• Title/Summary/Keyword: concentration distributions

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Distribution Characteristcs of Organophosphorous Pesticides in Asan Bay, Korea in Summer 2006 (2006년도 하계 아산만의 유기인계 농약의 분포 특성)

  • Choi, Jin-Young;Lee, Sung-Gyu;Yang, Dong-Beom;Hong, Gi-Hoon;Shin, Kyoung-Hoon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.15 no.1
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    • pp.1-9
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    • 2009
  • Distribution characteristics of organophosphorous pesticides (OPs) were studied over the period from May to September, 2006 in Asan Bay, Korea. During the study period, 28 kinds of organophosphorous pesticides dissolved in surface water and adsorbed on suspended particle were measured. In the surface water, the dominant OPs were IBP and DDVP, and the concentration were in the ranges from not detected to 2014.4 ng/L for IBP and 3.2 to 696.3 ng/L for DDVP. The highest concentrations of OPs in the surface waters in Asan Bay appeared in July and August showing that seasonal distributions of OPs depend on application time and precipitation. The concentrations of OPs generally decreased with the increase of distance from the mouth of Asan Bay, implying progressive dilution of pesticides in the estuarine system. OPs residue in Asan Bay was relatively higher than in other area of Korea. The concentrations of the observed OPs concentrations did not exceed the seawater quality standard of Korea. DDVP, IBP, Diazinon, Phorate, Azinphos ethyl and Chlorfenvinfos had higher adsorption capacity onto suspended particle than the other OPs. In the study area, adsorption coefficients $(K_d)$ of OPs were closely related to the Log $K_ow$ of each compound.

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Characteristic Occurrence and Distributions of Pharmaceuticals in the Nakdong River (낙동강 수계 내 의약물질 발생 및 분포 특성)

  • Lee, Heon-Jun;Kim, Hee-Young;Kim, Ki Yong;Yang, Duk-Seok;Lee, Injung;Lim, Young-Kyong;Kim, Jae-Hyuk;Oh, Jeong-Eun
    • Journal of Korean Society of Environmental Engineers
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    • v.39 no.7
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    • pp.403-411
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    • 2017
  • In this study, the occurrence and temporal variation of eight pharmaceuticals comprising antibiotics (clarithromycin, sulfathiazole, sulfamethazine, sulfamethoxazole, trimethoprim), scabicide (carbamazepine) and nonsteroidal anti-inflammatory drugs (acetylsalicylic acid, naproxen) in main stream and its tributary of the Nakdong River basin, were investigated. Concentrations of the target compounds ranged from $1.076{\mu}g/L$. The highest average concentration was observed for clarithromycin ($0.0316{\mu}g/L$), followed by sulfamethazine ($0.0170{\mu}g/L$), sulfamethoxazole ($0.0161{\mu}g/L$), naproxen ($0.0129{\mu}g/L$), carbamazepine ($0.0093{\mu}g/L$), acetylsalicylic acid ($0.0047{\mu}g/L$), sulfathiazole ($0.0024{\mu}g/L$) and trimethoprim ($0.0022{\mu}g/L$). The decreasing pattern of pharmaceutical concentrations was observed along with Nakdong River and the higher concentrations in downstream were observed than those in upstream. There was no temporal variation of the target compounds although the highest level was found in February. The calculated hazard quotients (HQs) for eight pharmaceuticals were below 1, indicating no environmental hazard in Nakdong River. However, further monitoring is still needed due to the other pharmaceuticals widely used in Korea.

Improvement of Bioavailability for Lovastatin using Self-microemulsifying Drug Delivery System (미세유화약물송달시스템을 이용한 로바스타틴의 생체이용률 향상)

  • Yoon, Bok-Young;Kang, Bok-Ki;Jeung, Sang-Young;Lee, Young-Won;Lee, Si-Beum;Hwang, Sung-Joo;Yuk, Soon-Hong;Khang, Gil-Son;Lee, Hai-Bang;Cho, Sun-Hang
    • Journal of Pharmaceutical Investigation
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    • v.32 no.4
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    • pp.267-275
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    • 2002
  • A self-microemulsifying drug delivery system (SMEDDS) was developed to increase the dissolution rate, solubility, and ultimately bioavailability of a poorly water soluble drug, lovastatin. SMEDDS was thε mixtures of oils, surfactants, and cosurfactants, which emulsify under conditions of gentle agitation, similar to those which would be encountered in the gastro-intestinal (GI) tract. Various types of self-emulsifying formulations were prepared using four types of oil (Capryol 90, Lauroglycol 90, Labrafil M 1944 CS and Labrafil M 2125), two surfactants (Cremophor EL and Tween 80), and three cosurfactants (Carbitol, PEG 400 and propylene glycol). Thε efficiency of emulsification was studied using a laser diffraction size analyzer to determine particle size distributions of the resultant emulsions. Optimized formulations selected for bioavailability assessment were Carpryol 90 (40%), Cremophor EL (30%) and Carbitol (30%). SMEDDS containing lovastatin (20 mg and 5 mg) were compared to a conventional lovastatin tablet $(Mevacor^{\circledR},\;20\;mg/tab)$ by the oral administration as prefilled hard gelatin capsules to fasted beagle dogs for in vivo study. The arεa under the serum concentration-time curve from time zero to the last measured time in serum, $AUC_{0{\rightarrow}24h}$, was significantly greater in SMEDDS, suggesting that bioavailability increase 130% and 192% by the SMEDDS, respectively. The self-emulsifying formulations of lovastatin afforded the improvement in absolute oral bioavailability relative to previous data of lovastatin tablet formulation. These data indicate the utility of dispersed self-emulsifying formulations for the oral delivery of lovastatin and potentially other poorly absorbed drugs.

The origin of dissolved inorganic nutrients by Kuroshio Intermediate Water in the eastern continental shelf of the East China Sea (동중국해 외대륙붕 저층수의 영양염 기원)

  • Chung Chang Soo;Hong Gi Hoon;Kim Suk Hyun;Kim Yong Il;Moon Duk Soo;Park Jun Kun;Park Yong Chul;Lee Jae Hak;Lie Heung Jae
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.3 no.3
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    • pp.13-23
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    • 2000
  • The distributions of dissolved inorganic nutrient contents were investigated along transection line J (30° N) in the eastern East China Sea in December 1993 and August 1994, respectively. The concentrations of nitrate and silicate in the Kuroshio Surface Water (KSW) with high temperature and high salinity were low below 2μM and 5μM, respectively. However, these were increased sharply with depth and ranged from 20 to 40, 45 to 100μM, respectively, in the Kuroshio Intermediate Water (KIW). The relationship between temperature and nutrients suggests that Kuroshio Intermediate Water with rich nutrients were intruded into the bottom water of the outer continental shelf in the East China Sea. The bottom water of the outer continental shelf was made of two end-members mixing; nutrient depleted warm water and nutrient enriched cold water. Based on temperature, salinity and silicate concentration, the nutrients in the bottom water of the outer continental shelf suggusted to be supplied through the vertical mixing of Kuroshio subsurface water in the depth range of 100~400m. Upwelled nutrient rich water appears to be a important source of nutrients for primary production in the continental shelf area of the East China Sea.

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Size Distributions of Trace Elements in Airborn Particulates Collected using Drum impactor at Gosan, Jeju Island : Measurements in Springtime 2002 (DRUM impactor를 이용한 대기 입자상 물질 중 원소성분의 입경분포 특성 : 제주도 고산지역의 2002년 봄철 (3.29-5.30) 측정 연구)

  • 한진석;문광주;류성윤;안준영;공부주;홍유덕;김영준
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.4
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    • pp.555-569
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    • 2004
  • Size -segregated measurements of aerosol composition using 8-stage DRUM impactor are used to determine the transport of natural and anthropogenic aerosols at Gosan site from 29 March to 30 May in 2002. Separation of ambient aerosols by DRUM impactor offers many Advantages over other standard filtration techniques. Some of the most important advantages are the ability to segregate into details by particle tire, to better preserve chemical integrity since the air stream doesn't pars through the deposit, to collect samples as a function of time, and to have a wide variety of impaction surfaces available to match analytical needs. Although the transport of Yellow sand is a well-known phenomenon in springtime, the result of measurement shows that not only soil dust but also anthropogenic aerosols, including sulfur, enriched trace metals such as Pb, Ni, Zn. Cu, Cr, As, Se, Br, are transported to Gosan in springtime. This study combines the size- and time-resolved aerosol composition measurements with isentropic, backward air-mass trajectories in order to identify some potential source regions of anthropogenic aerosols. As a result, during the NYS period, the average concentration of PM$_{10}$ was 46$\mu\textrm{g}$/㎥, Si, Al. S, Fe, Cl, K, Ca were higher than 1,000 ng/㎥ and Ti was about 100 ng/㎥. The concentrations of Zn, Mn, Cu. Pb, Br, Rb, V, Cr, Ni. At, Se ranged between 1 and 70 ng/㎥. More than 50% typical soil elements, tuck as Al, Si, Fe, Cd. Ti, Cr, Cu, Br. were distributed in a coarse particle range(5.0-12${\mu}{\textrm}{m}$). In other hand, anthropogenic pollutants, luck as S, N, Vi, were mainly distributed in a fine particle range (0.09-0.56${\mu}{\textrm}{m}$). During the YS period, PM$_{10}$ increased about 8 times than NYS period, and main soil elements, such as Al, Si, S, K, V, Mn, Fe also doubled in coarse particle range (1.15-12${\mu}{\textrm}{m}$). But Zn, As, Pb, Cu and Se, which distributed in the time aerosols (0.09-0.56${\mu}{\textrm}{m}$), were on the same level with or decreased than NYS period. Finally. except the YS Period, coarse particles (2.5-12${\mu}{\textrm}{m}$) are inferred to be influenced by soil, coal combustion, waste incineration, ferrous and nonferrous sources through similar pathways with Yellow Sand. But fine particles have different sources, such as coal combustion, gasoline vehicle, biomass burning, oil or coal combustion, nonferrous and ferrous metal sources, which are transported from China, Korea peninsula and local sources.ces.

Analysis of Oceanographic Condition in the Cheju Strait, the Korea Strait and the Mixed water area Between the two Regions in Early June in 1995 (1995년 6월 초순 제주해협과 대한해협 입구 해역에서의 해황 분석)

  • CHOI Young-Chan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.2
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    • pp.296-301
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    • 1998
  • The physical and chemical characteristics were examined in the southern sea of Korea including the Cheju Strait, and the entrance of the Korea Strait in the period of May 30 to June 8, 1995. The results are as follows. Firstly, the variation ranges of the temperature and salinity at the Cheju Stratit during 24 hours observation were larger in the surface layer than that in the deep layers. Secondly, daily variations of nutrients show that total inorganic nitrogen, phosphate phosphorous, and silicate silicon concentration are higher at night than at day. Thirdly, water temperature and salinity distributions show highest values at the entrance of Korea Strait, which is thought to be influenced directly by Tsushima Warm Current, while they show the lowest values in Cheju Strait. This means that the surface waters in Korea Strait are greatly influenced from the entrance of Korea Strait and bottom waters is greatly influenced from Cheju Strait. Fourthly, nutrients distribution shows highest values in Korea Strait but dissolved oxygen shows lowest values in the area. These seem to be caused by the oxygen consumption used in the inorganization of nutrients to decompose organisms and the liquidation of nutrients.

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Distribution of Persistent Organic Pollutants (POPs) in Different Sizes of Particles in the Ambient Air of the Pyeongteak Area (평택지역 대기 중 먼지 입경별 잔류성유기오염물질 분포특성 연구)

  • Kim, Dong-Gi;Woo, Jung-Sik;Kim, Yong-Jun;Jung, Hye-Eun;Park, Ju-Eun;Cho, Duck-Hee;Moon, Hee-Chun;Oh, Jo-Gyo
    • Journal of Environmental Health Sciences
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    • v.46 no.2
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    • pp.192-203
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    • 2020
  • Objectives: The concentration distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenlys (dl-PCBs), and polycyclic aromatic hydrocarbons (PAHs) in fine particles were investigated to provide basic data on POP behavior and composition analysis. Methods: The concentrations of PCDD/Fs, dl-PCBs, and PAHs by particle size were evaluated for TSP, PM10, and PM2.5. Also, fine dust component analysis and factor analysis were performed to identify the source of PCDD/Fs. Results: The particle size distribution was found to account for 24.3% of >10 ㎛, 14.5% of 2.5-10 ㎛, and 61.2% of <2.5 ㎛. The average contributions of coarse particles (>2.5 ㎛) and fine particles (<2.5 ㎛) were PCDD/Fs 67%, dl-PCBs 66%, benzo (a) pyrene 83% and PAHs 84%, and the contributions of fine particles (<2.5 ㎛) were higher than coarse particles (>2.5 ㎛). However, the contributions of coarse particles increased in April to September with higher temperatures, while those of fine particles increased in February to March with lower temperatures. Conclusions: Low chlorinated (4Cl-5Cl) PCDD/Fs were more adsorbed compared to coarse particles due to the influence of pollutant migration from particulate to gas phase according to temperature rise, whereas high chlorinated (6Cl-8Cl) PCDD/Fs were more adsorbed compared to fine particles. PCDD/Fs sources were assessed to be major sources of emissions, such as incineration facilities and/or open burning.

Environmental Characteristics and Distributions of Marine Bacteria in the Surface Sediments of Kamak Bay in Winter and Summer (동 . 하계 가막만 표층 퇴적물의 환경특성과 해양미생물의 분포)

  • Lee, Dae-Sung;Kim, Yun-Sook;Jeong, Seong-Yun;Kang, Chang-Keun;Lee, Won-Jae
    • Journal of Environmental Science International
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    • v.17 no.7
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    • pp.755-765
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    • 2008
  • To investigate correlation between the distribution of marine bacteria and environmental characteristics in the surface sediments of Kamak Bay, chemical oxygen demand(COD), acid volatile sulfide(AVS), ignition loss(IL), total organic carbon(TOC), and total organic nitrogen(TON) were measured and analyzed at 7 stations in winter and summer. In winter, COD and AVS ranged from 13.45 mg/g to 30.06 mg/g(average: 23.58 mg/g) and from 0.03 mg/g to 1.04 mg/g(average: 0.63 mg/g), respectively. IL, TOC, and TON ranged from 8.03% to 11.41%(average: 9.41%), from 1.17% to 2.10%(average: 1.62%), and from 0.09% to 0.18%(average 0.15%), respectively. In summer, COD, AVS, IL, TOC, and TON ranged from 14.06 mg/g to 32.19 mg/g(average: 24.71 mg/g), from 0.03 mg/g to 1.11 mg/g(average: 0.66 mg/g), from 9.00% to 12.15%(average: 10.96%), from 1.27% to 2.12%(average 1.77%), and from 0.12% to 0.19%(average: 0.16%), respectively. These values were relatively higher than those in winter. Kamak Bay had high C/N ratio that might be resulted from the input of terrestrial sewage and industrial wastewater. The number of marine viable bacteria was $8.9{\times}10^4\;cfu/g$ in winter and $9.7{\times}10^5\;cfu/g$ in summer. The most abundant species were Pseudomonas spp., Flavobacterium spp., and Vibrio spp, in the surface sediments of Kamak Bay. It was found that the concentration of organic matters and viable bacterial cells in the inner part were relatively higher than those in the outer of Kamak Bay. The distribution of viable bacterial cells was closely influenced by environmental factors.

Future Projection of Changes in Extreme Temperatures using High Resolution Regional Climate Change Scenario in the Republic of Korea (고해상도 지역기후변화 시나리오를 이용한 한국의 미래 기온극값 변화 전망)

  • Lee, Kyoung-Mi;Baek, Hee-Jeong;Park, Su-Hee;Kang, Hyun-Suk;Cho, Chun-Ho
    • Journal of the Korean Geographical Society
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    • v.47 no.2
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    • pp.208-225
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    • 2012
  • The spatial characteristics of changes in extreme temperature indices for 2070-2099 relative to 1971-2000 in the Republic of Korea were investigated using daily maximum (Tmax) and minimum (Tmin) temperature data from a regional climate model (HadGEM3-RA) based on the IPCC RCP4.5/8.5 at 12.5km grid spacing and observations. Six temperature-based indices were selected to consider the frequency and intensity of extreme temperature events. For validation during the reference period (1971-2000), the simulated Tmax and Tmin distributions reasonably reproduce annual and seasonal characteristics not only for the relative probability but also the variation range. In the future (2070-2099), the occurrence of summer days (SD) and tropical nights (TR) is projected to be more frequent in the entire region while the occurrence of ice days (ID) and frost days (FD) is likely to decrease. The increase of averaged Tmax above 95th percentile (TX95) and Tmin below 5th percentile (TN5) is also projected. These changes are more pronounced under RCP8.5 scenario than RCP4.5. The changes in extreme temperature indices except for FD show significant correlations with altitude, and the changes in ID, TR, and TN5 also show significant correlations with latitude. The mountainous regions are projected to be more influenced by an increase of low extreme temperature than low altitude while the southern coast is likely to be more influenced by an increase of tropical nights.

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Impact of Seawater Inflow by the Operation of Sluice Gates on the D.O and pH in the Lake Shihwa, Korea (시화호 배수갑문 운용에 따른 용존산소와 pH 변화)

  • Choi, Jung-Hoon;Kim, Mi-Ock
    • Journal of the Korean earth science society
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    • v.22 no.3
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    • pp.195-207
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    • 2001
  • The variations of D.O and pH due to the inflow of seawater by sluice gates operation were observed in the Lake Shihwa, Korea. The distributions of D.O and pH were investigated at 11 stations during Feburary 1997 to July 1998. The concentration of D.O before gate operation was 10 mg/l or more all over the watershed, yet 5 mg/l or less in the water layers of 11 m or below from March to June 1997. Anoxic layer appeared in June 1997 and expanded during rainy season. The anoxic layer in the lake depleted the oxygen in seawater as seawater was inflowed. It may be interpreted that the phenomenon comes from the contact of seawater to lower fresh water. The contact of seawater in pH 7.8 to 8.2 to lower water less than pH 7.4 enhanced to oxidize. After January 1998, D.O of the lake increased over 10 mg/l and the stratification was weakened. As a result, it may be concluded that the best way to improve the water qualities is to increase the amount of seawater inflow and outflow so as not to be generated pycnocline in summer.

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