Chul-Hwan Koh

Seoul National University, Sŏul, Seoul, South Korea

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Publications (17)28.93 Total impact

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    Chul-Hwan Koh, Jong Seong Khim
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    Chul-Hwan Koh, Jong Seong Khim
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    ABSTRACT: The present article provides a regional overview of the Korean tidal flat extensively developed along the West Sea of Korea, encompassing oceanographic features, geology, and biology. In particular, the Korean tidal flat was fully described in the aspects of spatial scale (viz. size), geographical distribution, biodiversity, and local culture. A particular emphasis was given to explain the framework of the coastal management in Korea, in terms of a legal aspect, by highlighting reclamation versus protection issues. First, we described the Yellow Sea by sketching the boundary, ocean and tidal currents, discharges from the major rivers, sedimentology, and the cooperative surveys between Korea and China. Next, the West Sea of Korea, where the offshore boundary often neighbored rather close to coastal zone because of the associating traditional livelihoods, was described to point out certain characteristics of hydrography, coastal landscape, tidal channels, tide, and sedimentary process. Then the Korean tidal flat which is the main topic of this article was introduced by highlighting the geographical distribution, biodiversity of benthic diatoms and macrozoobenthos, artisanal fisheries, and local culture in aspect of ecosystem services in tidal flats. Meantime, the issue of reclamation was mini-reviewed by tracking the chronicle development, aerial coverage, and deteriorated environmental impacts on the coastal ecosystem. Herein, the untiring efforts towards protection of the Korean tidal flat are also included in viewpoints of legal framework and the designation of protected areas. Overall, the present collective description aims an introductory guidance for the individual papers of the special issue on the Korean tidal flat, with provisioning several key maps to be cross-utilized or referred.
    Ocean & Coastal Management 01/2014; · 1.60 Impact Factor
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    Jinsoon Park, Taisuke Ohtsuka, Chul-Hwan Koh
    10/2013;
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    ABSTRACT: A taxonomic investigation of the microphytobenthos from the lower intertidal zone of a Korean sandflat revealed unprecedented dominance and diversity of the marine diatom genus Fogedia. Four new species are described: Fogedia coreana sp. nov., F. densa sp. nov., F. elliptica sp. nov., and F. lyra sp. nov. A great abundance of Fogedia species in the study area provided a unique opportunity to observe the frustule ultrastructure and cell contents. The first reported observation of the presence of two girdle-appressed plastids each with a single rod-like pyrenoid was made in species of Fogedia, indicating its close relationship to Navicula sensu stricto and Hippodonta. Ultrastructural characteristics (e.g. hymenate areola occlusions) of Fogedia also support such a relationship. Meanwhile the genus Fogedia differs from Navicula sensu stricto with respect to the raphe system and differs from Hippodonta with respect to the girdle bands and apical striae. The present study increased the overall worldwide number of the taxa of Fogedia to 13. An emended generic description of Fogedia is provided along with the biogeographic information of the species belonging to the genus.
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    ABSTRACT: The effect of sediment pollution on benthos was investigated in the vicinity of a large sewage treatment outflow at Incheon North Harbor, Korea. Animal size, vertical distribution and standard community parameters were analyzed along a 3 km transect line (n = 7). Univariate parameters showed a general trend of increasing species diversity with increasing distance from the pollution source. Multi-dimensional scaling analysis led to the clear separation of 3 locational groups, supporting gradient-dependent faunal composition. The innermost location was dominated by small sub-surface dwellers while the outer locations by large mid to deep burrowers. Looking for the size-frequency distribution, most abundance species (Heteromastus filiformis) showed the presence of larger size animals with increasing proximity to the pollution source. Meanwhile, species-specific vertical distributions, regardless of the pollution gradient, indicated that such shifts were due to species replacement resulting from a higher tolerance to pollutants over some species.
    Environmental Pollution 06/2011; 159(10):2622-9. · 3.73 Impact Factor
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    ABSTRACT: This study aims to contribute to the development of heuristic statistical models, which are able to predict benthic macrofaunal responses to environmental gradients in coastal areas, such as tidal flats. Ecological response surfaces were derived for 15 intertidal macrobenthic species, using logistic regression based on three separate environmental parameters (shore level, mud content, and organic content) measured on the tidal flats of the Saemangeum estuary, Korea. The presence/absence of the 15 intertidal macrofauna was accurately predicted from each separate environmental factor in the environmental models, with a prediction accuracy of ~65–92%. Subsequently, geographical comparison was made between the mapped probability surfaces and maps of observed species occurrence. The results indicated that the models developed for different species exhibited a wide variety of functional forms, highlighting potential variability in species response to changes in habitat conditions, even for closely associated species with a similar trophic type. Our modeling approach was capable of predicting macrobenthic species distributions with a relatively high degree of accuracy, although the ecological processes controlling intertidal macrobenthic distribution could not be fully determined. Overall, good agreement between modeling results and field observations, with relatively high concordance regardless of target species, emphasized that such an approach would be of practical use in terms of ecosystem approach to tidal flat management. KeywordsLogistic regression–Statistical modeling–Benthic macrofauna–Saemangeum–Tidal flat
    Ecological Research 01/2011; 26(3):659-668. · 1.55 Impact Factor
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    Jong Seong Khim, Chul-Hwan Koh
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    ABSTRACT: Here we present our triad approach followed by major findings based on sediment pollution studies that determined the chemical concentration, biological effect, and community structure associated with trace pollutants in the Korean coastal environment. Since the late-1990s, over several hundred sites along the Korean coast have been surveyed including sediment (including pore-water), water, and biological samples and analyzed for instrumental quantification, in vitro and in vivo bioassays, and benthic community indices. The instrumental data of persistent heavy metals and organic pollutants in Korean sediments generally suggest that concentrations of target pollutants are relatively low to moderate but their distribution is widespread across the coasts. The compositional pattern and spatial distribution suggests that their sources are independent of each other. However, there are local zones with extremely high concentrations of certain pollutants indicating point sources. In order to search for the relationship between chemical concentrations and biological responses, some selected data (n=123) were further analyzed in terms of mass balance analysis (sediment-TIE towards TEQ approach). Most of the dioxin-like activities were observed in the fractions containing dioxins, furans, and certain polycyclic aromatic hydrocarbons (PAHs) and about half of the samples showed significant estrogenic activities in the fractions of PAHs and alkylphenols. Direct relationship(s) between chemical and ecotoxicological data could not be fully addressed between component(s). However, a positive relationship between them became apparent in some cases, indicating a general good agreement between chemical stresses and biological responses. Overall, we found that a sediment triad approach for an integrated assessment of trace pollutants in the coastal environment was extremely useful. It would be much more powerful when all the components are fully and simultaneously analyzed and interpreted. KeywordsSediment quality triad–Trace pollutants–Bioassay–Community level response–Coastal environment
    01/2011; 3(2):59-68.
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    ABSTRACT: Estuarine tidal flats are both ecologically and economically important, hence developing methods to reliably measure ecosystem health is essential. Because benthic fauna play a central role in the food web of tidal flats, in this study we set out to quantitatively describe the intertidal zonation of macro-invertebrates and their associations with specific environmental parameters along three transects in the Saemangeum tidal flat, Korea. The abundance and biomass of intertidal fauna with respect to five environmental parameters (i.e., shore level, mud content, coarse sand content, water content, and organic content) were measured, to identify environmental factors that influence macrofaunal distribution in intertidal soft bottom habitats. A total of 75 species were identified, with dominant species showing distinct zones of distribution along all transects. The number of species recorded in each transect was found to be dependent on sediment characteristics and salinity. Cluster analysis classified the entire study area into three faunal assemblages (i.e., location groups), which were delineated by characteristic species, including (A) ‘Periserrula–Macrophthalmus’, (B) ‘Umbonium–Meretrix’, and (C) ‘Prionospio–Potamocorbula’. Four environmental variables (i.e., shore level, water content, mud content, and organic content) appeared to determine factors that distinguished the three faunal assemblages, based on the discriminant analysis. The faunal assemblage types of the sampled locations were accurately predicted from environmental variables in two discriminant functions, with a prediction accuracy of 98%. It should be noted that the zonation of benthos in the lower section (C) of Sandong had been affected by the construction of a nearby dike, while this parameter had remained essentially unchanged at the other two location groups (A–B). Overall, the zonation of benthos from the Saemangeum tidal flat was explained adequately by the measured environmental variables, implying that faunal assemblages are closely associated with certain combinations of abiotic factors. The identification of such reliable associations may facilitate the development of statistical models to predict faunal distributions based on environmental variables at both local and regional scales. The entire study area was embanked in 2006 (one year after this study), and an integrated plan was set into force to develop claimed land into industrial, residential and agricultural districts, which also included a partial restoration program of the tidal flats located near to the study area.Graphical abstractResearch highlights► High linkage of sediment properties and salinity to species composition/distribution. ► Identification of 3 faunal assemblages along the transect indicating clear zonation. ► Prediction of faunal assemblage type using two discriminant functions. ► A long-term benthic community change reflecting impact from dike construction.
    Journal of Sea Research 01/2011; 65(4):390-400. · 1.83 Impact Factor
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    ABSTRACT: The history of Korean tidal flat management and the process for designating Coastal Wetland Protected Areas (CWPAs) are described. Korean coastal wetlands have a long history of intensive use through reclamation for agricultural and industrial uses in the 20th century. Recently, the management policy is shifting away from intensive use towards the conservation of wetlands. This shift is caused by increasing public awareness of the value of wetlands and strong institutional support from the government. Since the Wetlands Conservation Act was passed in 1999, a total of twelve CWPAs have been designated through both top-down and bottom-up processes. Three designation paths are classified based on the relevant drivers, namely government-driven designations (seven CWPAs), local community driven designations (three CWPAs), and conflict resolution (trade-offs) driven designation (two CWPAs). The lessons learned from the designation of Korean CWPAs is that diversification of designation process could facilitate voluntary participation of local stakeholders and thereby enhance the chance of successful implementation of wise use strategy of tidal flats.Research highlights►Korean wetland management policy shift in the mid of 1990s. ►Twelve Coastal Wetland Protected Areas have been designated. ►Three designation paths are observed in Korean wetland management. ►Diversification of designation process could enhance MPA success.
    Ocean & Coastal Management 11/2010; 53(11):703-710. · 1.60 Impact Factor
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    ABSTRACT: Soil, sediment, water, and biota collected from the western coast of Korea were analyzed to determine occurrence and sources of perfluorinated compounds (PFCs). PFCs were significantly concentrations of PFCs were measured in some water and biological samples, while concentrations of PFCs in soils and sediments were relatively low. The most widely detected compound was found to be perfluorooctanesulfonate (PFOS), with a maximum concentration in water of 450 ng/L and in fish of 612 ng/g, dw. PFOS concentrations in water and biota were both less than those thought to cause toxicity. However, in both cases concentrations were within a factor of 10 of the toxicity threshold concentration. Concentrations of PFCs were significantly greater downstream than those upstream on the same river, suggesting point sources. Overall, the detection of PFCs at relatively great concentrations in various environmental matrixes from this region of Korea suggests that further studies characterizing PFCs and their potential risk to both humans and wildlife are needed.
    Environmental Pollution 02/2010; 158(5):1237-44. · 3.73 Impact Factor
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    ABSTRACT: The paper describes the history and the evolution of the conflict of the Saemangeum reclamation project, focusing on the court trial processes. The Saemangeum project is the world largest coastal reclamation work, regarded as the most controversial environmental issue in the recent history of Korea. Due to the severe pollution found in Lake Sihwa in 1996, the Saemangeum project began to receive a large degree of public concern on the water quality of the proposed artificial freshwater lake. Unlike the Sihwa case, the Korean court system intervened to resolve the heated conflicts between stakeholders in the Saemangeum case. Based on the same set of facts, the Korean courts showed different perspectives on the economic feasibility, value of the ecosystem, land use, and water quality, which represents the limit of legal system to address complicated environmental problems. After the final judgment by the Supreme Court, 'the Special Act for the promotion of the Saemangeum reclamation project', was enacted with strong political support from local leaders and congressmen. A more developmental-oriented land use plan came out in 2009 based on this Act. The Saemangeum project walked along the different pathway from the Sihwa case. The area should be managed in sustainable manners to appropriately consider conservation and development for the prosperity of local residents and future generations.
    Journal of the Korean Society for Marine Environment & Energy. 01/2010; 13(4).
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    ABSTRACT: Lake Shihwa is an artificial lake, located on the west coast of Korea, that has experienced environmental deterioration since 1994, when it was formed by construction of a sea dike. This study used instrumental analysis and in vitro bioassays to characterize organic contaminants in sediment collected from 11 stations on Lake Shihwa. Alkylphenol (AP) concentrations in Lake Shihwa sediment ranged from 20.2 to 1,820 ng/g nonylphenol and from 4.69 to 50.5 ng/g octylphenol, on a dry weight basis. Maximum concentrations of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, and polychlorinated biphenyls (PCBs) were 30.8, 2.26, and 12.3 ng/g (dry weight), respectively. Significant estrogenic activity was associated with fractions containing APs. Mass-balance analysis suggested that reported concentrations of APs account for less than 20% of the estrogenic activity observed. No significant dioxinlike activity was associated with fractions containing classic aryl hydrocarbon receptor agonists, such as PCBs, but the mid-polarity fractions containing PAHs and most polar fractions yielded significant dioxinlike activity. Overall, most of the in vitro bioassay responses appear to have been caused by unidentified and/or undetectable compounds associated with Lake Shihwa sediment.
    Environmental Toxicology and Chemistry 11/2009; 18(11):2424 - 2432. · 2.62 Impact Factor
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    ABSTRACT: This study employed mechanism-specific in vitro bioassays to help characterize the occurrence and distribution of dioxin-like and estrogenic contaminants in sediment from Yeongil Bay, Korea. Approximately 85% of the sediments tested induced significant dioxin-like activity in the H4IIE-luc bioassay, while approximately 50% induced significant estrogenic activity in the MVLN bioassay. Instrumentally-derived estimates of 2,3,7,8-tetrachlorodibenzo-p-dioxin and 17beta-estradiol equivalents tended to underestimate the magnitude of response observed in the bioassays, suggesting that compounds detected by chemical analysis did not account for all the activity associated with Yeongil Bay sediments, or that non-additive interactions were occurring. The greatest dioxin-like and estrogenic activity was associated with the mid-polarity Florisil fractions (F2) expected to contain polycyclic aromatic hydrocarbons (PAHs) as well as chlorinated dioxins and furans. As in previous studies of Korean coastal sediment, more polar fractions (F3) generated more modest responses both in terms of magnitude and the number of samples responding.
    Environmental Pollution 08/2006; 142(1):48-57. · 3.73 Impact Factor
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    ABSTRACT: Concentrations of polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides (HCB, HCHs, CHLs, and DDTs), polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), and bisphenol A (BPA) were measured in 26 marine sediments collected from Yeongil Bay, Korea, in order to characterize their spatial distribution and sources. PCBs (2.85-26.5 ng/g, dry wt.) were detected mainly in the inner bay locations Mean OC pesticide ranged from 1.16 ng/g dry wt. for HCH to 0.05 ng/g dry wt. for HCB). PAH concentrations ranged from <10.0 to 1870 (mean: 309)ng/g dry wt., and were predominated 3- and 4-ring congeners. Concentrations of APs, such as nonylphenol, octylphenol, butylphenol (means 89.1, 4.61, 11.0 ng/g dry wt., respectively), were greater at locations proximal to municipal wastewater discharges. Concentrations of PCBs and PAHs were great near shipyards and industrial complexes. Vertical profiles of PAHs and APs indicated that they have been associated with sediments since the 1950s.
    Environmental Pollution 08/2006; 142(1):39-47. · 3.73 Impact Factor
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    ABSTRACT: Sediments from inland areas and open bays along the Korean coast were analyzed to examine the distribution of dioxin-like and estrogenic compounds. Concentrations of target chemicals varied considerably among locations (Lake Shihwa, Masan Bay, and Kwangyang Bay) and between inland and coastal areas. Principal component analysis (PCA) of contaminants measured in sediments showed that all of the inland locations from Lake Shihwa were highly contaminated, and the variations among locations were explained predominantly by the distribution of alkylphenols and polycyclic aromatic hydrocarbons (PAHs). PCA of PAH congener profiles among locations indicated that automobiles were a major source of PAH contamination. Dioxin-like and estrogenic activities associated with sediment from inland sites were approximately three- and six-fold, respectively, greater than those associated with open bay locations. The target dioxin-like and estrogenic compounds measured in raw extracts of sediments accounted for approximately 20% and 40% of the activities measured in the sediment extracts. The results suggest that a combination of instrumental and bioanalytical measurements of dioxin-like and estrogenic compounds is a valuable approach to screen, identify, and prioritize the risks posed by contaminants in complex environmental matrices.
    Ecotoxicology and Environmental Safety 08/2005; 61(3):366-79. · 2.20 Impact Factor
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    ABSTRACT: Persistent organic pollutants and alkylphenols (APs) were determined in sediment and water samples from Onsan Bay, Korea, by using instrumental analysis and in vitro gene expression cell bioassay. Polycyclic aromatic hydrocabons (PAHs) were the predominant compounds in sediments with concentrations as great as 573 ng/g dry weight. The PAH concentrations were elevated in sediment from inland rivers that flow through Onsan City (mean: 116 ng/g dry wt) and discharge into Onsan Bay. Concentrations of polychlorinated biphenyls (PCBs) in sediments ranged from <1.00 to 56.2 ng/g dry weight. Among different organochlorine (OC) pesticides analyzed (hexachlorobenzene, hexachlorocyclohexanes, chlordanes, and DDTs), DDT concentrations were the greatest, ranging from <0.01 to 7.58 ng/g dry weight. The spatial gradient of contaminant concentrations suggested that streams and rivers are the major sources of PCBs, PAHs, and APs to the bay. Maximum concentrations of nonylphenol, octylphenol, and bisphenol A in sediments were 860, 11, and 204 ng/g dry weight, respectively. Screening of Onsan Bay sediment samples for dioxinlike activity with the H4IIE-luc in vitro cell bioassay revealed that 17 of 22 samples contained significant dioxinlike activity. Further fractionation of sediment extracts indicated that mid-polar and more polar fractions were responsible for the significant dioxinlike activity. Based on a mass balance analysis, PAHs apparently accounted for only a small portion of dioxinlike responses elicited by sediment extracts. Only one raw extract of sediment elicited a significant estrogenic response by MVLN cells. The combination of instrumental analysis and in vitro bioassay was useful to assess sediment quality and characterize the causative agents or potential toxic compounds present.
    Environmental Toxicology and Chemistry 09/2002; 21(9):1796-803. · 2.62 Impact Factor
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    Jinsoon Park, Chul-Hwan Koh
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    ABSTRACT: A study was performed to better understand the taxonomy and diversity of the diatom genus Amphora (Bacillariophyceae) from Korean coastal environments. Samples were taken from six locations at Saemangeum tidal flats on the west coast of Korea. Light microscopic (LM) and scanning electron microscopic (SEM) observations revealed a total of 23 Amphora species. Thirteen were identified to the species level, and ten to the genus level. Three Amphora species viz. A. arenicola, A. beaufortiana and A. maletractata var. constricta were recorded for the first time in Korea. All the Amphora species were listed and presented with morphological descriptions, dimensional information and photographic information.
    Ocean Science Journal 47(2).

Publication Stats

249 Citations
28.93 Total Impact Points

Institutions

  • 2002–2014
    • Seoul National University
      • • Department of Earth and Environmental Sciences
      • • College of Natural Sciences
      Sŏul, Seoul, South Korea
  • 2010
    • University of Saskatchewan
      • Department of Veterinary Biomedical Sciences
      Saskatoon, Saskatchewan, Canada