• Journal of Korean Society for Atmospheric Environment
• /
• v.33 no.3
• /
• pp.241-250
• /
• 2017

Recently, there has been growing interest in the emission characteristics and behavior of anthropogenic mercury compounds from emission sources. It is required to establish a standard for reliable mercury measurement method. Therefore, this study has evaluated the applicability of the new measurement method; Continuous Emission Monitoring (US EPA 30A, CEM). In addition, the reliability evaluation was conducted through Ontario Hydro Method (ASTM D6784, OHM) and Sorbent trap method (US EPA Method 30B). As a monitoring result for three months via CEM from cement kiln, the maximum mercury compounds concentration was about $600{\mu}g/Sm^3$. This is because of the various of raw materials and fuel, and the absence of mercury-control device. The mercury compounds concentrations of OHM, Sorbent trap and CEM were 13.64 $(3.33{\sim}32.41){\mu}g/Sm^3$, $13.94(5.97{\sim}23.44){\mu}g/Sm^3$ and $14.68(6.19{\sim}26.75){\mu}g/Sm^3$, respectively. The relative standard deviations (% RSD) of the three methods were 5.1~40.9%. The result of this study suggest that it is possible to apply the CEM in the cement kiln when, QA/QC such as calibration is verified.

• Ocean and Polar Research
• /
• v.37 no.1
• /
• pp.37-47
• /
• 2015

The effects of low salinity (fertilization success and larval survival) on the limpet Cellana grata were studied at early stages of development using the marine bioassay technique. It was shown that, under normal conditions for development from fertilization to the post veliger stage, the salinity must be not less than 20.0~35.0 psu. However, the fertilization rate and larval survival of C. grata was obviously reduced at 5.0 psu and 10.0 psu, respectively. Mass mortality was estimated to occur at <20.0 psu (48-h $EC_{50}=19.54psu$) and the survival rate of normal veliger larvae decreased with experimental time during exposure. No observed effective concentration (NOEC) and lowest observed effect concentration (LOEC) of post veliger were estimated at 30.0 psu and 25.0 psu, respectively, during 48-h exposure. The tolerance limits of the test species to salinity revealed various concentration ranges of salinity, which may reflect the physiology and ecology of the initial development stages of C. grata. These results demonstrate that reduced salinity is detrimental to the reproductive success and larval survival of C. grata, and if salinity is lowered by natural or anthropogenic sources during spawning, this would lead to decreased reproductive success and larval settlement.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.09a
• /
• pp.35-37
• /
• 2001

This study has investigated the chemical characteristics and the contamination of groundwater in relation to land use in Daejeon Metropolitan City. An attempt was made to distinguish anthrophogenic inputs from the influence of natural chemical weathering on the chemical composition of groundwater at Taejon. Groundwater samples collected at 170 locations in the Taejon area show very variable chemical composition of groundwater, e.9. electrical conductance ranges from 65 to 1,290 S/cm. Most groundwater is weakly acidic and the groundwater chemistry is more influenced by land use and urbanization than by aquifer rock type. Most of groundwater from green areas and new town residential districts has low electrical conductance, and is of Ca-HC $O_3$ type, whereas the chemical composition of groundwater from the old downtown and industrial district is shifted towards a Ca-Cl (N $O_3$+S $O_4$) type with high electrical conductance. A number of groundwater samples in the urbanized area are contaminated by high nitrate and chlorine, and exhibit high hardness. The Ep$CO_2$, that is the $CO_2$ content of a water sample relative to pure water, was computed to obtain more insight into the origin of $CO_2$ and bicarbonate in the groundwater. Factor analysis of the chemical data shows that the HC $O_3$ and N $O_3$ concentrations have the highest factor loadings on factor 1 and factor 2, respectively. Factors 1 and 2 represent major contributions from natural processes and human activities, respectively. The results of the factor analysis indicate that the levels of $Ca^{2+}$, $Mg^{2+}$, N $a^{+}$, Cl and SO4$^2$ derive from both pollution sources and natural weathering reactions.ons.

• Korean Journal of Agricultural Science
• /
• v.46 no.4
• /
• pp.857-868
• /
• 2019

A flooded rice field is one of the significant sources of anthropogenic methane (CH₄) with the intensity of the emissions dependent on management practices. Incorporation of rice straw, which is one of the organic amendments, induces the increase of methane emissions during the flooding season. In this study, we measured of methane emission according to applications of rice straw in different soil textures during a cultivation period in 2017 and 2018. The fallow treatments were non application of rice straw (NA), spring plowing after spring spreading of rice straw (SPSA), spring plowing after previous autumn spreading of rice straw (SPAA), and autumn plowing after previous autumn spreading of rice straw (APAA). The SPSA treatment emitted the highest total methane from loam soil in both 2017 (596.7 CH₄ kg ha^-1) and 2018 (795.4 CH₄ kg ha^-1). The same trend was observed in silt clay loam soil; the SPSA treatment still emitted the highest amount of methane in both 2017 (845.9 CH₄ kg ha^-1) and 2018 (1,071.7 CH₄ kg ha^-1). The lowest emission among the rice straw incorporated plots came from the APAA treatment for both soil texture types in all the seasons. The conversion factors of the SPAA were 0.79 and 0.65 from the loam and silt clay loam soils, respectively. Relatedly, the conversion factors of the APAA were 0.71 and 0.43 from the loam and silt clay loam soils, respectively. The above observations mean therefore that incorporation of rice straw early in the fallow reduces methane emissions in the main rice growing season.

• Journal of Environmental Science International
• /
• v.25 no.6
• /
• pp.865-875
• /
• 2016

In this study, mass concentrations and chemical compositions of $PM_{2.5}$, including water-soluble ions and elements were determined at the 1,100 m-highland of Mt. Hallasan in Jeju Island across four seasons from August 2013 to August 2014. The average mass concentration of $PM_{2.5}$ was $12.5{\pm}8.41{\mu}g/m^3$ with 45.8% of the contribution from eight water-soluble ionic species. Three ionic species ($SO{_4}^{2-}$, $NH{_4}^+$, and $NO{_3}^-$) comprised 96.2% of the total concentration of ions contained in $PM_{2.5}$ and were the dominant ions, accounting for 43.5% of the $PM_{2.5}$ mass at Mt. Hallasan. On the basis of the mass concentration level, seasonal variation, enrichment factor, and relationship among elements, we can presume that Mg, K, Ca, Mn, Fe, Co, Sr, Ba, Nd, and Dy originated mainly from crust or soil and that V, Cr, Ni, Cu, Zn, As, Cd, and Pb were significantly enriched in $PM_{2.5}$ owing to the effects of the anthropogenic emissions. These results and the local distribution of emission sources and topographic characteristics near this sampling site suggest that the compositions of $PM_{2.5}$ collected at the 1100 m-highland of Mt. Hallasan were largely influenced by inflow from outside of Jeju Island.

• Journal of Environmental Science International
• /
• v.22 no.9
• /
• pp.1199-1211
• /
• 2013

Mobile sources produce a significant fraction of total anthropogenic emissions in Korea and have harmful effects on air quality. Mobile emissions are intrinsically difficult to estimate due to complicated road networks and variations of traffic volume with location and time. To measure traffic pollutants with high temporal and spatial resolution under real conditions a mobile laboratory was designed. The mobile laboratory provide concentrations of $SO_2$, CO, NO, $NO_2$ and location coordinate value. This approach allowed for pollutant level measurements on many roads within short periods of time. In this study, on-road concentrations of $SO_2$, CO, NO and $NO_2$ were measured using mobile platform measurement along the 25 main roads in Busan to estimate the average air pollution level in short time difference. The measurements were conducted on favorable meteorological days from 2010 to 2012 and the overall concentrations of $SO_2$, CO, NO and $NO_2$ were 0.006, 0.8, 0.182 and 0.055 ppm respectively. The result showed that the concentration of CO, NO and $NO_2$ on road were twice, 18 times and 2.5 times higher than regional air quality monitoring sites mean in same period.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.5
• /
• pp.638-648
• /
• 2013

To understand the geochemical characteristics of intertidal sediment in a semi-enclosed bay, we measured various geochemical parameters, including grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Hg, and As), in intertidal sediment from three bays (Deukryang Bay, Yeoja Bay, and Gamak Bay) in the southern region of Jeollanam Province. The intertidal sediment in Deukryang Bay consisted of various sedimentary types, such as sand, gravelly muddy sand, mud, and silt, whereas the intertidal sediments in Yeoja and Gamak Bays were composed mainly of mud. The concentrations of IL, COD, AVS and trace metals in the intertidal sediments of the three study regions were relatively high near areas affected by input of stream waters and/or shellfish farming waste. The concentrations of organic matter and trace metals in Gamak Bay were much higher than those in Deukryang and Yeoja Bays, which appears to be due to the influence of anthropogenic pollutants, originating from the city and the industrial complex near Gamak Bay. The evaluation results of organic matter and metal pollution using the sediment quality guidelines showed that the intertidal sediments in the three study regions were not polluted in terms of organic matter and trace metals. In future, sustainable management for sources of organic matter and trace metal is necessary to conserve a healthy benthic ecosystem in intertidal sediments.

• Journal of Environmental Impact Assessment
• /
• v.16 no.5
• /
• pp.327-340
• /
• 2007

The $PM_{10}$ and $PM_{2.5}$ aerosols were collected at Busan from March to May, 2005, and the concentrations of some metallic elements were analysed to study their characteristics. The mean concentration of $PM_{10}$ was $66.5{\pm}23.0{\mu}g/m^3$ with a range of 22.2 to $118.1{\mu}g/m^3$. The mean concentration of $PM_{2.5}$ was $46.1{\pm}17.2{\mu}g/m^3$ with a range of 9.7 to $83.3{\mu}g/m^3$. The ratio of $PM_{2.5}/PM_{10}$ was 0.69 at Busan. The distribution of metallic elements for $PM_{10}$ and $PM_{2.5}$ were Cd${\ldots}$ ${\ldots}$ $PM_{10}$ were $94.9{\mu}g/m^3$ and $63.7{\mu}g/m^3$, respectively. And The mean mass concentrations of Asian dust and non Asian dust in $PM_{2.5}$ were $56.9{\mu}g/m^3$ and $45.1{\mu}g/m^3$, respectively. The mean values of crustal enrichment factors for five elements (Cd, Cu, Pb, V and Zn) were all higher than 10, possibly suggesting the influence of anthropogenic sources. The soil contribution ratios for $PM_{10}$ and $PM_{2.5}$ were 20.5% and 19.4, respectively.

• Journal of Korean Society on Water Environment
• /
• v.22 no.6
• /
• pp.1123-1129
• /
• 2006

Pyrene of natural and anthropogenic sources is one of the toxic, mutagenic polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants. The objectives of this research are to break down pyrene by using ozonation, identify the intermediates and byproducts of pyrene, and test the biodegradability of intermediates and byproducts of pyrene in the aqueous phase. Since pyrene is non-polar, hexane was chosen as a solvent to effectively dissolve pyrene. Pyrene solutions were treated with ozone, as it has high oxidation capacity and electrophilic characteristic. After different ozonation pretreatment times (2, 3, and 10 minutes), intermediates of pyrene in the form of yellowish solid were collected from the hexane solution using a centrifuge. They were identified by gas chromatography/mass spectrometer (GC/MS). $BOD_5$, COD, and E-coli toxicity tests have been performed to assess the ozonation products.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.4
• /
• pp.289-303
• /
• 2009

The chemical and meteorological effects on the concentration variations of ozone ($O_3$) were evaluated based on the intensive air quality measurement (5 pollutants and aromatic volatile organic compounds (AVOCs)) in and out-side an urban valley during spring and summer of 2006. The 5 pollutants measured in the study area include $O_3$, $NO_2$, NO, $PM_{10}$, and CO; the AVOCs include benzene (BEN), toluene (TOL), ethylbenzene (EB), m,p-xylene (MPX), and o-xylene (OX). For the purpose of this study, study areas were classified into two categories: valley area (VA) with a semi-closed topography covering a number of industrial complex, public building, and mountains and non-valley area (NVA) surrounding the suburban and residential areas. In general, the mean concentration levels of most pollutants (except for $PM_{10}$) in the VA were higher than those in the NVA. It was found that the average $O_3$ increase in the VA during spring might result from the combined effects such as the photochemical production from diverse anthropogenic sources and the $O_3$ accumulation due to geographical features (e.g., the semi-closed topography) and wind conditions (e.g., a low wind speed). In addition, the nocturnal $O_3$ increase in the VA during spring was primarily caused by local wind conditions (e.g., mountain and valley winds) with the low wind speed (approximately $1{\sim}2\;m\;s^{-1}$). On the other hand, the $O_3$ difference between the two areas during summer might be because of the photo-chemical production with the $O_3$ precursors (especially the AVOCs) rather than the contribution of wind conditions.