• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.755-764
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• 2009

To estimate the pollutant removal efficiency by surface sediment, matter content within surface sediment and its release from the sediment were investigated at 12 sites in the Sihwa constructed wetland. The content of COD, TOC, IL, TN, and TP within sediment varied temporally and spacially, showing ranges of 4.1~7.7 mg/g, 0.29~2.81%, 1.88~8.15%, 0.03~0.35%, 362~1,150 ${\mu}g$/g, respectively. The contents of organic matter and TN were significantly highest in March and decreased towards fall (March${\geq}$May${\geq}$July${\geq}$September, p=0.003 for COD, p=0.001 for TOC, p=0.017 for IL, p=0.015 for TN), whereas TP content was not significant statistically in difference between sampling times. The contents of heavy metals also varied largely with sampling sites and times (As:3.5~3.9 ${\mu}g$/g, Cd:0.08~0.38 ${\mu}g$/g, Cr:51.8~107.0 ${\mu}g$/g, Cu:16.4~81.8 ${\mu}g$/g, Pb:26.~81.8 ${\mu}g$/g, Zn:85~559 ${\mu}g$/g). As compared with sediment quality guideline, the content of organic matter within surface sediment of the Sihwa constructed wetland was classified as unpolluted level. In contrast, the contents of TN, TP and heavy metals were classified as medium or severe pollution state, except some heavy metals (Cu and Pb). From the results of release experiment, TN, Pb, and Zn tend to be removed by surface sediment, but TP, Cd, and Cu have a tendency to released from sediment. Therefore, a relevant plan to improve the removal efficiency of pollutant (especially phosphorus) by surface sediment in the Sihwa constructed wetland is needed.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.16-24
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• 2007

An investigation on the polluted sediments in the Lake Sihwa and the benthos that inhabited on the sediments was conducted. Cost effective remediation alternatives were derived form the results of the investigation. The sediment samples taken from four sampling points out of thirteen showed relatively high heavy metal (particularly copper) concentrations which exceeded the Effects Range Low (ERL) of the National Oceanic and Atmospheric Administration, USA. The four sampling points were located in front of industrial complexes. Although the heavy metals appeared to have affected the growth of the benthos, the concentration of it did not exceed the criteria of dredging that were developed by Netherlands or the State of Washington, USA. However, contamination by organic matters and sulfur compounds was severe, which exceeded the criteria of dredging that were established in Japan. The sediments taken from the four sampling points which were contaminated with heavy metals showed higher organic matter content in general. The organic matters in the sediments depleted oxygen in summer, which appeared to be fatal to the benthos. A comprehensive analysis on the sediments, benthos, and other environmental impact from the contaminated sediments drew a conclusion that the benthonic environment of the Lake Sihwa needed a stepwise remediation, giving a particular emphasis on the clean up of the sediments upstram of the Lake which could cause odor problems to the nearby residential area.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.3
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• pp.215-221
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• 1993

중국(中國)은 1991년에 새로운 토양계통분류법(土壤系統分類法)을 1차(次) 시안(試案)으로 확정 발표하였다. 본 체계는 미국의 Soil Taxonomy 체계와 비슷한 형태계량적규준(形態計量的規準)(Morpho-metric definition)으로 되어 있고 전산(電算)프로그램화(化)도 가능한 체계로 되어 있다. 분류체계는 목(目)(Order, 토망(土網)), 아목(亞目)(Suborder, 아망(亞網)), 군(群)(Group, 토류(土類)), 아군(亞群)(Subgroup, 아류(亞類)), 속(屬)(Family, 토속(土屬)), 통(統)(Series, 토종(土種))으로 되어 있고, 현재 13개 목망(目網), 33개 아목(亞目), 77개 군(群), 301개 아군(亞群)으로 분류되어 있다. 특징적표층(特徵的表層)은 유기표층(有機表層) 등(等) 8종, 진단표하층(診斷表下層)(차표층(次表層))은 표백층(漂白層) 등(等) 10종, 기타 특징토층(特徵土層)은 석회적표층(石灰的表層) 등(等) 12종, 그리고 암성(岩性) 등(等) 23종의 토양 생성적(生成的) 특징(特徵) 또는 현상(現像)을 분류기준으로 쓰고 있다. 분류상의 특징은 고위도(高緯度)나 고산지대(高山地帶)의 영구동결층(永久凍結層)을 강조하여 아목수준(亞目水準)에서 분류하였고 논토양이나 관개퇴적토(灌漑堆積土), 영양분(營養分)이 심층(深層)까지 집적(集積)된 채전(菜田) 등(等) 인위적(人爲的) 영향(影響)을 크게 받은 토양을 최고차(最高次) 분류단위(分類單位)인 목수준(目水準)에서 독립(獨立)시키고 있을 뿐 아니라 인위적인 교란(攪亂)을 받았으나 아직 단면(斷面)의 발달이 없는 토양을 초육토(初育土)의 아목수준(亞目水準)에서 구분하고 있다.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.383-390
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• 1992

In the periods of July 31 to August 10. 1988 and March 9 to 13. 1989. sediment samples were collected from the South Sea stations (010] to 092]) located in the area from $N 32^{\circ}$/30' to $34^{\circ}$/30', of latitude and from E $123^{\circ}$ 30' to $128^{\circ}$30' of longitude. These samples were analyzed for the number of total heterotrophic bacteria and extracellular digesting enzyme activities. In the 1989 spring period the number of heterotrophic bacteria in the sediment surface layer was increased more than 100 times at the maximum compared to that in the 1988 summer period. The proportion of fresh water bacteria to total heterotrophic bacteria was also higher in the spring period than the summer period. The extracellular digesting enzyme activities were higher in spring season than summer. Although the water content of sediment in the spring period was lower than that the summer period. the ash weight indicating organic material content was higher. These results means that the diameters of sediment particles were larger in spring than summer but the input of organic material into the sediment was greater. Based on these results bacterial distributions in the sediment layer of South Sea depend greatly on the season due to the effect of fresh water. During the spring season plankton could grow extensively owing to the inorganic nutrients input by the vertical mixing in the water column, then be precipitated into the sediment. Organic nutrients supplied from enzymatic degradation of polymeric particle from plankton can increase the bacterial number, too.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.89-101
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• 2003

River deposits and farmland soils were analyzed to investigate the pollution level of heavy metals in the vicinity of the Goro abandoned Zn-mine. Surface (0-40 cm) and subsurface (40-100 cm) soils were collected around a main river located at the lower part of the Goro mine, and analyzed by ICP-MS for Cd, Cu, Pb, Zn and Cr after 0. 1N HCI extraction and by AAS for As after IN HCI extraction. Concentrations of cadmium and lead at the surface river deposits close to the mine were over the Soil Pollution Warning Limit (SPWL), and 43% of sample sites (6 of 14 samples) were over SPWL for As suggesting that river deposits were broadly contaminated by arsenic. Results from farmland soil analysis showed that surface soils were contaminated by heavy metals, while only arsenic was over SPWL at 50% of sampling sites. Main pollution mechanism around the Goro mine was the discharge of mine tailing and waste rocks from the storage site to the river and to adjacent farmland during flood season. Pollution Grades for sample locations were prescribed by the Law of Soil Environmental Preservation, suggesting that the pollution level of heavy metals around the Goro mine was serious, and the remediation operation fur arsenic and the isolation of mine tailing and waste rocks from river and farmland should be activated to protect further contamination. The area needed to clean up was estimated from pollution distribution data and the remediation methods such as a soil washing method and a soil improvement method were considered as the further remediation operation for arsenic contaminated soils and river deposits around the Goro abandoned mine.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.191-200
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• 2014

Gas hydrates play a significant role in the global carbon cycle and climate change because methane, a greenhouse gas, can be released from the dissociation of gas hydrate. Anaerobic oxidation of methane (AOM) is an important process that consumes more than 90% of the methane released into the hydrosphere and atmosphere. In this study, the microbial community associated with the methane gas hydrate sediment in the Ulleung basin, East Sea of Korea (UBGH) was analyzed by phylogenetic analysis of the mcrA and 16S rRNA gene libraries. A vertical stratification of the dominating anaerobic methane oxidizer (ANME)-1 group was observed at the surface and the sulfate methane transition zone (SMTZ). The ANME-2c group was found to be dominant in the high methane layer. The archaea of marine benthic group B, which is commonly observed in the AOM region, accounted for more than 50% of the identifications in all sediments. Nitrate reducing bacteria were predominant at SMTZ (Halomonas: 56.5%) and high methane layer (Achromobacter: 52.6%), while sulfate reducing bacteria were not found in UBGH sediments. These results suggest that the AOM process may be carried out by a syntrophic consortium of ANME and nitrate reducing bacteria in the gas hydrates of the Ulleung Basin of the East Sea.

• Korean Journal of Microbiology
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• v.38 no.2
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• pp.119-126
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• 2002

ATP concentrations far estimating total microbial biomass in the sediment were measured in three different marine sedimentary environments. ATP concentrations were highest in the surface sediment and decreased with increasing sediment depth and distance from the land. The results indicated that the benthic microbial biomass is primarily controlled by nutrient inputs from the overlying water column. Because of the longer residence time and adsorption to the sediment, the variations in organic carbon (OC) contents with sites and depths were not as distinct as that of ATP, and the correlation between OC and ATP was not significant in the coastal sediments. No significant correlation between OC and ATP in the coastal sediments also suggested that microbial biomass in the labile organic-enriched coastal sediment is suppressed by the grazing of higher trophic level such as meiofauna. Overall regional and vertical distribution of ATP indicated that h\`w can be a relevant tool for measuring total microbial biomass in various marine sedimentary environments.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.183-187
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• 1998

In order to characterize the microbial distribution at sediments of Lake Daechung, soil samples were collected at two depths of 0.5~2 cm and 19~21 cm of Chudong(static) and Hoenam(streaming) site on May 18th(before rainy season) and on August 24th in 1998(after rainy season), and then the density(CFU/g soil) of microorganisms including bacteria, actinomycetes, and fungi was investigated by the viable cell counting method. Microbial density at streaming site was on the whole 3.9-fold higher than that at static site. Bacterial densities examined before and after rainy season was revealed to be similar, whereas actinomycetes and fungi exhibited higher distribution after and before rainy season, respectively. The microbial distribution was not generally reduced with the increase of depth and was rather higher at some deep sites. On comparing with the microbial densities of grass land around the lake, bacteria, actinomycetes, and fungi at lake sediments on the average showed the distribution of 52.9%, 35%, and 7%, respectively. However, their distribution except for fungi which exhibited 71.2% was mostly found to be somewhat higher than at the shore of lake.