• Journal of Korean Society for Atmospheric Environment
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• v.17 no.6
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• pp.475-485
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• 2001

The presence of airborne particles in the earth atmosphere expert important controls on the global climate because of their effects on the radiative balance. However, there are major uncertainties associated with the direct and indirect radiative effects of aerosols. In addition, their physicochemical properties cannot only the decline of air quality but also damage human health. Airborne particles were collected by two different commercial air samples, high volume sampler(for TSP) and low volume sampler(for P $M_{10}$ ) at the campus of Kunsan National University during February to September, 2000. In most cases, TSP and P $M_{10}$ were sampled once a week for the duration of 24 hours from 9:00 a.m. In addition samples were collected more intenisve, when the yellow dust was expected. Each sample was analyzed for pH and major ions concentration (C $l^{[-10]}$ , S $O_4$$^{2-}$, N $O_3$$^{[-10]}$ , N $a^{+}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$) by ion chromatography and atomic absorption spectrophotometry. Acidity (pH) of TSP and P $M_{10}$ ranged from 5.09 to 8.51 and from 6.22 to 7.54, respectively. The concentrations of airborne particles were found to satisfy both the short and long-term air quality standards during the sampling period. If the ratio of ionic concentrations originating from None sea salt(Nss) to sea salt(ss) in aerosol samples was concerned, it was found that the ionic concentrations from marine environment contributed dominantly in total mass concentration in the airborne particles. When seasonal trends were examined, the TSP concentrations in spring were higher than those of other seasons. It may result form frequent occurrences of yellow dust and during the spring season. The concentration ratio of P $M_{10}$ to TSP ranged from 0.78 to 1 during the sampling period. pH in the airborne particle was highest during spring, but the other seasons maintained almost same level. These results suggest that alkaline species in yellow dust can directly neutralize aerosol acidity. During spring season, yellow dust could be a positive factor that can defer the acidification of surface soil and water by neutralizing acidic aerosols in the atmosphere.osphere.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.1
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• pp.27-36
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• 1996

The Nanji landfill is one of the biggest uncontrolled landfill in terms of its size and scale in the world. Because the landfill was constructed on the very vulnerable alluvial deposit installing no pollution control systems such as bottom liner and leachate collection systems, it has caused a serious adverse effect to near-by groundwater and surface water systems. A through remedial investigation comprising plume detection and site-characterization was performed to design the remedial measure. As a part the investigation, comprehensive water quality study was conducted, using ten existing observation wells and one bundle type monitoring well, to determine the contaminant indicators for the plume delineation and to define the vertical and horizontal variation of specific contaminants via distances from the landfill. The results clearly shows that EC and temperature are a good pollution indicators and the vertical concentrations of specific contaminants measured in the fully screened wells are 20 to 90% more than those measured at the same depth in bundle type well which is located just 2 m apart. This paper presents a cost effective monitoring and sampling method to define the contaminant plume and obtain a basic data for leachate control measures.

• Korean journal of applied entomology
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• v.26 no.2 s.71
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• pp.99-106
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• 1987

Three post-harvest fields each in four rice growing areas, Iri, Naju, Jinju and Taegu were randomly selected and surveyed during December 1986 to examine sclerotial density of Rhizoctonia solani overwintering in the field. Surface soil of $0.09m^2$ area was sampled in each field with three replications and sieved to collect sclerotia. Germiability and pathogenicity of collected sclerotia were examined in the laboratory. Number of sclerotia $({\times}10^6)/ha$ in Iri, Naju, Jinju, and Taegu was estimated from the sample as 2.7, 1.2, 0.7 and 0.6, respectively. Based on sample variance with simple random sampling in each area, number of sampling required for estimating average sclerotial density with the precision of 10% apart from a chance of 1 in 20 was calculated to 41, 132, 232, and 395 for Iri, Naju, Jinju and Taegu, respectively. Percentage of germination of sampled sclerotia on potato sucrose agar (PSA) ranged from 42 to 78% depending on the area, and averaged 60%. About 49% of the germinated sclerotia were pathogenic to a rice cultivar Jinheung that was used to test pathogenicity of the sclerotia. Proportion of viable sclerotia that have both germiability and pathogenicity was thus estimated to 0.29 of total sclerotia collected. R. solani cultures obtained from the sclerotia could be distinguished into three groups based on colony morphology on PSA. Size and number of sclerotia formed on PSA differed between group but were not associated with pathogenicity to Jinheung.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.35-53
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• 2007

Geochemical and isotope studies on the groundwater system of the Youngcheon area were carried out. Most groundwaters belong to Ca-$HCO_3$ and Ca-$SO_4$ types and some groundwaters belong to Na-$HCO_3$ type. Geochemical characteristics of these groundwaters were mainly affected by their basement rocks around the boreholes. High $SO_4$ content of groundwater is the result of reaction with sulfate or sulfide minerals in the host rock. Ca was originated from the carbonate minerals in the sedimentary rock. After the groundwater was saturated with calcite, the Na-$HCO_3$ type groundwaters were evolved by the reaction with plagioclase for a relatively long residence time. This explanation was supported by low tritium contents of Na-$HCO_3$ type groundwaters. ${\delt}a^{18}O$ and ${\delta}D$ data indicate that the groundwaters are of meteoric water origin and there was no difference between the various types of waters. Grondwaters from the boreholes BH-1, BH-9 and BH-12 showed the geochemical and isotopic characteristics of deep groundwater. Most borehole groundwaters except them did not show the systematic geochemical variations with sampling depth indicating that the shallow and deep groundwaters were mixed with each other throughout the study area. The results of water quality analysis indicate that the study area is highly contaminated by the introduction of agricultural sewage.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.86-93
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• 2007

In recent tests using tracer have been frequently conducted by fluorescent tracers. In this study, granular activated charcoal (GAC) as a detector for the fluorescent tracers (rhodamine WT and uranine) was investigated through laboratory and field tests. In the laboratory tests, tracer concentrations of rhodamine WT and uranine determined by the GAC were slightly different from those of standard solutions but they were excellent in linearity. Results show that GAC is excellent as tracer detector when concentration of the fluorescent tracers is greater than 10 & micro; g/L whileas no obvious differences in mixed solutions of the two tracers due to interferences. Compared to conventional methods of water sampling, field results shows a high potential of GAC as a tracer in the field. Our results also show that wet analysis is better for the lower concentrations of tracers whileas dry analysis is good for high concentrations of tracers. This study demonstrates that fluorescent tracer detection using the GAC is very useful and economical for a hydraulic connection between target areas and very longer period of the tracer test.

• Korean Journal of Remote Sensing
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• v.28 no.5
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• pp.489-499
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• 2012

In this paper, a classifier ensemble framework for remote sensing data classification is presented that combines classification results generated from both different training sets and different classifiers. A core part of the presented framework is to increase a diversity between classification results by using both different training sets and classifiers to improve classification accuracy. First, different training sets that have different sampling densities are generated and used as inputs for supervised classification using different classifiers that show different discrimination capabilities. Then several preliminary classification results are combined via a majority voting scheme to generate a final classification result. A case study of land-cover classification using multi-temporal ENVISAT ASAR data sets is carried out to illustrate the potential of the presented classification framework. In the case study, nine classification results were combined that were generated by using three different training sets and three different classifiers including maximum likelihood classifier, multi-layer perceptron classifier, and support vector machine. The case study results showed that complementary information on the discrimination of land-cover classes of interest would be extracted within the proposed framework and the best classification accuracy was obtained. When comparing different combinations, to combine any classification results where the diversity of the classifiers is not great didn't show an improvement of classification accuracy. Thus, it is recommended to ensure the greater diversity between classifiers in the design of multiple classifier systems.

• Journal of Environmental Health Sciences
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• v.46 no.4
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• pp.398-409
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• 2020

Objectives: This study aimed to evaluate environmental exposure to tobacco-specific nitrosamines (TSNAs) by conducting an analysis of the concentration of TSNAs in deposited dust collected from a fertilizer plant and the surrounding village, a simulation of high-temperature drying of tobacco waste, and CALPUFF modeling. Methods: The raw materials of the products, deposited dust (inside and outside the plant and residential area), soil, and wastewater were sampled and the TSNA concentrations were analyzed by LC-MS/MS. As the plant was closed down before the investigation, simulation tests were conducted to confirm the substances discharged during high-temperature (300℃) drying of tobacco waste. CALPUFF modeling was performed to identify the area of influence due to exposure to TSNAs. Results: TSNAs were detected in organic fertilizers estimated to contain tobacco waste, deposited dust, and soil collected from inside and outside the plant. N'-nitrosonornicotine (NNN), 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK), and N'-nitrosoanatabine (NAT) components were detected in five of 15 deposited dust samples collected from the residential area around the plant, while TSNAs were not detected in the five sampling points in the control area. Also, the simulation test for the high temperature drying of tobacco waste found emissions of TSNAs. The CALPUFF modeling results showed that the survey area was likely to be included in the area of influence of TSNA emissions from the plant. Conclusions: It is estimated that harmful tobacco ingredients such as TSNAs were dispersed in nearby areas due to the illegal use of tobacco waste as a raw material to produce organic fertilizers at the plant. These findings assume that the residents have been exposed to TSNAs and suggest that the need for the establishment of measures to manage environmental health.

• Journal of Environmental Health Sciences
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• v.36 no.2
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• pp.108-117
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• 2010

In this study, ambient particulate matter ($PM_{2.5}$ and $PM_{10}$) levels were measured and their chemical and physical properties were characterized. Two sites in Gwangju were sampled once a month from December 2008 to November 2009. The annual mean concentrations of $PM_{2.5}$ and $PM_{10}$ were $26.9\;{\mu}g/m^3$ and $46.3\;{\mu}g/m^3$, respectively, in Nongseongdong and $26.1\;{\mu}g/m^3$ and $44.8\;{\mu}g/m^3$, respectively, in Duam-dong. $PM_{2.5}$ levels were 1.8 times higher than the USA Environmental Protection Agency (EPA) national ambient air quality standard for $PM_{2.5}$ ($15\;{\mu}g/m^3$). The average $PM_{2.5}/PM_{10}$ ratio of 0.58 suggested that $PM_{2.5}$ is a significant component of the ambient particle pollution. The order of concentration of metallic elements in $PM_{2.5}$ and $PM_{10}$ was Si > Al > Fe > Zn > Pb > Cu > Mn. Cd was not detected. The earth crustal enrichment factors for Cr, Cu, Pb and Zn in $PM_{2.5}$ were higher than those in $PM_{10}$. When the earth crustal enrichment factors for Cr, Cu, Pb and Zn were higher than 10, this suggested influence from anthropogenic sources. The soil contribution ratios for $PM_{2.5}$ and $PM_{10}$ were 11.3% and 16.4%, respectively, and were higher in the fall and winter. Anions (${SO_4}^{-2}$, ${NO_3}^-$, and $Cl^-$) comprise 28.7% of $PM_{2.5}$ and 21.4% of $PM_{10}$. The correlation coefficient of Zn-Fe, Mn-Cu, Fe-Cu and Fe-Mn in $PM_{2.5}$ was high in the sampling sites, and metallic elements were primarily from anthropogenic sources such as fuel combustion and vehicle emissions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.100-101
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• 2004

Many researches in Korea have been performed to understand the pollution of stream waters by acid mine drainage. However, few studies have been conducted regarding the effect of particulate and colloidal fractions on the transport of trace metals. To estimate harmful effects of trace metals, it is important to evaluate the particulate and colloidal metals as well as dissolved metals, because particulate and colloidal fractions of trace metals play an important role in transport of trace metals and may adversely affect habitats and organisms in riverine system. Colloids are solids with effective diameters in size range from 0.001 $\mu$m to 1 $\mu$m. According to Jone et al. (1974), metals in surface water, like Al, Fe, and Mn, require filtration with pore-size membranes smaller than 0.45 $\mu$m to define dissolved concentrations. The main objective of this study is to understand the effects of particulate, colloidal, and truly dissolved fractions on the transport and fate of trace metals in acid mine drainage. This study was conducted for the Onjeong creek in the Uljin mine area. Sampling was carried out in 13 sites, spatially covering the area from mine dumps to the downstream Onjeong reservoir. To examine the metal partitioning between particulate, colloidal, and truly dissolved fraction, we used successive filtration techniques consisting of conventional method (using 0.45 $\mu$m membranes) and tangential-flow ultrafiltration (using 0.001 $\mu$mm membranes). Ultrafiltration may seperate much smaller particles from aqueous phase (Josephson, 1984; Hernandez and Stallard, 1988). The analysis of metals were performed by inductively coupled plasma - atomic emission spectrometer (ICP-AES: model Perkin Elmer OPTIMA3000XL). Anions such as SO$_4$, Cl and NO$_3$ were measured with ion chromatograph (IC: model Dionex 120). Sample analysis is still in progress. The preliminary data show that the studied creek is severely polluted by Al, Fe, Mn, Pb and Zn. Toward upstream sites with relatively lower pH, less than 50% of Al and Fe occur in the sorbed form on particles or colloids, whereas more than 80% of Al and Fe occur in the sorbed form in downstream sites or tributaries with relatively higher pH. Less than 30% of Zn is present in particle or colloidal forms in the whole range of creek. Truly dissolved fraction of trace metals is negatively correlated with pH. The Kd values for Al, Fe and Zn consistently increase with increasing pH and decrease with increasing particle concentration.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.755-763
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• 2010

Fine sediment loadings from agricultural watersheds have led to habitat degradation in Lake Takkobu, northern Japan. Fifteen lake sediment core samples were obtained and analyzed to develop a chronology using physical sediment characters, $^{137}Cs$, and tephra. The reconstructed sedimentation rates over the past ca 300 years suggested that sedimentation rates increased drastically after land use development. With a natural sedimentation rate of 0.1-1.1 mm $year^{-1}$ until 1898, lake sedimentation accelerated to 0.6-12.8 mm $year^{-1}$ after 1898. The sedimentation rates after land use change, such as forestry, river engineering works, and agricultural development, were about 6-12 times higher than that under natural conditions, leading to accelerated lake shallowing over the last ca 100 years. Sedimentation rates between 1898 and 1963 differed with location in the lake because of spatial variation in the sediment flux from the contributing rivers and their watersheds. The sedimentation rate in the southern zone between 1898 and 1963 was significantly higher than that in the middle and northern zones, reflecting active sediment production associated with forestry for charcoal production and canal construction for transportation in the southern watersheds and wetlands. The sedimentation rate after 1963 did not vary among the three zones, because decreasing sedimentation was found in most of the southern sites whereas an increasing trend was observed in the middle and northern sites. This result can be explained by shallowing of lake-bottom morphology with sedimentation and the resultant reduction of sediment retention capacity in the southern zone. Moreover, the sedimentation rate at sampling sites close to river mouths increased by 5-32 times compared with natural rates before 1898. The Kushiro River, into which Lake Takkobu drains under regular flow conditions, further contributed to an increased sedimentation rate, because water from the Kushiro River flows back into Lake Takkobu during floods.