• 한국농공학회논문집
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• 제48권3호
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• pp.3-8
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• 2006

The fractions of nitrogen were investigated in the soils of reclaimed and natural tidelands of southwest coastal area of Korea. The content of total-N varied to ranged form 619 to 5,534 mg/kg dry weight with a mean value of 1,857 mg/kg. The order of different fractions of nitrogen was as follows: Acid non-extractable-N > uncounted-N > acid extractable-N > ammonia-N > nitrate-N. The content of ammonia-N, acid extractable-N, and acid non-extractable-N showed highly negative correlations with pH. The content of acid extractable-N and ammonia-N showed highly positive correlation with clay content.

• 한국토양비료학회지
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• 제44권6호
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• pp.1314-1319
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• 2011

This study was carried out to investigate the surface soil organic carbon fractions affecting by different land use types, including needle-leaf forest (FN), broad-leaf forest (FB), pasture, annual upland cropping land (upland), and paddy rice land (paddy). We chose seven regions across Korean inland, considering sea level altitude, and measured soil organic carbon content and physico-chemical properties such as bulk density at a depth of 0~15 cm using core samples in April for the each land use type. In addition, labile organic carbon fractions in soil including light fraction and hot water extractable carbon were investigated. From this study, organic carbon storage (Mg C per ha) in the upper 15-cm soils was highest in FB (37.8), and decreased in the order of pasture (29.1), FN (28.8), paddy (21.9), and upland crop (19.9). In forest, more than 20% of soil organic carbon existed as light fraction, the free organic matter. Hot-water extractable carbon contents of soils in five land use types were lower than 7% of their soil organic carbon content.

• Applied Biological Chemistry
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• 제45권3호
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• pp.152-156
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• 2002

토양중 비소함량이 식물체내 이동에 미치는 영향을 조사하기 위하여 아연 폐광산 근처 논토양과 벼에 함유된 비소함량을 조사하였다. 논토양 중 비소는 total As의 약 52.9%, extractable As의 74%정도가 iron oxide phase에 bound된 비소(Fe-As)였으며 수용성 비소(Ws-As)는 대부분 검출한계 이하였다. 비소의 연속추출 결과, extractable As fraction중 Fe-As가 1 N-HCI 가용성 As와 가장 높은 상관을 나타내었고, 이것은 토양중 Fe-As 의 함량이 많기 때문으로 생각된다. 식물체 부위별 비소의 농도는 뿌리>잎 줄기>곡실순이었으며 곡실 중에 함유된 비소농도는 FDA 식품기준 1.08mg/kg 이하였다. 토양중 As fraction과 식물체 부위별 As함량간의 상관관계를 분석한 결과 Al-As fraction이 뿌리와 0.821, 줄기 0.888, 잎 0.777로 비교적 높은 상관계수를 나타내었고, 작물에 가장 잘 이용될 수 있는 비소의 형태는 Al-As fraction인 것으로 판단된다.

• 생약학회지
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• 제10권3호
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• pp.119-124
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• 1979

Both wild peony and cultivated peony demonstrated a slight effect and tranquilizer of anti-convulsion on the strychinine and picrotoxine but the wild plant was more effective. The methanol extract of cultivated peony root demonstrated a weak effect of muscle loosening but its mixture with water extractable fraction did not have this effect in contrast to the case wild type whose methanol extract mixture with water extractable fraction still retained a strong anti-convulsional muscle loosening effect. Therefore, it is concluded that wild peony root has more analgesic and muscle loosening effect than the cultivated counterpart has.

• 한국토양비료학회지
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• 제41권3호
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• pp.184-189
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• 2008

To assess the relationship between Cd fraction in paddy soils and Cd in polished rice, soils and rice were analyzed at the 3 Cd contaminated paddy fields near closed mines. Major Cd fractions of A field were organically bound (62.6%) and Fe-Mn oxide bound (25.3%) forms. In case of B field, major Cd fractions of B1 field were carbonate bound (46.3%) and Fe-Mn oxide bound (31.6%) form whereas B2 field were residual (54.3%) and carbonate bound (21.8%) form, respectively. It showed a huge difference of Cd fraction each other. 0.1M HCl extractable Cd in soil was positively correlated with Cd in rice. Specially, the ratios of 0.1M HCl extractable Cd against total Cd content in soils were 13.7%, 2.6%, and 0.45% in A, B1, and B2 fields, respectively. These ratio were largely affected with Cd uptake to rice grain. Also, exchangable, Fe-Mn oxide bound, and carbonate bound form, which are partially bioavailable Cd fraction to the plant, were positively correlated with Cd in rice while organically bound and residual form was not correlated. Multiple regression equation was developed with Rice Cd = -0.02861 + 0.07456 FR 1(exchangeable) + 0.00252 FR 2(carbonate bound) + 0.001075 FR 3(Fe Mn oxide bound) - 0.00095 FR 4(organically bound) - 0.00348 FR 5(residual) ($R^2=0.7893^{***}$) considering Cd fraction in soils.

• 약학회지
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• 제33권1호
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• pp.46-53
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• 1989

The extractable organic matter was extraced from airborne particulates collected in Seoul during 1986. It was fractionated to several fracrtions and mutagenicities of them were tested in Salmonella thyphimurium TA98 by Ames method. The neutral fraction showed the highest indirect acting mutagenicity while the highest direct acting mutagenicity was observed in the acidic fraction. Indirect acting mutagenicity of airborne particulate was attributed to its neutral fraction about 88% in average, to acidic about 10% in average and to basic fraction about 2% in average. Direct acting mutagenicity of airborne particulate was attributed to its neutral fraction about 70%, to acidic fraction about 29% and to basic fraction about 1%. Among five subfractions of neutral fraction, the proportion of mutagenicity of polynuclear aromatic hydrocarbon subfraction was 13.2% in indirect acting mutagenicity and 5.0% in direct acting mutagenicity.

• 한국환경농학회지
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• 제5권2호
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• pp.85-94
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• 1986

수도체(水稻體)와 토양(土壤)에서 carbofuran의 거취(去就)를 구명(究明)하기 위하여 C-14 표식(標識) carbofuran을 수도유묘(水稻幼苗)에 담수처리(湛水處理)하고 방사능(放射能)의 분포(分布), 수도체내(水稻體內)에서의 대사(代謝), 토양(土壤)에서의 화학적 전환(化學的 轉換)을 경시적(經時的)으로 조사(調査)하였다. 토양(土壤)에 처리(處理)한 C-14 표식(標識) carbofuran은 쉽게 경근흡수(經根吸收)되어 줄기로 이동(移動), 잎의 첨단부위(尖端部位)에 축적(蓄積)되었으며, 수도체(水稻體)의 근부(根部)에 비해 더 많은 양(量)의 방사능(放射能)이 줄기에 분배(分配)되었다. 수도(水稻) 줄기와 뿌리에서 aqueous phase extracts와 non-extractable fraction의 방사능(放射能)이 경제적(經時的)으로 증가(增加)하는 것은 phase I 및 phase II 반응(反應)이 진행(進行)하는 것으로 해석(解釋)하였다. 수도체(水稻體)와 토양(土壤)의 organic phase extracts에는 현재(現在)까지 알려진 carbofuran과 이의 5종(種) 대사물(代謝物)이 모두 관찰(觀察)되었으며 3-hydroxycarbofuran이 주요(主要) 대사물(代謝物)로 확인(確認)되었다. aqueous phase extracts는 HCl 또는 cellulase 가수분해(加水分解)로 상기(上記)한 6종(種) 화합물(化合物)이 양적차이(量的 差異)는 있었으나, 모두 aglycone으로 확인(確認)되었으며 7-benzofuranol과 3-hydroxycarbofuran이 많이 분리(分離)되었다. 일반토양(一般土壤)에서는 살균토양(殺菌土壤)에 비해 non-extractable fraction의 방사능(放射能)이 크게 증가(增加)하였고, organic phase extrac 방사능(t放射能)은 감소(減少)하였다.

• Environmental Analysis Health and Toxicology
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• 제16권4호
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• pp.143-151
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• 2001

Six rivers were selected as preliminary screening sites to determine the test conditions of Microtox in assessing the toxicity of the sediment. In addition, a pH range of 6.0∼6.5 was established in testing pore water, aqueous extracts and organic extracts. Each extractable fraction of sediment showed different toxicities. Therefore, in order to properly examine the toxicity in the sediment, all extractable fractions of sediment samples needed to be tested with Microtox. Thus, sediment samples were additionally collected from at least 4 secondary sites within 50∼100ｍ area of the primary sampling site to reduce any variation or deviation in toxicity assessment. From all sediment toxicity data that was collected from this study, it was concluded that the Keumho river was the most polluted with the highest sediment toxicity of all the rivers analyzed and needed further detailed research on its pollution problem.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권2호
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• pp.9-15
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• 2020

This study was conducted to investigate the in situ formation of amorphous Fe oxides as a stabilization technology in As-contaminated soil. After addition of ferric nitrate and the neutralizing agent, most of extractable fractions of As in soil (i.e., SO₄^2- and PO₄^3--extractable As) was converted into As bound to amorphous Fe oxides. In addition, results of solubility bioavailability research consortium (SBRC) test indicated that a significant amount of As in untreated soil changed to a non-bioaccessible form after stabilization. The reason was attributed to the newly formed amorphous Fe oxides in the stabilized soil, which was confirmed by linear combination of fitting (LCF) using X-ray absorption spectroscopy (XAS) analysis. Interestingly, after five months of aging of the stabilized soil, ferrihydrite and schwertmannite newly formed in the soil were transformed to crystalline Fe oxides such as goethite, and further decrease in SBRC extractable fraction of As was observed. The results suggest that co-precipitated As with amorphous Fe oxides can be further immobilized with time, due to the crystallization of amorphous Fe oxides.

• 한국환경농학회지
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• 제25권3호
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• pp.236-246
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• 2006

In this study, we give insight into questionable results that can be encountered in the conventional sequential extraction of heavy metals (Cd, Cu, and Zn) from soils. Objectives of this study were to determine the extraction variability of exchangeable (EXC)-metals as using six different EXC-extractants commonly accepted, and to investigate selectivity problems with carbonates bound (CAB)-metal fraction, a buffered acetate (1.0 M NaOAc; pH 5.0) extractable-metal fraction, leading to erratic results in especially non-calcareous soils. The contents of EXC-metals were markedly varied with the different extractability of various EXC-metal extractants used. The contents of EXC-Cd fraction were ranged from 2.0 to 74.3% of total Cd content in all of the metal spiked soils studied. The contents of EXC-Zn fraction extracted with the different EXC-extractants were varied with soil types, which were from 0.4 to 3.9% of total Zn in the calcareous soils, from 7.6 to 17.9% in the acidic soil, and from 13.6 to 56.8% in the peat soil. However, the contents of EXC-Cu fraction were relatively similar among the applications of different EXC-meal extractants, 0.2 to 2.1 % of total Cu, in all soils tested. Also, these varied amounts of EXC-metal fractions, especially Cd and Zn, seriously impacted the contents of subsequent metal fractions in the procedure. Furthermore, the CAB-Cd, -Cu, and -Zn fractions extracted by the buffered acetate solution were in critical problem. That is, the buffered acetate solution dissolved not only CAB-metals but also metals that bound or occupied to subsequent fractions, especially OXD-metal fraction, in both calcareous and non-calcareous soils. The erratic results of CAB-fraction also seriously impacted the amounts of subsequent metal fractions. Therefore, the conventional sequential extraction should be reconsidered theoretically and experimentally to quantify the target metal fractions or might be progressively discarded.