 30 y during the historical plantation periods. Heavy metal and PAH contents in the soil samples were measured by an Inductively Coupled Plasma Emission Spectroscopy and a Gas Chromatography-Mass Spectrometry. The highest phenanthrene, pyrene, and fluoranthene concentrations were measured as 63.50 ng/g, 134.34 ng/g, 140.0 ng/g, respectively in the soil samples from Geyve County. Cu, Ni, and Cr concentrations were measured as 108.2 mg/kg, 219.9 mg/kg, and 173.1 mg/kg, respectively in Geyve's samples which were also the highest and 2-7 times more than the limit values given in the Turkish Soil Pollution Control Regulation. Precautions need to be taken for Sakarya's agricultural fields which are an important milestone of Turkey's cucurbit and fruit productions since the contaminants can be accumulated in the fruits and edible parts of the plants.