• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.637-641
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• 2010

The antibiotics-resistance profiles of 28 strains of Vibrio parahaemolyticus isolated from seawater were investigated. All of the strains studied were resistant to ampicillin (100%), but susceptible to 12 other antibiotics. The minimum inhibitory concentration (MIC) of V. parahaemolyticus to ampicillin was as high as $1,024-2,048\;{\mu}g{\cdot}mL^{-1}$. The phenotype of strain 8 changed from ampicillin-resistant to susceptible with an in-frame deletion mutant of VPA0477, a putative ${\beta}$-lactamase gene, and the MIC for ampicillin of the mutant strain was $1{\mu}g{\cdot}mL^{-1}$. In conclusion, our findings suggest that the VPA0477 gene acts as a ${\beta}$-lactamase in ampicillin-resistant V. parahaemolyticus strains.

• Nuclear Engineering and Technology
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• v.14 no.3
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• pp.116-121
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• 1982

The uptake and retention of strontium-90 from seawater by the seaweed Undaria pinnatifda(sea mustard) varied depending on the plant part, exposure time, salinity, contents of stable strontium and calcium, and presence of chelating agent in the seawater. The concentration factors attained at equilibrium were in the range of 50 and it was evident that the bioaccumulation was largely due to the adsorption of the radionuclide on the surface of seaweed.

• Journal of Environmental Science International
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• v.9 no.4
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• pp.285-294
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• 2000

Butyltin compounds (BTs) in seawater, sediments and organisms (Thais clavigera, Liolophura japonica and Cellana nigrolineata), were quantitatively determined to evaluate their distribution inside Songsan Harbor of Cheju Island. In addition, imposex in T. clavigera was used to assess the effect on organisms of BTs. Analysis of the samples collected in seawater, sediments (March, June and August) and organisms (May, July and August) in 1998, confirmed the contamination of BTs in the aquatic environment inside Songsan Harbor. The main BTs species in seawater and sediments was monobutyltin (MBT), tributyltin (TBT), respectively, irrespective of survey time. In oranisms, TBT and dibutyltin (DBT) were detected in similar concentrations for T. clavigera and L. japonica, but for C nigrolineata, DBt concentration was the highest. TBT, the most toxic to aquatic organisms among BTs, was found at concentrations which were sufficient to have a serious effect on the sensitive organisms upon chronic exposure, The relatively high correlations (r>0.83) between BTs indicated that DBT and MBT were mainly degraded from TBT based on antifouling paint and their sources were negligible. The sedimentary organic matters did not have influence on the distribution of BTs in marine environment, and lipid content in T. clavigera did not show a correlation with TBT concentrations. The rate of occurrence of imposex in T. clavigera was 100%, and the relative penis length index (RPLI) and the relative penis size index (RPSI) which represent the degree of imposex were 79.7%, 58.1%, respectively. Measurement of imposex in T. clavigera was expected to be a very helpful tool for preliminary survey of BTs prior to trace analysis of BTs.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.2
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• pp.152-159
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• 2017

In marine environment, the durability of concrete and reinforcing steel is known to be deteriorate by the permeation of chloride ion into concrete. In this study the conductive photocatalyst was used to improve the seawater corrosion resistance of the concrete and steel. Mortar and concrete samples were prepared by mixing with various amounts of conductive active carbon and photocatalytic powder($TiO_2$). The compressive strength of concrete was decreased with the increase of the amount of conductive carbon powders. The samples containing conductive carbon and photocatalytic powders showed the superior seawater corrosion resistance compared with the ordinary sample, which was verified by XRF analysis showing the concentration of chloride ion($Cl^-$) of mortars and concretes. The inhibitive effect of photocatalyst against chloride attack was discussed with the diffusion coefficient of chloride ion into mortar and concrete.

• Journal of Environmental Health Sciences
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• v.44 no.2
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• pp.133-142
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• 2018

Objectives: The pathogenic Vibrios genus denotes halophilic bacteria that are distributed in aquatic environments, including both sea and freshwater. Vibrio cholerae, Vibrio vulnificus, and Vibrio parahaemolyticus are the most important species since they can be potent human pathogens and leading causes of septicemia, wound infections, and seafood borne gastroenteritis. The recent emergence of a potential pandemic clone, V. cholera serotype O1 and the cholera outbreak in South Korea in 2016 indicates the importance of consistent surveillance of pathogenic Vibrio genus within coastal areas. Methods: The present study was undertaken to determine where and how vibrios live in the aquatic environment adjacent to coastal areas of South Korea. For this survey, a total of 838 samples were obtained at 35 different sites in South Korean coastal areas during the period from January 2016 to December 2016. Pathogenic vibrios was determined using the real-time PCR method, and its clones were isolated using three selective plating media. We also monitored changes in seawater and atmospheric temperature, salinity, turbidity, and hydrogen ion concentration at the collection points. Results: The total isolation rates of V. vulnificus, V. cholera (non-pathogenic, non-O1, non-O139 serogroups), and V. parahaemolyticus from seawater specimens in 2016 were 14.2, 13.48, and 67.06%, respectively. Conclusions: The isolation rates of pathogenic vibrios genus showed a positive correlation with temperature of seawater and atmosphere but were negatively correlated with salinity and turbidity.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.5
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• pp.17-23
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• 2013

Six-valent chromium ($Cr^{6+}$) is a highly toxic pollutant, supplied in a variety of industrial activities such as leather tanning, cooling tower blowdown, and plating. Herein, we investigated the removal of $Cr^{6+}$ from aqueous phase using low-cost adsorbents. Steel slag, montmorillonite, illite, kaolinite, red mud, and acid treated red mud with 0.5, 1.0, and 2.0 M HCl were used as adsorbent for the removal of $Cr^{6+}$ and the results showed that acid treated red mud with 2.0 M HCl (ATRM-2.0 M) had higher adsorption capacity of $Cr^{6+}$ than other adsorbents used. Accordingly, $Cr^{6+}$ removal by ATRM-2.0 M were studied in a batch system with respect to changes in initial concentration of $Cr^{6+}$, initial solution pH, adsorbent dose, adsorbent mixture, and seawater. Equilibrium sorption data were described well by Freundlich isotherm model. The influence of initial solution pH on $Cr^{6+}$ adsorption was insignificant. The use of the ATRM-2.0 M alone was more effective than mixing it with other adsorbents including red mud, zeolite, oyster shell, lime stone, and montmorillonite for the removal of $Cr^{6+}$. The $Cr^{6+}$ removal of the ATRM-2.0 M was slightly less in seawater than deionized water, resulting from the presence of anions in seawater competing for the favorable adsorption site on the surface of ATRM-2.0 M. It was concluded that the ATRM-2.0 M can be used as a potential adsorbent for the removal of $Cr^{6+}$ from the aqueous solutions.

• Journal of Environmental Science International
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• v.11 no.8
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• pp.793-800
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• 2002

Butyltin (BT) compounds were measured in seawater, sediment, sediment core, settling solids, and plankton from Gwangyang Bay in 2001, Tributyltin (TBT) was detected in seawater from 1 out of the 7 seawater sampling sites and in sediment from 18 out of the 35 sediment sampling sites. The highest concentration of TBT was found in the sediment from the site near Yeosu Harbor (53 ng Sn/g dry wt), acting as the point source for TBT The mean concentrations of TBT were in the order of plankton> settling solids> sediment. The degradation indexes ([DBT]+[MBT]/[TBT]) for the plankton were less than 1, indicating the possibility of recent inputs of TBT. The indexes for the sediment and settling solids ranged from 1.14 to 8.73. The composition of the BT compounds found in the settling solids was similar to that found in the sediment. The vertical profile of the total BT compounds in the sediment was characterized by an abrupt decline from the surface. However, no butyltin compounds appeared below a depth of 10 cm, corresponding to the 1980s. Accordingly, the current results demonstrated that the levels of all butyltin species in the environment of Gwangyang Bay were relatively lower than those in other polluted coastal areas. The vertical profile also suggested a fairly recent history for the down-core.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.1-6
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• 2016

Seawater desalination plants generally have two inherent problems which stem from energy inefficiency and desalination concentrate management. The former has been somewhat resolved thanks to the innovative methods in utilizing new and renewable energy resources whereas the latter still has much issues to be dealt with. This paper introduces the application of a desalting process for the disposal of desalination concentrate (especially, Mg) and to improve its cost effectiveness of a MVR seawater desalination plant built in Jeju. Principal component analysis on the desalination concentrate has revealed a steady reduction of Mg with the application of the desalting process verifying its functional reliability. Also, it was found that our MVR seawater desalination plant is not only energy efficient but also could be effectively applied for the dual purpose of fresh water production and concentrate management.

• Journal of Environmental Science International
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• v.9 no.1
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• pp.1-11
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• 2000

A study on the variational characteristics of water quality and phytoplankton biomass by principal component analysis(PCA) was carried out in Kogum-sudo from February to October in 1993. We analyzed PCA on biological factors such as chlorophyll a and phytoplankton cell numbers for centric and pennate diatoms, phytoflagellates, and total phytoplankton as well as physico-chemical factors as water temperature, salinity, transparency, dissolved oxygen(DO), saturation of DO, apparent oxygen utilization (AOU), chemical oxygen demand(COD), nutrient (ammonia, nitrite, nitrate, phosphate and silicate), N/P ratio and suspended solid(SS). The source of nutrients supply depended on the mineralization of organic matters and inputs of seawater from outside rather than runoff of freshwater. The phytoplankton biomass was changed within short interval period by nutrients change. And it was controlled by the combination of several environmental factors, especially of light intensity, ammonia and phosphate. The marine environmental characteristics were determined by the mineralization of organic matters in winter, by runoff of freshwater including high nutrients concentration in spring, by ammonia uptake and high phytoplankton productivity in summer, and phosphate supplied input seawater from outside of Kogeum-sudo in autumn. And Kogum-sudo was separated with 2 regions by score distributions of PCA. That is to say, one region was middle parts of straits which was characterized by the mixing seawater and the accumulated organic matters, other one region was Pungnam Bay and the water around Kogum Island which was done by high phytoplankyon biomass and productivity year-round.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.343-351
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• 2017

Sanitary evaluation of seawater and Pyropia sp. laver collected from the five major laver growing areas in Korea was performed four times over the course of a year. The seawater quality in four of these five areas was regarded as the clean area according to Korean criteria, but the seawater at one investigation site in Seoheon area was found to exceed the standard for fecal coliform. In the bacteriological safety analysis of laver (raw source), the percentages of samples not conforming to Chinese criteria at the five sites were 55.6% (Seocheon), 70.0% (Shinan), 81.8% [Jindo (Haenam)], 63.6% (Wando), and 28.6% [Goheung (Jangheung)]. Pathogenic bacteria were not detected in all laver samples. The food safety of laver (raw source) based on heavy metal concentration was confirmed using Korean criteria; the concentrations of heavy metals in laver samples collected from the major laver growing areas were 0.008-0.632 mg/kg wet weight (ww) lead, 0.024-0.137 mg/kg ww cadmium, 0.908-2.892 mg/kg ww total arsenic, and 0.003-0.013 mg/kg ww total mercury. Therefore, pollution source management and periodic monitoring of heavy metals may be required to improve the food safety of laver produced in these laver growing areas.