• Title/Summary/Keyword: Dissolved oxygen(DO)

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A case study of monitored natural attenuation at the petroleum hydrocarbon contaminated site: I. Site characterization (유류오염부지에서 자연저감기법 적용 사례연구: I. 부지특성 조사)

  • 윤정기;이민효;이석영;이진용;이강근
    • Journal of Soil and Groundwater Environment
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    • v.8 no.4
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    • pp.27-35
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    • 2003
  • The study site located in an industrial complex has a Precambrian age gneiss as a bedrock. The poorly-developed, disturbed soils in the study site have loamy-textured surface soil (1 to 2 m) and gravelly sand alluvium subsurface (2 to 6 m) on the top of weathered gneiss bedrock. The depth of the groundwater table was about 3.5 m below ground surface and increased toward down-gradient of the site. The hydraulic conductivity of transmitted zone (gravelly coarse sand) was in the range of 5.0${\times}$10$\^$-2/∼1.85${\times}$10$\^$-1/ cm/sec. The fine sand layer was in the range of 1.5${\times}$10$\^$-3/ to 7.6${\times}$10$\^$-3/ cm/sec. and the reclaimed upper soil layer was less than 10$\^$-4/ cm/sec. Toluene, ethylbenzene, and xylene (TEX) was the major contaminant in the soil and groundwater. The average depth of the soil contamination was about 1.5 m in the gravelly sand alluvium layer. At the depth interval 2.4∼4.8 m, the highest contamination in the soil is located approximately 50 to 70 m from the suspected source areas. The concentration of TEX in the groundwater was highest in the suspected source area and a lesser concentration in the center and southwest parts of the site. The TEX distribution in the groundwater is associated with their distribution in the soil. Microbial isolation showed that Pseudomonas flurescence, Burkholderia cepacia, and Acinetobactor lwoffi were the dominant aerobic bacteria in the contaminated soils. The analytical results of the groundwater indicated that the concentrations of dissolved oxygen (DO), nitrate, and sulfate in the contaminated area were significantly lower than their concentrations in the none-contaminated control area. The results also indicated that groundwater at the contaminated area is under anaerobic condition and sulfate reduction is the predominant terminal electron accepting process. The total attenuation rate was 0.0017 day$\^$-1/ and the estimated first-order degradation rate constant (λ) was 0.0008 day$\^$-1/.

Chemical Characteristics of Water Types in the Korea Strait (해양 화학적 특성으로 본 대한해협의 수계)

  • LEE Won Jae;CHO Kyu Dae;CHOO Hyo Sang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.17 no.3
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    • pp.219-229
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    • 1984
  • Physical and chemical survey on western channel of the Korea Strait was made using oceanographic data from July 25 to July 31, 1983. Four water types were distinguished at western channel: runoff of the Nakdong River, Tsushima Current Waters, Keoje Coastal Waters, and Ulsan Coastal Waters. Influence of the Nakdong River was greater at Southern East Coast near Yeong-Do Island in Pusan than at Keoje Coast. General characteristics of these four water types were as follows : For runoff of the Nakdong River, transparency was within 3 m, water colour chinese yellow (number 11), surface temperature $18{\sim}19^{\circ}C$, salinity less than $31\%0$, surface dissolved oxygen (D.O.) $4.5{\sim}5.0ml/l$, contents of phosphate $0.25{\sim}0.5{\mu}g-at./l$ ; these values were the highest among these four water types. For Tsushima Current waters, transparency was greater than 15 m, waters color blue (number $2{\sim}4$), surface temperature about $23^{\circ}C$, salinity $32{\sim}33\%0$, and surface D.O. greater than 5,0 ml/l. Phosphate, nitrate and silicate were less than 0.25, 2.0, and $2.5{\mu}g-at./l$, respectively; these values were the lowest among these four water types. Keoje Coastal Waters had low temperature ranging $20{\sim}21^{\circ}C$ at surface, and high salinity greater than $33\%0$. D.O. was less than 5.0 ml/l, phoshpate, $0.5{\mu}g-at./l$ nitrate and silicate were less than $3.5{\mu}g-at./l$. Ulsan Coastal Waters had the lowest surface temperature among these four types; surface temperature was less than $16^{\circ}C$, salinity greater than $33.5\%0$, and D.O., phosphate and nitrate had very high values. It seems that these high values resulted from upwelling phenomena.

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Seasonal Changes of Species Composition and Standing Crop of Phytoplankton in the Ark Shell Scapharca broughtonii Farming Areas of Jinhae Bay (진해만 피조개 Scapharca broughtonii 양식장 식물플랑크톤의 종조성과 현존량의 월별변화)

  • Kim, Byoung-Hak;Min, Byeong-Hee;Choi, Nak-Joong;Oh, Bong-Se;Park, Ki-Yeol;Min, Kwang-Sik
    • Journal of Aquaculture
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    • v.21 no.3
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    • pp.157-166
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    • 2008
  • Species composition and standing crop of phytoplankton were investigated in the ark shell Scapharca broughtonii farming areas from March, 2006 to February, 2007 in Jinhae Bay. Water temperature ranged from 7.56 to $25.90^{\circ}C$, salinity from 13.74 to 34.78 psu, dissolved oxygen from 4.13 to 13.20 mg/L, chlorophyll $\alpha$ from 2.77 to 104.98 $mg/m^2$ and pH from 7.83 to 8.65. Dominant species was Nitzschia and Rhizosolenia from March to May, Skeletonama costatum and Prorocentrum from June to August, Skeletonama costatum, Thalassiosira, Chaetoceros from September to November and Thalassiosira, Chaetoceros from December to February. Colonial diatoms were more dominant than the single cell diatoms. Standing crop was the highest in July at three stations. Standing crop of Skeletonama costatum was the highest as 1,760.0 cells/mL at St. 1, 1,075.2 cells/mL at St. 2 and 698.4 cells/mL at St. 3 in July.