• The Journal of the Petrological Society of Korea
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• v.18 no.4
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• pp.279-291
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• 2009

Radon is a natural radionuclide originated from radioactive decay of radium in rocks and soil. It is colorless, odorless and tasteless elements that mainly distributed as gaseous phase in soil pore space. The present study analyzed the characteristics of long-term radon variation in granitic residual soil at Mt. Guemjeong in Guemjeong-gu, Busan and determined the effects of atmospheric temperature, rainfall and soil temperature and moisture. Periodic measurements of radon concentrations in soil gas were conducted by applying two types of in-situ monitoring methods (chamber system and tubing system). Radon concentration in soil gas was highest in summer and lowest in winter. The variations in soil temperature and atmospheric temperature were most effective factors in the long-term radon variations and showed positive co-relations. The air circulation between soil air and atmosphere by the temperature difference between soil and atmosphere was analyzed a major cause of the variation. However, other factors such as atmospheric pressure, rainfall and soil moisture were analyzed relatively less effective.

• Journal of Korean Society of Forest Science
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• v.106 no.2
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• pp.204-212
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• 2017

Soil disturbance caused by timber harvesting is widely recognized as a potential threat to forest utilization. The degree and extent of soil disturbance is believed to vary with respect to harvesting methods and logging machines. This study has conducted to assess the degree of soil disturbance associated with ground-based cut-to-length (GC) and cable yarding with whole tree (CW) harvesting methods. Soil disturbance was classified using a visual assessment of harvest unit. The properties of soils in different disturbance levels were also evaluated to understand the influence of timber harvesting on soil structure with soil core sampling method. The deep disturbance and soil compaction were observed in sites by 48% and 23% through harvesting areas for GC and CW logging methods, respectively. The results showed that logging machine and number of machine passage had significant influences on soil bulk density and porosity. Soil disturbance types such as rutted, slash cover, and compact were influenced by equipment travel trends in a GC method.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.4-11
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• 2007

There have been increasing concerns about decreasing crop productivity due to salt accumulation in greenhouse soils. The objective of the study was to investigate the impact of rice straw and woodchip application to a salt accumulated greenhouse soil on crop productivity and soil quality. The application of rice straw (RS) and woodchip (W) increased tomato yield and decreased blossom-end rot, and increased yield of Chinese cabbage compared with standard recommended fertilization ($204-103-122kg\;ha^{-1}\;N-P_2O_5-K_2O$ for tomato and $222-64-110kg\;ha^{-1}\;N-P_2O_5-K_2O$ for Chinese cabbage), while less soil residual nitrate, phosphatephosphorus, and potassium. In addition to the organic material application, fertilization reduction based on soil testing may also contribute to relatively low level of soil residual nutrients. Application of the organic material reduced soil bulk density presumably because of improved soil aggregation and structure, and increased biomass C and dehydrogenase activity. In comparison to rice straw, woodchip application resulted in higher crop yield, less amount of soil residual nitrate and lower soil EC, and greater biomass and dehydrogenase activity. The results obtained in this study indicateshowed that woodchip amendment along with reduced fertilization based on soil testing can be one of essential management practices for salt accumulated greenhouse soils.

• Journal of Soil and Groundwater Environment
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• v.13 no.4
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• pp.1-7
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• 2008

This study analyzed for hydrodynamic dispersion characteristics of multi-soil layer (Silt and clay, Find sand, Coarse sand), data of a field tracer test on the multi-soil layer and data of laboratory column experiments on the samples on each soil layers. Through the analysis of permeability and flow, MS (Silt and clay) and FS (Fine sand), which were low effective porosity, were higher average linear velocity while CS (Coarse sand), which was high effective porosity, was higher hydraulic conductivity. Hydraulic conductivity function based on average soil particle diameter was assumed Y=$3.49{\times}10^{-8}e^{15320x}$ and coefficient of determination was 0.90. Average linear velocity function based on average soil particle diameter was assumed Y=$1.88{\times}10^{-7}e^{11459x}$ and coefficient of determination was 0.81. Longitudinal dispersivity function based on average soil particle diameter was Y = 0.00256$e^{5971x}$ and coefficient of determination was 0.98. According to the linear regression analysis of average linear velocity and longitudinal dispersivity, assumed function was Y = 21.7527x + 0.0063, and coefficient of determination was 0.9979. The ratio of field scale/laboratory scale was 54.09, it exhibited scale-dependent effect of hydrodynamic dispersion. Field longitudinal dispersivity (1.39m) was 7.47 times as higher than longitudinal dispersivity estimated by the methods of Xu and Eckstein (1995). Hydrodynamic dispersion on CS layer was occurred mainly by diffusion flow in the test aquifer.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.825-830
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• 2007

사면에서 발생되는 강우유출과정에 기여하는 대공극의 영향은 그 중요성에도 불구하고 잘 알려져 있지 않다. 특히 대공극의 공간적분포특상에 대한 현장측정은 이뤄지지 않았다. 본 연구의 실험지역은 경기도 포천시 광릉수목원에 있는 작은 소유역이다. 이 지역의 정밀한 측량을 하여 수치고도모형(DEM)을 얻었다. 이 수치고도모형을 바탕으로 수치지형분석을 통해 흐름선을 파악하여 총 20지점을 선정하였다. 각 지점에서의 대공극을 통한 수직적인 유동들은 장력침투계를 사용하여 지표면아래 깊이 10cm에서 측정하였다. 공간적 토양의 특성분포를 파악하기 위해 각 지점에서의 체적밀도와 점토함량을 조사하였다. 토양수분의 공간적 분포 특성은 TDR(Time Domain Reflectometry)방식인 TRASE를 이용하여 토양수분 값을 얻었다. 이러한 다양한 공간적 특성들은 대공극발달의 공간적 분포특성을 파악하는 중요자료가 된다. 소유역을 크게 기여사면 면적을 기준으로 상부, 중부, 하부로 나누어 대공극의 유효 공극율과 대공극흐름율을 계산하였다. 상부에서의 유효 대공극율의 평균값과 변동계수는 각각 4.3%, 42.1%이고, 대공극흐름율의 평균값과 변동계수는 각각 45.0%, 26.6%이다. 중부에서는 유효 대공극율의 평균값과 변동계수는 6.8%, 37.3%이고, 대공극흐름율의 평균값과 변동계수는 56.2%, 14.4% 이다. 그리고 하부에서의 유효공극율의 평균값과 변동계수는 12.5%, 58.3% 이고 대공극흐름율의 평균값과 변동계수는 64.5%, 24%이다. 이는 유효 대공극율과 대공극흐름율의 비율은 기여사면 면적이 증가할수록 증가하였다. 이는 대공극을 통한 물 이송 능력이 원두부로 갈수록 증가한다는 것을 보여주고 있다.e, taurine, methionine, phenylalanine은 함량(含量)이 적었다. 5. 일건(日乾)중 총유리아미노산의 변화(變化)는 생시료(生試料)의 경우 2,041.2 mg%였으나 1일(日) 건조(乾燥) 후는 1,784.0 mg%로 감소(減少)하다가 그 이후 계속 증가(增加)하여 20일(日) 건조(乾燥) 후는 5,277.0 mg%였다. 6. 일건(日乾)중 leucine, isoleucine, valine은 대체로 증가(增加)하는 경향(傾向)을 나타내었으나 aspartic acid, proline, taurine은 대체로 감소(減少)하는 경향(傾向)을 나타내었다. 436.59mg%로 가장 많았고 군유산(軍有山) 차엽(茶葉)이 146.94mg%로 가장 적었으며 일반차엽(一般茶葉)의 평균치(平均値)는 264.59mg%, 용장(龍欌) 차엽(茶葉)이 223.10mg%, Yabukita 차엽(茶葉)이 256.49mg%였다. 7) 이상(以上)의 결과(結果)를 종합(綜合)할 때 용장(龍欌) 차엽(茶葉)은 일반차엽(一般茶葉)과 형질(形質) 뿐만 아니라, 성분(成分)도 다르므로 품종(品種)이 다른 수종(樹種)으로 추정(推定)되며 와운(臥雲) 차엽(茶葉)은 일반차엽(一般茶葉)과 형질(形質)은 다르나 성분상(成分上)의 비슷한 점으로 보아 동일계통(同一系統)의 변이(變異)된 대엽종(大葉種)으로 추정(推定)된다.5(${\pm}0.77$0.77) % 의 오차로 크게 감소하였다. 결론: 방사선이 통과하는 경로에 불균질조직인 폐가 존재할 경우에도 불균질조직에 대하여 조직의 밀도를 이용하여 보정하는 방법을 사용하여 투과선량으로부터 종양선량을 계산할 수 있음을 알 수 있었다.X>로 평균$43.26{\m

• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.77-86
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• 2002

Surfactant enhanced in-situ soil flushing was performed to remediate the soil and groundwater at an oil contaminated site, where had been used as a military vehicle repair area for 40 years. A section from the contaminated site (4.5 m $\times$ 4.5 m $\times$ 6.0 m) was selected for the research, which was composed of heterogeneous sandy and silt-sandy soils with average $K_d$ of 2.0$\times$$10^{-4}$cm/sec. Two percent of sorbitan monooleate (POE 20) and 0.07% of iso-prophyl alcohol were mixed for the surfactant solution and 3 pore volumes of surfactant solution were injected to remove oil from the contaminated section. Four injection wells and two extraction wells were built in the section to flush surfactant solution. Water samples taken from extraction wells and the storage tank were analyzed on a gas-chromatography (GC) for TPH concentration in the effluent with different time. Five pore volumes of solution were extracted while TPH concentration in soil and groundwater at the section were below the Waste Water Discharge Limit (WWDL). The effluent TPH concentration from wells with only water flushing was below 10 ppm. However, the effluent concentration using surfactant solution flushing increased to 1751 ppm, which was more than 170 times compared with the concentration with only water flushing. Total 18.5 kg of oil (TPH) was removed from the soil and groundwater at the section. The concentration of heavy metals in the effluent solution also increased with the increase of TPH concentration, suggesting that the surfactant enhanced in-situ flushing be available to remove not only oil but heavy metals from contaminated sites. The removal efficiency of surfactant enhanced in-situ flushing was investigated at the real contaminated site in Korea. Results suggest that in-situ soil flushing could be a successful process to remediate contaminated sites distributed in Korea.

• Journal of Korean Society of Forest Science
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• v.88 no.3
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• pp.364-373
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• 1999

This study aims to clarify the effect of forest management practices(thinning and pruning) on soil physical properties and water quality to get the fundamental information on the facility of purifying water quality after forestry practices. Rainfall, throughfall, stemflow, soil and stream water were sampled at the study sites which consist of Abies holophylla and Pinus koraiensis, in Kwangnung Experimental Forest for 6 months from March 1 to August 7, 1998. Average tree height of the management site increased by 1.8m and 0.6m more than that of the non-management site in Abies holophylla and Pinus koraiensis, respectively. Increment of average D.B.H. at the management site showed 4.7cm and 1.4cm more in Abies holophylla and Pinus koraiensis compared with that at non-management sites. Coarse(less than pF2.7) and total porosities of A layer soil at the management site increased more than those at the non-management sites in both stands. Otherwise, soil bulk density resulted in being reversely. Water qualities of throughfall, stemflow and soil water were buffered more by the management practice in both.

• Journal of Wetlands Research
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• v.18 no.2
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• pp.194-200
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• 2016

The impervious surface rate increased by urbanization causes various problems on the environment such as water cycle distortion, heat island effect, and non-point pollutant discharges. The Low Impact Development (LID) techniques are significantly considered as an important tool for stormwater management in urban areas and development projects. The main mechanisms of LID technologies are hydrological and environmental pollution reduction among soils, media, microorganisms, and plants. Especially, the media provides important functions on permeability and retention rate of stormwater runoff in LID facilities. Therefore, this research was performed to assess the pollutant removal efficiency for different types of media such as zeolite, wood chip, bottom ash, and bio-ceramic. All media show high pollutant removal efficiency of more than 60% for particulate materials and heavy metals. Double layered media is more effective in reducing heavy metals by providing diverse sizes of micro-pores and macro-pores compared to the single layered media. The results recommend the use of different sizes of media application is more cost-effective in LID than a single size of media. Furthermore, soluble proportion of total heavy metal in the stormwater is an important component in proper media selection and arrangement.

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.30-39
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• 2017

In this study, the predictive toxicity of barley Hordeum vulgare was estimated using a modified terrestrial biotic ligand model (TBLM) to account for the toxic effects of $CuOH^+$ and $CuCO_3(aq)$ generated at pH 7 or higher, and this was compared to that from the original TBLM. At pH values higher than 7, the difference in $EA_{50}\{Cu^{2+}\}$ (half maximal effective activity of $Cu^{2+}$) between the two models increased with increasing pH. As Mg concentration increased from 8.24 to 148 mg/L in the pH range of 5.5 to 8.5, the difference in $EA_{50}\{Cu^{2+}\}$ increased, and it reached its maximum at pH 8. The difference in $EC_{50}[Cu]_T$ (half maximal effective concentration of Cu) between the two models increased as dissolved organic carbon (DOC) concentration increased when pH was above 7. Thus, for soils with alkaline pH, the toxic effect of $CuOH^+$ and $CuCO_3(aq)$ are greater at higher salt and DOC concentrations. The acceptable Cu concentration in soil porewater can be estimated by the modified TBLM through deterministic method at pH levels higher than 7, while combination of TBLM and species sensitivity distribution through the probabilistic method could be utilized at pH levels lower than 7.

• Journal of Soil and Groundwater Environment
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• v.22 no.1
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• pp.49-58
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• 2017

Biotic ligand model (BLM) and species sensitivity distribution (SSD) were used to determine the site-specific Cu threshold concentration (5% hazardous concentration; HC5) in soil pore water. Model parameters for Cu-BLM were collected for six plants, one collembola, and two earthworms from published literatures. Half maximal effective concentration ($EC_{50}\{Cu^{2+}\}$), expressed as $Cu^{2+}$ activity, was calculated based on activities of major cations and the collected Cu-BLM parameters. The $EC_{50}\{Cu^{2+}\}$ varied from 2 nM to $251{\mu}M$ according to the variation in environmental factors of soil pore water (pH, major cation/anion concentrations) and the type of species. Hazardous activity for 5% (HA5) and HC5 calculated from SSD varied from 0.076 to $0.4{\mu}g/L$ and 0.4 to $83.4{\mu}g/L$, respectively. HA5 and HC5 significantly decreased with the increase in pH in the region with pH less than 7 due to the decrease in competition with $H^+$ and $Cu^{2+}$. In the region with pH more than 7, HC5 increased with the increase in pH due to the formation of complexes of Cu with inorganic ligands. In the presence of dissolved organic carbon (DOC), Cu and DOC form a complex, which decreases $Cu^{2+}$ activity in soil pore water, resulting in up to 292-fold increase in HC5 from 0.48 to $140{\mu}g/L$.