• Title/Summary/Keyword: Environmental efficiency

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The Growth Characteristics and Germanium Uptake by Water Celery in Soil Treated with Germanium (게르마늄 처리 토양에서 미나리 생육 특성과 게르마늄 흡수)

  • Lee, Seong-Tae;Lee, Young-Han;Heo, Jae-Young;Hong, Kwang-Pyo;Dahlgren, Randy A.;Heo, Jong-Soo
    • Korean Journal of Environmental Agriculture
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    • v.27 no.2
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    • pp.185-190
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    • 2008
  • In order to obtain the basic information for agricultural utilization of Germanium(Ge), the growth characteristics and the germanium uptake by water celery were investigated at different concentration of germanium in soil. This experiment was carried out in the Wagner pot(1 $5,000^{-1}a$). Germanium concentrations in soil for water celery cultivation were maintained at 0.26, 25.0, 62.5, and 125.0 mg $kg^{-1}$, respectively. The treatment of over Ge 25.0 mg $kg^{-1}$ in the soil led to germanium phytotoxicity such as reduction of plant height and fresh weight. The contents of germanium in water celery were increased with the increase of germanium concentration in the soil. When water celery was cultivated from soil maintained with Ge 25.0 and 62.5 mg $kg^{-1}$, its germanium contents in plant were 89.9 and 371.6 mg $kg^{-1}$, respectively. Then, the efficiency of germanium uptake of water celery in Ge 25.0 and 62.5 mg $kg^{-1}$ maintained plots was 1.7 and 2.4%, respectively. When water celery was cultivated from soil maintained with Ge 25.0, 62.5 and 125.0 mg $kg^{-1}$, its content of amino acid was found to be 89.8, 198.4, and 318.2 mg $g^{-1}$, respectively. To investigate the effect of N fertilizer application in uptake of germanium by water celery, these were treated with nontreatment, 1.0, 1.5 and 2.0 times of N application based on soil testing for cultivation of water celery. However, the amount of the N fertilizer application did not affect the contents of germanium in the water celery. When water celery was cultivated from soil maintained with two kinds of inorganic and organic germanium 50 mg $kg^{-1}$, respectively, the content of germanium were 24.2 mg $kg^{-1}$ in the Ge-132 treatment and 11.8 mg $kg^{-1}$ in the $GeO_2$ treatment.

Kinetic and Statistical Analysis of Adsorption and Photocatalysis on Sulfamethoxazole Degradation by UV/$TiO_2$/HAP System (UV/$TiO_2$/HAP 시스템에서 Sulfamethoxazole의 흡착과 광촉매반응에 대한 동역학적 및 통계적 해석)

  • Chun, Suk-Young;Chang, Soon-Woong
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.5
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    • pp.5-12
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    • 2012
  • Antibiotics have been considered emerging compounds due to their continuous input and persistence in environment. Due to the limited biodegradability and widespread use of these antibiotics, an incomplete removal is attained in conventional wastewater treatment plants and relative large quantities are released into the environment. In this study, it was determined the adsorption and photocatalysis kinetics of antibiotics (Sulfamethoxazole, SMX) with various catalyst (Titanium dioxide; $TiO_2$, Hydroxyapatite; HAP) conditions under UV/$TiO_2$/HAP system. In addition, the statistical analysis of response surface methods (RSM) was used to determine the effects of operating parameters on UV/$TiO_2$/HAP system. $TiO_2$/HAP adsorbent were found to follow the pseudo second order reaction in the adsorption. In the result of applied intrapaticle diffusion model, the constants of reaction rate were $TiO_2$=$0.064min^{-1}$, HAP=$0.2866min^{-1}$ and $TiO_2$/HAP=$0.3708min^{-1}$, respectively.The result of RSM, term of regression analysis in analysis of variance (ANOVA) showed significantly p-value (p<0.05) and high coefficients for determination values($R^2$=96.2%, $R^2_{Adj}$=89.3%) that allowed satisfactory prediction of second order regression model. And the estimated optimal conditions for Y(Sulfamethoxazole removal efficiency, %) were $x_1$(initial concentration of Sulfamethoxazole)=-0.7828, $x_2$(amount of catalyst)=0.9974 and $x_3$(reation time)=0.5738 by coded parameters, respectively. According to the result of intraparticle diffusion model and photocatalysis experiments, it was shown that the $TiO_2$/HAP was more effective system than conventional AOPs(advanced oxidation processes, UV/$TiO_2$ system).

An Evaluation on the Operating of Fisheries Extension Services (어촌지도사업의 평가)

  • 최정윤
    • The Journal of Fisheries Business Administration
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    • v.17 no.2
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    • pp.65-106
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    • 1986
  • 1, The Purpose of Study This is a study on the Evaluation of the operating of Fisheries Extension Services of Korea, for performing the activities such as guiding fisheries technique as well as offering industrial information to the fishermen in fishing village. By doing so, the Fisheries Extension Sevices(FES) can materialize the continued growth of fisheries, the social and economic development of fishing village, and the increase in income by enhancing the knowledge level of Fishermen, etc. In performing fisheries policy, this activity plays a great role on the research and development activity, and it has become practical since 1976 in Korea. In order to meet immediately with the problem of fisheries technical innovation and rapid environmental changes surrounding the fisheries, the fishermen should not only enhance their scientific and comprehensive capacity in fisheries technique but abtain various effective information. Generally, as most of all the fishemen are poor in the managerial structure and scattered in fishing villages, they have little opportunity in the contact of information. As a result, it is nessessary for the FES to perform the fishing business by the extension service officials who has received special training and acquired fisheries know-how in these fields. And yet, FES is under the unfullfilled circumstance in such factors as manpower, technical know-how, equipment, and the service system etc., which is required in promoting the social, economic development of fishing village and in resolving the high technique demand of fisherman. This study on the fisheries extension services have been studied from those backgrounds. 2. Research Method The data of collecting methods which were necessary in carrying out this study was adopted by the questionaire research on the present extension service activity, through the subject of the extension services (driving agency of the work and the officials), the object(fishemen) and the 3rd observers to the extension services (the authorities concerned). The research sample was taken by the sampling extraction of total 1, 774 men from the above 3 groups. And the research was carried out from August, 1986 to October, 1986, supported from the Fisheries Extension Office (FEO) located in field during the research process. In this study, the levels of the extension operating were determined and estimated in accordance with the extension service method, morale of extension service officials and the extension service system, etc. through the collected data of the research questionaire paper. And based on this result, the essential conditions of the extension services were grasped, and also we tried to present the various activity plan necessary to promote the operating of the extension services. The questionaire research data was calculated by the computer center of National Fisheries University of Pusan, and the total result was again tried on the one demension analysis along with two dimension analysis to search out the relativity between the questionaire, and the statistical test was done $\chi$$^2$test in significance level of l~5%. 3. Contents of Study This study consists of 7 chapters and the contents are as follows : Chapter I : The object and method of the study Chapter II : The assessment and analysis of the extension services Chapter III : The contents and method of the extension services Chapter IV : Analysis of the essential conditions for the extension services Chapter V : The evaluation of activities of extension services Chapter Ⅵ : Conclusion.4. Results and RecommendationTherefore, the results of this study estimated by logical process and analysis are as follows : 1) Most of Korean fishing villages and coastal fishermen have shown much concerns about fisheries technique and social changes, thus many of them were confronted with new problems on how to adapt and to meet changes. 2) Majority of fishermen estimated FEO as an organization of specific technologies with all the thing concerning the fisheries technique in general. Therefore the fishermen wanted to utilize the FEO as an adaptable method for the modern fisheries techniques as well as the environmental changes. 3) In contrast with the fast changes of the fisheries technique, the complexity and variety of technical system and the broadness of fishing village and fishermen, it was revealed that the necessary factors such as the facilities, manpower, budget, and the level of applying techniques of the FEO located in field were highly insufficient. Accordingly, the guiding efficiency was low and the extension services did not provide full solution to the various request from fishermen. 4) It is possible to classify the activation factor for the extension service into two large dimension ; personal dimension relevant to guidance officials and work dimension relevant to the organization. And it was found that the activation level of the work dimension was far lower than the personal dimension between them. So, the activation should be done first in the dimesion to promote the activation of the extension services. 5) The extension services officials are now demoralized in general, thus it is necessary to take reality into consideration : the expense of activity, the adequate endowment of activity scope and the reasonable operation of the position class, etc to enhance its morale. However, in order to do the FES activation, first of all, the systems should be established which is lain unsettled stage until now. And there must be change in the understanding of government i.e. the fisheries extension services are the essential policy subject to build up the base of fisheries growth and modernize the fisheries management. And it should be driven positively with the recognition of the "lasting project".g project".uot;.

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Variation of Pesticide Residues in Strawberries by Washing and Boiling Processes (딸기의 세척 및 가공 과정에 따른 농약 잔류량 변화)

  • Kwak, Se-Yeon;Lee, Sang-Hyeob;Jeong, Hye-Rin;Nam, Ae-Ji;Sarker, Aniruddha;Kim, Hyo-Young;Lim, Chae-Uk;Cho, Hyun-Jeong;Kim, Jang-Eok
    • Korean Journal of Environmental Agriculture
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    • v.38 no.4
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    • pp.281-290
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    • 2019
  • BACKGROUND: As the demand for strawberries increases, people are paying attention to food safety in strawberry, especially pesticide residues. To remove the pesticides from strawberry, various washing and processing technique in households are additionally required. METHODS AND RESULTS: Strawberries were washed with water, detergent, alcohol, and ultrasonication and processed to strawberry jam. The mean reduction efficiency according to the washing solvent and method was found to be higher in the order of detergent (42.5%) > alcohol (41.7%) > water (41.3%) > ultrasoniation with alcohol (40.2%) > ultrasoniation with water (38.6%) > ultrasoniation with detergent (36.9%), but there was no significant difference among the treatments. The residue levels of pesticides during processing to jam decreased by 11.9-94.4% for etoxazole, fluopyram, procymidone, spiromesifen, and prochloraz, while the other pesticides were concentrated by boiling, or rather increased by 11.8-40.2%. However, when the residue levels were converted to residual amounts in consideration of the change in weight after processing, the residual amounts of the tested pesticides were reduced by 59.8-98.4% during processing. The processing factor (PF) were different for each pesticide, but PFs were < 1 for all washing solvents and methods, and 0.06-1.40 when processed into jam. CONCLUSION: To ensure the consumption of pesticide-free strawberry, the most efficient washing method is to immerse the strawberry in fresh water for few minutes, followed by rinsing them under running water.

Definition and Division in Intelligent Service Facility for Integrating Management (지능화시설의 통합운영관리를 위한 정의 및 구분에 관한 연구)

  • PARK, Jeong-Woo;YIM, Du-Hyun;NAM, Kwang-Woo;KIM, Jin-Young
    • Journal of the Korean Association of Geographic Information Studies
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    • v.19 no.4
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    • pp.52-62
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    • 2016
  • Smart City is urban development for complex problem solving that provides convenience and safety for citizens, and it is a blueprint for future cities. In 2008, the Korean government defined the construction, management, and government support of U-Cities in the legislation, Act on the Construction, Etc. of Ubiquitous Cities (Ubiquitous City Act), which included definitions of terms used in the act. In addition, the Minister of Land, Infrastructure and Transport has established a "ubiquitous city master plan" considering this legislation. The concept of U-Cities is complex, due to the mix of informatization and urban planning. Because of this complexity, the foundation of relevant regulations is inadequate, which is impeding the establishment and implementation of practical plans. Smart City intelligent service facilities are not easy to define and classify, because technology is rapidly changing and includes various devices for gathering and expressing information. The purpose of this study is to complement the legal definition of the intelligent service facility, which is necessary for integrated management and operation. The related laws and regulations on U-City were analyzed using text-mining techniques to identify insufficient legal definitions of intelligent service facilities. Using data gathered from interviews with officials responsible for constructing U-Cities, this study identified problems generated by implementing intelligent service facilities at the field level. This strategy should contribute to improved efficiency management, the foundation for building integrated utilization between departments. Efficiencies include providing a clear concept for establishing five-year renewable plans for U-Cities.

Remediation Design Using Soil Washing and Soil Improvement Method for As Contaminated Soils and Stream Deposits Around an Abandoned Mine (토양 세척법과 석회를 첨가한 토양 안정화 공법을 이용한 폐광산 주변 비소 오염 토양 및 하천 퇴적토 복원)

  • 이민희;이정산;차종철;최정찬;이정민
    • Economic and Environmental Geology
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    • v.37 no.1
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    • pp.121-131
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    • 2004
  • Removal efficiencies of soil washing and soil improvement processes to remediate farmland soils and stream deposits around Goro abandoned mine were investigated with batch and column experiments. For As-contaminated farm-land soils around Goro mine, batch tests to quantify As extraction rate from contaminated soils and lime treated contaminated soils were performed. The contaminated soil mixed with lime decreased As extraction rate less than one fourth, suggesting that the soil improvement method mixed with lime dramatically decrease As extraction rate. A storage dam will be constructed in the lower part of the main stream connected to Goro abandoned mine and the amount of As extracted from the bottom soils of reservoir could be the main source to contaminate water of reservoir. The decrease of As extraction amount from the bottom in reservoir, caused by the application of the soil improvement method was investigated from the physically simulated column experiment and results showed that As extraction rate decreased to one forty when 1% lime mixed soil improvement was applied to contaminated soils. For contaminated stream deposits connected Goro mine, the removal efficiency of the soil washing method was investigated with batch experiments. Hydrochloric acid, citric acid, acetic acid and distilled water were used as soil washing solution and 0.01, 0.05, 0.1, 0.5, 1.0 N of washing solution were applied to extract As. When washing with 0.05 N of hydrochloric acid or citric acid, more than 99.9% of As was removed from stream deposits, suggesting that As contaminated stream deposits around Goro mine be successfully remediated with the soil washing process. Total volumes of contaminated soils and deposits needed for remediation were calculated based on three different reme-diation target concentrations and the operation cost of soil washing for calculated soil volumes was estimated. Results from this research could be directly used to make a comprehensive countermeasure to remediate contaminated area around Goro mine and also many contaminated areas similar to this research area.

Effects of Depth and Duration of Water-logging on Growth and Yield at Transplanting and Flowering Stage in Pepper (Capsicum annuum L.) (고추(Capsicum annuum L.)의 이식기(移植期) 및 개화기(開化期) 침수처리(浸水處理) 따른 생육반응(生育反應))

  • Guh, Ja-Ock;Kuk, Yong-In
    • Korean Journal of Environmental Agriculture
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    • v.15 no.4
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    • pp.425-433
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    • 1996
  • Pepper plants were water-logged at 0, 5, 10 and 15 cm at transplanting and flowering stages under the condition of greenhouse. Treatment of water-logging times were 6, 12, 24, 48 and 120 hours. The results obtained are summarized as follows. At the transplanting stage, plant height, number of leaves, shoot and root fresh weight decreased by water-logging at 0cm for 24 hours and at 5cm or more for 6 hours. Number of fallen leaf was negligible by 12 hours water-logging at 0cm, however, its increased by more increased the water-logging depth and time. Diffusion resistance and chlorophyll content of leaf, and root activity decreased at more than 24 hours of water-logging regardless of the water-logging depth treatments. Photosynthesis and respiration rate diminished by increased the water-logging depth at 120 hours water-logging treatment. Plant diseases, mainly anthracnose(Colletotrichum) occurred in proportion to increase the depth and time of water-logging. It was not possible to control the diseases by fungicides. At the treatment of foliar spray of urea for recovery to water-logging damage, the efficiency was not found on plant height, but the number of leaves. Number of fruit and weight of fruit per plant showed no difference from no water-logging to 24 hours water-logging at 0cm, but its decreased that more than 24 hours water-logging at 0cm and more than 6 hours water-logging at 5cm or more. The averaged weight of a fruit on survival plants increased by more hours and deeper water-logging. There was positive correlation between all the investigated characteristics of growth and yield. There was, however, negative correlation between the characteristics and diffusion resistance of leaf stomata. The correlation between number of fallen leaf and averaged weight of a fruit was not significant. At flowering stage, number of fruit and weight of fruit per plant showed a similar tendency to no water-logging and by 12 hours water-logging at 0cm and 5cm, but significantly decreased at more than 24 hours water-logging from 0 to 5cm, and more than 6 hours water-logging at 10cm or more. The averaged weight of a fruit on survival plants increased by more hours and deeper water-logging except for 120 hours water-logging at all water depths.

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Ecosysteme de I′Etang de Berre (Mediterranee nord-occidentale) : Caracteres Generales Physiques, Chimiques et Biologiques

  • Kim, Ki-Tai
    • Korean Journal of Environmental Biology
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    • v.22 no.2
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    • pp.247-258
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    • 2004
  • Climatological, hydrological and planktonical research studies, measurements of primary production and photosynthetic efficiency from December 1976 to December 1978 have been carried out in two brackish lakes: Lake Etang de Berre and Lake Etang de Vaine located in the French Mediterranean coast, in the region of Carry-le-Rouet located on the north-west Mediterranean near Marseilles, and in fresh water inflows from 4 Rivers (Touloubre, Durance, Arc, Durancole) to Lake Etang de Berre. Physico-chemical parameters were measured for this study: water temperature, salinity, density, pH, alcalinity, dissolved oxygen (% saturation), phosphate, nitrate, nitrite, silicate etc. Diverse biological parameters were also studied: photosynthetic pigments, phaeopigments, specific composition and biomass of phytoplankton, primary pelagic production etc. Climatical factors were studied: air-temperature, solar-radiation, evaporation, direction (including strength) of winds, precipitation and freshwater volume of the four rivers. The changes in Lake ‘Etang de Berre’ ecosystem depend on the quality of the water in the Durance River, and on the effects of seawater near the entrance of the Caronte Canal. The water quality of the lake varies horizontally and vertically as a result of atmospheric phenomena, maritime currents and tides. The distribution of water temperatures is generally heterogeneous. Southeasterly winds and the Northeasterly Mistral wind are important in the origins of circulated and mixed water masses. These winds are both frequent and strong. They have, as a result, a great effect on the water environment of Lake Etang de Berre. In theory, the annual precipitation in this region is well over eight times the water mass of the lake. The water of the Durance River flows into Lake Etang de Berre through the EDF Canal, amounting to 90% of the precipitation. However, reduction of rainfall in dry seasons has a serious effect on the hydrological characteristics of the lake. The temperature in the winter is partially caused by the low temperature of fresh water, particularly that of the Durance River. The hydrological season of fresh and brackish water is about one month ahead of the hydrological season of sea water in its vicinity. The salinity of Lake Etang de Berre runs approximately 3$\textperthousand$, except at lower levels and near the entrance to the Caronte Canal. However, when the volume of the Durance River water is reduced in the summer and fall, the salinity rises to 15$\textperthousand$. In the lake, the ratio of fresh water to sea water is six to one (6:1). The large quantities of seston conveyed by rivers, particularly the Durance diversion, strongly reduce the transparency in the brackish waters. Although the amount of sunshine is also notable, transparency is slight because of the large amount of seston, carried chiefly by Tripton in the fresh water of the Durance River. Therefore, photosynthesis generally occurs only in the surface layer. The transparency progressively increases from freshwater to open seawater, as mineral particles sink to the bottom (about 1.7kg $m^{-2}a^{-1}$ on the average in brackish lakes). The concentration of dissolved oxygen and the rate of oxygen saturation in seawater (Carry-le-Rouet) ranged from 5.0 to 6.0 $m\ell$ㆍ.$1^{-1}$, and from 95 to 105%, respectively. The amount of dissolved oxygen in Etang de Berre oscillated between 2.9 and 268.3%. The monographs of phosphate, nitrate, nitrite and silicate were published as a part of a study on the ecology of phytoplankton in these environments. Horizontal and vertical distributions of these nutriments were studied in detail. The recent diversion of the Durance River into Lake Etang de Berre has effected a fundamental change in this formerly marine environment, which has had a great impact in its plankton populations. A total of 182 taxa were identified, including 111 Bacillariophyceae, 44 Chlorophyceae, and 15 Cyanophyceae. The most abundant species are small freshwater algae, mainly Chlorophyceae. The average density is about $10^{8}$ cells $1^{-1}$ in Lake Etang de Berre, and about double that amount in Lake Etang de Vaine. Differences in phytoplankton abundance and composition at the various stations or at various depths are slight. Cell biovolume V (equivalent to true biomass), plasma volume VP (‘useful’ biomass) and, simultaneously. the cell surface area S and S/V ratio through the measurement of cell dimensions were computed as the parameters of phytoplankton productivity and metabolism. Pigment concentrations are generally very high on account of phytoplankton blooms by Cyanophyceae, Chlorophyceae and Cryptophyceae. On the other hand, in freshwaters and marine waters, pigment concentrations are comparatively low and stable, showing slight annual variation. The variations of ATP concentration were closely related to those of chlorophyll a and phytoplankton blooms only in marine waters. The carbon uptake rates ranged between 38 and 1091 mg$Cm^{-2}d^{-1}$, with an average surface value of 256 mg; water-column carbon-uptake rates ranged between 240 and 2310 mg$Cm^{-2}d^{-1}$, with an average of 810, representing 290 mg$Cm^{-2}$, per year 45 000 tons per year of photosynthetized carbon for the whole lake. Gross photosynthetic production measured by the method of Ryther was studied over a 2-year period. The values obtained from marine water(Carry-le-Rouet) ranged from 23 to 2 337 mg$Cm^{-2}d^{-1}$, with a weighted average of 319, representing about 110 gCm$^{-2}$ per year. The values in brakish water (Etang de Berre) ranged from 14 to 1778 mg$Cm^{-2}d^{-1}$, with a weighted average of 682, representing 250 mg$Cm^{-2}$ per year and 38 400 tons per year of photosynthesized carbon for the whole lake.

Photosynthetic Characteristics of Porphyra yezoensis Ueda Measured in situ by Diving Pulse-Amplitude Modulated (PAM) Fluorometry on the Southwestern Coast of the Korean Peninsula (남서해역에서 양식되는 방사무늬김(Porphyra yezoensis Ueda)의 Diving-PAM에 의한 광합성 특성)

  • Kim, Jeong Bae;Lee, Won-Chan;Kim, Hyung Chul;Choi, Hee-Gu;Park, Jung-Im;Cho, Yoonsik;Park, Hwan Hee
    • Korean Journal of Environmental Biology
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    • v.30 no.3
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    • pp.210-218
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    • 2012
  • The morphological characteristics, carbon and nitrogen concentrations, stable isotope values and photosynthetic rates of Porphyra yezoensis were studied at the main purple lavers production areas on southwestern coast of Korea. The morphological characteristics of leaf length, leaf width and weight of Porphyra blades were between 11.6~16.3 (average 13.8) cm, 4.6~6.3 (average 5.4) cm, $1.1{\sim}2.6(average\;1.86)g\;DW\;m^{-2}$, respectively. Photosynthetic pigment of Chl a concentration of Porphyra blades was between $2.18{\sim}17.77(average\;9.65)mg\;DW\;Chl\;a\;m^{-2}$. Carbon and nitrogen concentrations of Porphyra blades was between $201{\sim}317(average\;240)mg\;DW\;g^{-1}$, $39.8{\sim}50.0(average\;43.5)mg\;DW\;g^{-1}$ and C/N ratio 5.0~6.7 (average 5.5). The range of average ${\delta}^{13}C$ and ${\delta}^{15}N$ values of Porphyra blades was between - 25.6 to - 24.0 (average - 24.7)‰ for ${\delta}^{13}C$, and 1.3 to 4.1 (average 2.1)‰ for ${\delta}^{15}N$. Photosynthetic characteristics of seaweeds measured by pulse amplitude modulation (PAM) fluorometry was used as an indicator of photosynthetic activity. We use Diving-PAM fluorometry to examine photosynthetic rates of the seaweeds Porphyra yezoensis at each station. Maximum quantum yield of Porphyra blades was between 0.46~0.55 (average 0.52), the variance of the effective PS II maximum quantum yield of the station was broadly similar. Maximum relative electron transport rate (rETRmax) of Porphyra blades was between $4.71{\sim}5.84(average\;5.33){\mu}mol\;electrons\;m^{-2}\;s^{-1}$, the changes of maximum relative electron transport rate (rETRmax) of Porphyra yezoensis were similar to those of PS II maximum quantum yield. Photosynthetic efficiency (${\alpha}$) was between 0.027~0.045 (average 0.036). Minimum saturating irradiance ($E_k$) range was $139{\sim}180(average\;156){\mu}mol\;photons\;m^{-2}\;s^{-1}$. Minimum saturating irradiance ($E_k$) made a difference by station within the area on southwestern coast. Carbon and nitrogen concentrations and photosynthetic rates of Porphyra blades production areas on southwestern coast were broadly similar. The photosynthetic characteristics showed low photosynthetic rates because the low maximum quantum yields and low maximum relative electron transport rate.

Optimum Condition of Soil Dispersion for Remediating Heavy Metal-Contaminated Soils using Wet Magnetic Separation (중금속 오염 토양 정화를 위한 습식자력선별법 사용 시 최적 토양분산 조건)

  • Chon, Chul-Min;Park, Jeong-Sik;Park, Sook-Hyun;Kim, Jae-Gon;Nam, In-Hyun
    • Economic and Environmental Geology
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    • v.45 no.2
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    • pp.121-135
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    • 2012
  • Soil dispersion and heavy metal leaching with two heavy metal-contaminated soils were studied to derive the optimal dispersion condition in the course of developing the remedial technology using magnetic separation. The dispersion solutions of pyrophosphate, hexametaphosphate, orthophosphate and sodium dodecylsulfate (SDS) at 1 - 200 mM and the pH of solutions was adjusted to be 9 - 12 with NaOH. The clay content of suspension as an indicator of dispersion rate and the heavy metal concentration of the solution were tested at the different pHs and concentrations of the dispersion solution during the experiment. The dispersion rate increased with increasing the pH and dispersion agent concentration of the solution. The dispersion efficiency of the agents showed as follows: pyrophosphate > hexametaphosphate > SDS > orthophosphate. Arsenic leaching was sharply increased at 50 mM of phosphates and 100 mM of SDS. The adsorption of $OH^-$, phosphates and dodecysulfate on the surface of Fe- and Mn-oxides and soil organic matter and the broken edge of clay mineral might decrease the surface charge and might increase the repulsion force among soil particles. The competition between arsenic and $OH^-$, phosphates and dodecylsulfate for the adsorption site of soil particles might induce the arsenic leaching. The dispersion and heavy metal leaching data indicate that pH 11 and 10 mM pyrophosphate is the optimum dispersion solution for maximizing dispersion and minimizing heavy metal leaching.