• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.605-616
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• 2019

This study evaluated the abundance and antimicrobial resistance of Escherichia coli in oysters Crassostrea gigas and major inland pollution sources sampled in 2014-2015 from Jaranman-Saryangdo on the southern coast of Korea. The ranges of the geometric mean of E. coli concentrations in oysters and major inland pollution sources were <20-29.8 MPN/100 g and 7.5-137.2 MPN/100 g, respectively. We isolated 247 strains of E. coli (28 from oysters and 247 from major inland pollution sources) and examined the antimicrobial resistance patterns of all isolates. Isolates from both sources were highly resistant to rifampin (99.5-100%) and cephalothin (70.8-78.6%). The resistance rate was higher in E. coli isolated from oysters those from inland pollution sources. Multiple resistance against at least four antimicrobials was observed in 85.7% and 21.0% of the oyster and major inland pollution sources isolates, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.612-621
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• 2011

The influences of inland pollution sources because of rainfall events on the bacteriological water quality in Geoje Bay, a major shellfish production area in Korea, were investigated. The sanitary status of sea water and shellfish after rainfall events was also evaluated. The flow rates of 13 streams around Geoje Bay showed 6 to 7-fold increases after 15 to 21 mm of rainfall. Peak pollution was observed in the Naegan Stream, the Gandeok Stream and the Seojeong Stream. The calculated impact area of inland pollution sources was 3.1 $km^2$ immediately after 15 mm of rainfall and expanded to 3.5 $km^2$ after 24 hours. These calculations of impacted area matched results from fecal coliform analyses with sea water. The distance between the major pollution source in the bay (the Gandeok Stream) and the station with the worst bacteriological water quality immediately after 15 mm of rainfall, which was below the Korean standard, was 0.8 km in a straight line; this distance increased to 2.0 km after a period of 24 hours. The area impacted by inland pollution sources after a 15 mm rainfall event was wider than after a 21 mm rainfall. Although the flow rate from inland pollution sources was higher, the concentration of fecal coliform in the discharged water was lower after higher rainfall events. These observations corresponded with the results of fecal coliform analyses with sea water samples. According to the evaluation of the influences of inland pollution sources and fecal coliform analyses on sea water and shellfish samples in Geoje Bay, pollutants from inland sources did not reach the boundary line of the shellfish growing area after rainfall events of 15 or 22 mm. The bacteriological water quality of the shellfish growing area in Geoje Bay met the Korean standard and US NSSP requirements for approved shellfish growing areas.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.6
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• pp.673-681
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• 2018

We isolated and characterized Escherichia coli (E. coli) from oyster Crassostrea gigas and inland pollution sources on Yongnam-Gwangdo island and neighboring areas on the southern coast of Korea in 2014-2015. A total of 222 strains of E. coli were isolated from 132 oysters and 88 samples from inland pollution sources. These 222 isolates were tested for their susceptibility to 24 antimicrobial agents, and 221 isolates were found resistant to the tested antibiotics. Of these 99.5% and 70.7% of the isolates showed very high resistance to rifampin and cephalothin respectively, followed by tobramycin (23.4%), streptomycin (20.2%), tetracycline (19.4%), cefepime (18.9%), ceftazidime (18.9%) and nalidixic acid (16.7%). The resistance rate of E. coli isolated from oysters was higher than that from inland pollution sources. In addition, multiple resistance to at least four antibiotics were present in 73.2% and 26.5% of E. coli isolates from oysters and inland pollution source samples, respectively.

• Journal of Environmental Science International
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• v.31 no.6
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• pp.491-501
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• 2022

This study evaluated the contamination levels of inland pollution sources flowing into Taeanhaean National Park. The nutritional status of influents was assessed by analyzing water quality and trophic status index (TRIX) at 52 stations, and the contamination levels of sediments were evaluated by analyzing eutrophication cleanup index (CIET) and heavy metals at 36 stations. The results of the TRIX analysis showed that 26 of the 52 stations had influents with a TRIX value of 6-10 (poor water quality/very high trophic level), indicating atrocious water quality and high eutrophication levels. The results of the CIET analysis showed that 4 out of the 36 stations were highly contaminated with organic matter. Analysis of heavy metals showed that the copper (Cu) and zinc (Zn) levels exceeded the threshold effects level (TEL) and probable effects levels (PEL) at several stations. In addition, the arsenic (As) level exceeded the threshold effects level at one station, and the levels of the other heavy metals (Cd, Cr⁶⁺, Ni, Pb, and Hg) were lower. Most inland pollution sources have been identified as small-scale, but long-term and continuous exposure can negatively affect the marine ecosystem; therefore, it necessary to prepare inland pollution source management standards and measures suitable for the characteristics of the coastal area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.564-572
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• 2016

In this study, we isolated and characterized Escherichia coli from mussels and inland pollution sources in or in proximity to the Changseon area on the southern coast of Korea in 2014. A total of 147 strains of E. coli were isolated from 54 mussels and 32 pollution-source samples. The susceptibility of the isolates to 24 antimicrobial agents was analyzed. The resistance of E. coli isolates to rifampin was highest at 100%, followed by cephalothin (98.6%), tetracycline (91.8%), amikacin (81.0%), ampicillin (79.6%), cefazolin (79.6%), streptomycin (73.5%), piperacillin (70.7%), gentamicin (37.4%), cefoxitin (35.4%), cefamandole (34.7%), tobramycin (29.9%), amoxicillin/clavulanic acid (24.5%), nalidixic acid (21.8%), trimethoprim (19.0%), chloramphenicol (17.7%), cefotaxime (12.9%), trimethoprim (10.9%), ceftazidime (10.2%), aztreonam (7.5%), imipenem (2.7%), cefepime (2.0%), and cefotetan (0.0%). In addition, the antimicrobial resistance of E. coli isolates from inland pollution sources was slightly greater than or similar to that of isolates from mussels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.377-387
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• 2021

Fecal contamination levels of discharge water from inland pollution sources were investigated in Iwon-myeon (Taean-gun), South Korea. Gram-negative bacteria were isolated during the investigation and the antimicrobial resistance patterns of the isolates were examined to estimate their impact on the coastal environment. The ranges of total coliform and fecal coliform of 12 samples from four major inland pollution sources were 79-490,000 MPN/100 mL and 2.0-490,000 MPN/100 mL, respectively, with the highest level of fecal contamination at Station No. 3. A total of 137 strains (14 genus) were isolated, of which 86 strains (62.8%) were Enterobacteriaceae. The identified isolates were as follows: Pseudomonas spp. (35 strains), Klebsiella spp. (20 strains), Serratia spp. (20 strains), and Escherichia spp. (19 strains). The isolated Gram-negative bacteria showed the highest antimicrobial resistance to ampicillin (81.8%), followed by amoxicillin/clavulanic acid (64.2%), ceftiofur (61.3%), and cefoxitin (59.1%). Antimicrobials in which less than 10% of isolates showed antimicrobial resistance were ciprofloxacin (3.6%) and gentamicin (2.2%). Resistance to one or more antimicrobials was observed in 121 strains (88.3%) and 84 strains (61.3%) showed a tendency for multiple antimicrobial resistance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.160-167
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• 2013

The influences of inland pollution sources nearJeokyang and Jangpoports following rainfall events on the bacteriological water quality and safety of commercial shellfish were investigated in the Changseon area, Korea. Stream flow rates exhibited 1.9- to 5.7-fold increases after rainfall events and then fell to 68~81% of that level after 24 h. The calculated impact area of inland pollution sources was 0.47 $km^2$ in the Jeokyangport area and 0.27 $km^2$ in the Jangpoport area at 24 h following 11 mm of rainfall. When the flow rate of inland pollution increased, the level of male-specific bacteriophage (MSB) decreased, and no MSB could be detected in seawater samples, whereas 30 PFU/100 g was detected in shellfish samples. Fecal coliform levels in seawater and shellfish samples did not exceed their respective tolerance levels (4.5 MPN/100 mL) and 130 MPN/100 g, respectively and thus complied with the standard for approved shellfish growing area. The sanitary conditions of areas adjacent to Jeokyang and Jangpoports under conditions of rainfall below 29 mm met the criteria for approved growing area under the United States National Shellfish Sanitation Program and the EC Regulations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.1-7
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• 2018

We investigated patterns of antimicrobial resistance in Escherichia coli isolated from the water discharged from inland pollution sources in the Hansan-Geojeman and Jaranman-Saryangdo areas of Korea. A total of 217 strains of E. coli were isolated from 23 point-sources. These strains were tested for their susceptibility to 16 antimicrobial agents used in Korea for medical or veterinary therapy. The highest level of antibiotic resistance among the isolated strains was to tetracycline 10.6%, followed by ampicillin (3.2%), nalidixic acid (2.8%), rifampin (1.8%), trimethoprim (1.8%), trimethoprim/sulfamethoxazole (1.8%), chloramphenicol (1.4%), streptomycin (1.4%), cephalothin (0.5%) and gentamicin (0.5%). Resistance to at least one antimicrobial agent was present in 17.1% of the E. coli isolates. Only four of the isolated strains of E. coli showed multiple antibiotic resistance, which is defined as resistance to more than four antibiotics.

• Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.17.1-17.9
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• 2016

The seasonal variation of fecal coliforms (FCs) and physicochemical factors was determined in seawaters of the Hansan-Geojeman area, including a designated area for oyster, and in inland pollution sources of its drainage basin. The mean daily loads of FCs in inland pollution sources ranged from $1.2{\times}10^9$ to $3.1{\times}10^{11}$ most probable number (MPN)/day; however, the pollutants could not be reached at the designated area. FC concentrations of seawaters were closely related to season, rainfall, and inland contaminants, however, within the regulation limit of various countries for shellfish. The highest concentrations for chemical oxygen demand (COD) and $chlorophyll-{\alpha}$ in seawaters were shown in the surface layer during August with high rainfall, whereas the lowest for dissolved oxygen (DO) in the bottom layer of the same month. Therefore, it indicates that the concentrations of FC, COD, DO, and $chlorophyll-{\alpha}$ of seawaters were closely related to season and rainfall.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.798-809
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• 2023

In this study, we evaluated the impacts of land-based pollution sources on seawater and shellfish in the Jindongman area after 20.5 mm and 90.6 mm rainfall events. We analyzed sanitary indicator microorganisms used in survey management, such as total coliform, fecal coliform, Escherichia coli, and male-specific coliphage in Waste water treatment plant (WWTP), major inland pollution source,s seawater, and shellfish for 4 days after rainfall events. Our results showed that the range of coliform group and fecal coliform was 1.8-49 and <1.8-4.5 MPN (most probable number)/100 mL, respectively, after rainfall events in WWTP discharge water. Furthermore, the radius of the calculated impacted area of major inland pollution sources ranged from 5 to 798 m after 20.5 mm of rainfall and 30 to 1,031 m after 90.6 mm of rainfall. The fecal coliform of seawater at 30 stations in the shellfish growing area and areas adjacent to four stations was <1.8-130 and from <1.8-79 MPN/100 mL, respectively. The E. coli level of shellfish at 7 stations in the shellfish growing area was <18-220 MPN/100 g.