• Environmental Analysis Health and Toxicology
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• 제21권3호
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• pp.255-266
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• 2006

Soil organic matter (OM) is well documented for its capacity to retain persistent organic pollutants (POPs) and thus is important in dictating the environmental partitioning of POPs between media such as air, water, and soil. Black carbon (BC) is a small component of OM and exhibitt a 10$\sim$100 times greater sorption capacity of POPs than humified OM. Furthermore, due to the inherent long environmental life time of BC, a result of its resistance to physical and biological degradation, POPs can continue to accumulate in BC over a long period of time. The unique properties of BC have been of particular interest over the last 30 years and have resulted in broad research being conducted into its effects of POP cycling in atmospheric, oceanographic and soil matrices. The results of such studies have proved valuable In providing new research initiatives into the role of BC in the cycling of hydrophobic organic compounds (HOCs) as well as giving further insight into the long range atmospheric transport (LRAT) potential and subsequent risk assessment criteria for persistent organic pollutants (POPs). In this report, we introduce a novel study examining the relationships between BC and OM with respect to their POP sorption capacity and discuss the role of BC in influencing the environmental regulation of organic pollutants.

• 한국환경과학회지
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• 제11권3호
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• pp.227-234
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• 2002

Laboratory experiments were conducted to examine the behavior of metalaxyl in environment which was used as pesticide in green soil of golf course and as functions of the characteristics of adsorption, desorption and degradation in soil texture and organic matter contents. Acid water containing metalaxyl was conducted to evaluate the effects on adsorption, desorption and degradation. The adsorption of metalaxyl played more significant role in organic contents than clay contents, and pH Increases more pH 2.5 than pH 5.6. The desorption of metalaxyl from contaminants soil decreased higher organic contents LS-soil than S-soil, but the desorption amount of metalaxyl increased more pH 5.6 than pH 2.5. The rate of degradation of metalaxyl in green soil environmental increased higher organic contents LS-soil than S-soil and decreased more pH 2.5 than pH 5.6. These results indicated that the behavior of metalaxyl of the green soil was affected the soil texture of the golf course. Increasing of organic contents, the adsorption amount of metalaxyl on soil increased. Moreover the decrease of the pH of solution increased adsorption amounts and decreased desorption amounts. As the results, the transportation of metalaxyl in soil decreased the acidic rates. The acidification of soil by the acid rain increased the adsorption amount of metalaxyl, but the degradation of metalaxyl decreased. Therefore, it is possible to sustain contamination in run-off the stream and ground water by residuals in soil.

• 한국물환경학회지
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• 제30권6호
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• pp.605-611
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• 2014

This research was carried out to examine the concentration and fate of dissolved organic matter due to the increased detention time in middle and down stream of the Nakdong River. Aldo the characteristics of biodegradation of DOM were investigated according to the various water sources. The approaches used to characterize DOM biodegradability include the changes in DOC concentration and DOM fraction. Long-term biodegradation test for each organic source was also conducted. As the result, maximum 50% of DOC was reduced during the first 30 days of biodegradation tests. After 30 days, biodegradation of organic matter was continuously progressed, as showing continuous reduction of DOC. While DOC concentration was reduced, SUVA values for the organic matters were increased. Properties of dissolved organic matter by water sources also showed decreasing hydrophilic components while showing increased hydrophobic components. The more rapid reduction of the hydrophilic components than hydrophobic components might be due to the preferential degradation of the hydrophilic components by microorganisms during biodegradation process.

• Journal of the korean society of oceanography
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• 제31권3호
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• pp.134-143
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• 1996

Sediment cores were collected from one site each in Amursky and Ussuriysky Bays in the Peter the great Bay for $^{210}Pb$, org C, N, biogenic Si, ${\delta}^{13}$C and ${\delta}^{15}$N analysis to elucidate the processes of biogenic particulate matter accumulation and early diagenetic change in the upper sediment column. Biogeochemistry at the core sites of both bays shows differences in sedimentation rate, sediment mixing, and diagenetic processes of particulate biogenic matter. Sedimentary organic matter at the core sites in both bays appeared to be largely derived from marine origin. Sedimentation rates are 173 and 118 mg $cm^{-2}$ $yr^{-1}$(0.13 and 0.11 cm $yr^{-1}$) in Amursky and Ussuriysky Bays, respectively. The surface mixed layer in the core top was present in Amursky Bay but not in Ussuriysky Bay. At the core site in Amursky Bay, incorporation of biogenic particulate matter into the sediment from the overlying waters is 236, 19, 142 mmol $cm^{-2}$ $yr^{-1}$ for organic C, N, and biogenic Si, respectively. Of which about 70${\%}$ of organic C and biogenic Si are degraded within the upper 25 cm sediment and the rest are buried at 25 cm sediment horizon. At the core site in Ussuriysky Bay, incorporation of biogenic particulate matter into the sediment from overlying waters is 164, 18, 76 mmol $cm^{-2}$ $yr^{-1}$ for organic C, N, and biogenic Si, respectively. Of which less than 50${\%}$ of organic C and biogenic Si are degraded within the upper 25 cm sediment and the remainder are buried at 25 cm sediment horizon. This large difference of degradation of biogenic matter in the upper 25 cm sediment column appears to be resulted from the difference in sediment mixing rates between the two cores.

• Asian-Australasian Journal of Animal Sciences
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• 제2권4호
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• pp.583-590
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• 1989

Increasing levels of ammonia-N in the rumen fluid used for in vitro incubation were achieved by supplementation of the ration of the donor cows with urea and by addition of urea either with or without glucose to the rumen fluid after collection. The ration of the donor animals consisted of wheat straw (80%) and maize silage (20%). During the second half of the experiment the basal ration was supplemented with a mineral mixture. Wheat straw, Guinea grass and two rice straw varieties were incubated with the various kinds of rumen fluid. Parameters studied were: solubility, apparent organic matter disappearance after 48 hours of incubation ($OMD_{48}$), rate of organic matter degradation from 0 to 24 hours of incubation ($k_1$) and from 24 to 95 hours ($k_2$). The concentration of ammonia-N in the rumen fluid at which 95% of the maximal $OMD_{48}$ and k1 were reached (88.2 and 100.0 mg/l) were independent of the feed. With regard to the $k_2$ the required ammonia-N concentration to reach 95% of the maximal $k_2$ differed per feed. Mineral supplementation increased the OMD48 and $k_1$, but not the solubility and $k_2$. Glucose addition in combination with urea had no beneficial effect compared to urea supplementation alone.

• 멤브레인
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• 제17권3호
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• pp.244-253
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• 2007

광촉매 반응이 자연유기물에 의한 나노여과막의 오염에 미치는 영향을 살펴보았다. 광촉매 분해공정은 자연유기물의 분해와 변형에 효율적이었으며 이산화티타늄과 고정화 비드를 광촉매로 사용하였다. 광촉매적 특성을 비교하기 위하여 칼슘 이온 존재 시의 휴민산의 광분해를 모델 반응으로 설정하였다. 광분해 전에는 치밀한 막오염층이 형성되어 막오염을 가속화시킨 반면, 광분해 후에는 막오염이 크게 감소하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제1권1호
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• pp.21-25
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• 1988

The rumen degradability of rice straw (untreated, urea-sprayed, urea-treated), grasses (Panicum maximum, Pennisetum clandestinum) and rice bran was compared. The mean in vivo organic matter digestibility of the untreated (US), urea-supplemented (SS) and urea-ammonia treated (TS) rice straw were 50.9, 53.9 and 57.4%, respectively. Rice bran contained extremely high levels of acid-insoluble ash (25.2% DM), and its OMD was 36.1%. Grasses had OMD values around 66%. Degradability measurements were performed with buffaloes using the nylon bag technique. The organic matter (OM) disappearance data were fitted to an model which was used to describe degradation pattern. The mean potentially degradable fraction for US, SS and TS was 61.5, 61.9 and 69.4%, respectively. Urea-ammonia treatment increased both the amount of OM degraded and the rate at which it was degraded in the rumen. Both grasses had similar values for degradable fraction (around 65%) and for rate constant for degradation (0.04). Rice bran contained high proportions of readily soluble material (23.9%), but the degradable OM fraction was only 13.2%. The low quality of rice bran is attributed to the contamination of rice hulls during processing.

• Asian-Australasian Journal of Animal Sciences
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• 제15권7호
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• pp.974-981
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• 2002

Faba beans (vicia faba) (FB) and lupin seeds (Lupinus Albus) (LS) were dry roasted at three temperatures (110, 130, $150^{\circ}C$) for 15, 30 or 45 min to determine the effects of dry roasting on rumen degradation of crude protein and starch free organic matter ($^{PSF}OM$). Rumen degradation characteristics of $^{PSF}OM$ were determined by the nylon bag incubation technique in dairy cows fed 60% hay and 40% concentrate. Measured characteristics of $^{PSF}OM$ were undegradable fraction (U), degradable fraction (D), soluble fraction (S), lag time (T0), and the rate of degradation (Kd). Based on the measured characteristics, rumen availability ($RA^{PSF}OM$) and bypass $^{PSF}OM$ ($B^{PSF}OM$) were calculated. Dry roasting did not have a greater impact on rumen degradation characteristics of $^{PSF}OM$ (p>0.05). S varied from 32.1 (raw) to 30.0, 27.8, 30.8% (LS) and 15.4 (raw) to 14.4, 20.8, 20.9% (FB); D varied from 65.4 (raw) to 66.3, 66.9, 55.9% (LS) and 54.9 (raw) to 55.0, 51.0, 64.7% (FB); U varied from 2.6 (raw) to 7.3, 7.0, 7.7% (LS) and 29.7 (raw) to 30.6, 28.2, 14.4% (FB); Kd varied from 6.0 (raw) to 7.3, 7.0, 7.7% (LS) and 22.4 (raw) to 24.4, 21.1, 7.9% (FB); $B^{PSF}OM$ varied from 35.5 (raw) to 33.8, 36.6, 38.2% (LS) and 41.3 (raw) to 41.5, 39.7, 47.6% (FB) at 110, 130 and $150^{\circ}C$, respectively. Therefore dry roasting did not significantly affect $RA^{PSF}OM$, which were 353.7, 367.9, 349.6, 336.9 (g/kg DM) (LS) and 12.82, 127.0, 133.7, 117.1 (g/kg DM) (FB) at 110, 130 and $150^{\circ}C$, respectively. These results alone with our previously published reports indicate dry roasting had the differently affected pattern of rumen degradation characteristics of various components in LS and FB. It strongly increased bypass crude protein (BCP) and moderately increased starch (BST) with increasing temperature and time but least affected $^{PSF}OM$. Such desirable degradation patterns in dry roasted LS and FB might be beneficial to the high yielding cows which could use more dry roasted $^{PSF}OM$ as an energy source for microbial protein synthesized in the rumen and absorb more amino acids and glucose in the small intestine.

• 상하수도학회지
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• 제10권4호
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• pp.111-118
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• 1996

Effects of $CO_2$ partial pressure($pCO_2$) on the characteristics of methane production rate and organic matter degradation in anaerobic digestion were investigated by using anaerobic chemostat type reactors at $35{\pm}1^{\circ}C$, at the HRT of 7days. The $pCO_2$ of the reactors was controlled in the range from 0.1 to 0.8 atm. Since the $pCO_2$ in an uncontrolled condition was about 0.4atm, $N_2$ was added for the reactors controlled of $pCO_2$ of between 0.1 and 0.4atm. At $pCO_2$ of 0.5 atm, the methane production rate was approximately 20% more that in an uncontrolled condition of $pCO_2$. Based on the carbon mass balance, it was concluded that methane production was related to the increment of removal organic carbon and consumption of $CO_2$. At $pCO_2$ of 0.5atm, the methane production by the increment of removal substrates increased 13.6%, on the orther hand, hand, the methane production by the conversion of $CO_2$ to methane increased 6.4%.

• 대한환경공학회지
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• 제31권10호
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• pp.839-844
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• 2009

이 연구는 담수 퇴적물에서 주되게 일어나는 탈질(denitrification), 철 환원(iron reduction), 메탄 환원(methanogenesis) 반응이 퇴적물 유기물 분해에서 차지하는 중요도를 파악하였다. 탈질률, 철환원률, 메탄환원률 모두 식물이 존재하지 않는 Site A, 새섬매자기 군락이 서식하는 Site B, 갈대 군락이 서식하는 Site C에서 통계적으로 유의한 차이를 보였고(P < 0.05), 퇴적물 깊이에 따라서는 메탄환원률만이 유의한 차이를 보였다. 유기물 함량은 Site A, Site B, Site C 순으로 식물의 존재와 밀도 증가에 따라 증가하였다. Site A가 가장 낮은 유기물 함량을 나타냄에도 불구하고 가장 높은 탈질률과 철환원률을 나타내었고, 메탄환원률의 경우 Site C에서 가장 큰 값을 나타내었다. 유기물의 혐기성 분해가 주로 탈질, 철 환원, 메탄 환원에 의해 일어난다고 가정한다면, 한강하구의 경우 탈질이 유기물을 분해하는 가장 주된 반응임을 알 수 있었다.