Sediment In Korea Research Articles

Development and validation of freshwater sediment quality assessment guidelines for trace elements in Korea

Sediment quality assessment guidelines(SQAGs) for seven trace elements were suggested to build an assessment system of freshwater sediment quality for a regulatory program in Korea. In this study, current one-step SQAGs were divided into three levels based on the probability of toxicity occurrence, namely, the threshold-effect-level(TEL), the probable-effect-level(PEL), and the apparent-effect-threshold(AET). A sediment toxicity database consisting of field-collected sediments and toxicity results from three different species were used to derive TEL, PEL, and AET. The ambient background concentrations of trace elements in freshwater sediments were used instead of the TEL values because TEL values were lower than the ambient background levels. To validate the reliability of the new SQAGs, a separate sediment toxicity database based on G. sobaegensis was used. When the mean quotient value for the PEL was 0.34, the reliability reached a maximum of 87% with a positive predictive value of 94% and a negative predictive value of 85%. These results showed the newly derived SQAGs were very useful for assessing and predicting the toxicity of field sediments in Korea. Finally, ambient background concentrations, a mean quotient of PEL of 0.34, and AETs were used to classify the quality of the field-collected sediments into four categories.

Grain size distribution and chemistry of the brackish Lake sediment in Korea

To determine the grain size distribution and chemical characteristics of bottom surface sediments in shallow brackish lagoons, we studied sediment samples collected from the entire horizontal lake area and in vertical profiles from three stations in Lakes Youngrang and Hwajinpo, on the eastern coast of Korea. Vertical and horizontal grain size distributions of the bottom sediments indicated predominantly sand- and silt in both lakes. The vertical distribution of C/N ratios ranged from 6.14 to 11.92 in Lake Youngrang, and 6.74 to 12.34 in Lake Hwajinpo. The horizontal distribution of C/N ratios in Lake Youngrang ranged from 6.1 to 17.6, whereas they ranged from 4.4 to 12.1 in Lake Hwajinpo. C/N ratios showed locally different responses to the origin of allochthonous (partial region) and autochthonous (entire region) organic materials. Horizontally, bottom sediment with low δ<sup>13</sup>C and high δ<sup>15</sup>N in Lake Youngrang were likely to be influenced by autochthonous organic material derived from primary production, and would be affected by N inputs from sources. In contrast, high δ<sup>13</sup>C and low δ<sup>15</sup>N sediments in Lake Hwajinpo were likely to be influenced by cyanobacteria.

Human Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) from Road Dust Sediments in Korea

Human Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) from Road Dust Sediments in Korea

A report of 35 unrecorded bacterial species isolated from sediment in Korea

A report of 35 unrecorded bacterial species isolated from sediment in Korea

Assessment of Polycyclic Aromatic Hydrocarbons Pollution in Lake and Reservoir Sediments in Korea

Polycyclic aromatic hydrocarbons (PAHs) are pollutants that require management as they are continuously formed by natural and anthropogenic processes. We assessed PAH pollution in freshwater sediment in major lakes and reservoirs of Korea. We collected samples of surface sediment in spring 2018; these were sieved to obtain sand, silt and clay (<2 mm). We extracted dry sediment using Hexane:Acetone(1:1) and analyzed the concentration of 16 PAHs by GC-MS. Measured concentration of PAHs was compared with threshold effect concentration(TEC) and probable effect concentration (PEC), and concentration ratio of chemical species was analyzed to track source. PAH concentrations ranged from 13 ng/g-dw to 1 337 ng/g-dw, (median 123 ± 204 ng/g-dw),which are below TEC and are similar or slightly lower than those reported by previous studies. At most sites, the dominant PAH source was natural combustion such as forest fires rather than anthropogenic such as petroleum. In contrast, the site with the highest PAH concentration (1 337 ng/g-dw) in Dae-am reservoir indicated natural and anthropogenic sources. Pollution levels of PAHs in reservoirs and lakes in Korea is not of concern in general. However, some sites with PAHs from anthropogenic sources need to be monitored to investigate possible increase in PAH concentrations in future. Key Words: PAHs, Sediment, Pollution assessment, Pollution evaluation guideline, Composition ratio of 16 PAHs

Changes in exoskeleton surface roughness and expression of chitinase genes in mud crab Macrophthalmus japonicus following heavy metal differences of estuary

Risk assessment of heavy metals is important for the health evaluation of inhabiting species in aquatic ecosystem. This study investigated whether chitin exoskeleton of mud crab Macrophthalmus japonicus is affected by heavy metals in estuary sediments in Korea. We compared heavy metal concentrations and analyzed the expression of M. japonicus chitinase genes, which play the crucial role in the formation of chitin exoskeleton. Concentrations of heavy metals were highly observed in crab body inhabiting Hampyeong among estuarine sites. High expressions of chitinase 1 were observed in crab gill and hepatopancreas from Myodo, which is the site with the lowest concentration of heavy metal in crab body. The surface roughness of the exoskeleton decreased with the increased concentration of heavy metals accumulated in the crab body. These results suggest that the total bioconcentration of heavy metals in crabs affected the expression of chitinase genes and changes in the exoskeleton surface roughness.

Effects of Microbial Growth Conditions on Synthesis of Magnetite Nanoparticles using Indigenous Fe(III)-Reducing Bacteria

Recent researches have shown that microbe–metal interactions play an important role in metal cycling and biomineralization in subsurface environments. The objective of this research was to study the effects of microbial growth conditions for size control on the synthesis of magnetite nanoparticles using Fe(III)-reducing bacteria enriched from intertidal flat sediments in Korea. The microbial formation of the magnetite nanoparticles was examined under various incubation temperatures (8–35 °C), concentrations (20–60 mM) of magnetite precursor, medium pHs (6.5–8.5), and incubation times (0–3 weeks). The Fe(III)-reducing bacteria formed 2~10 nm-sized magnetite (Fe3O4) by reduction of 40 mM akaganeite, especially under the conditions at 25 °C and medium pH = 8.5 within a 1-week incubation time. The magnetite nanoparticles formed by microbial processes exhibited superparamagnetic behavior.

Uliginosibacterium sediminicola sp. nov., isolated from freshwater sediment.

Strain M1-21T is a Gram-stain-negative, strictly aerobic and short-rod-shaped bacterium, motile by means of a single polar flagellum; it was isolated from freshwater sediment in Korea. It grew at 10-40 °C (optimum 25 °C), pH 6.0-8.0 (optimum pH 7.0) and with 0-0.75 % (w/v) NaCl (optimal growth occurred in the absence of NaCl) on R2A agar, and it accumulated poly-β-hydroxybutyrate granules inside the cells. According to 16S rRNA gene sequence analysis, strain M1-21T showed highest sequence similarity with Uliginosibacterium gangwonense (94.7 %) and Uliginosibacterium paludis (94.4 %). Phylogenetic analysis of the 16S rRNA gene sequences revealed that strain M1-21T belongs to the genus Uliginosibacterium. The DNA G+C content of strain M1-21T was 61.9 mol%. The predominant respiratory quinone was ubiquinone-8. The major fatty acids (>10 % of the total) were C16 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Strain M1-21T showed distinct phenotypic characteristics that differentiated it from species of the genus Uliginosibacterium. Based on these results, strain M1-21T represents a novel species of the genus Uliginosibacterium, for which the name Uliginosibacterium sediminicola sp. nov. is proposed. The type strain is M1-21T (=KACC 19271T=JCM 32000T).

Complete genome sequence and analysis of three kinds of β-agarase of Cellulophaga lytica DAU203 isolated from marine sediment

Cellulophaga lytica DAU203 (KACC 19187), isolated from the marine sediment in Korea, has a strong ability to degrade agar. The genome of C. lytica DAU203 contains a single chromosome that is 3,952,957bp in length, with 32.02% G+C contents. The genomic information predicted that the DAU203 has the potential to be utilized in various enzymatic industries.

Offsets in radiocarbon ages between plants and shells from same horizons of coastal sediments in Korea

To measure the spatial and chronological changes of the reservoir effect around the Korean Peninsula, the radiocarbon ages of 38 marine shell and terrestrial plant pairs from the same horizons of six cores of Holocene sediments collected from the southern coast and western coast sites of the peninsula were measured. These reservoir ages (R) were distributed in the range of 430±190 yrs within 60±60 to 1000±60yrs starting in 9000cal BP. The average R values of the cores obtained from large rivers, such as the S13 and YAR-4 cores (340 and 190yrs), were clearly smaller than the R values of the sites far from a large river, such as the S15 and W09 cores (470 and 650yrs). This is thought to be associated with the mixing process of old brine and young freshwater. On the other hand, the R values of the S13, W17, and YAR-4 cores gradually increased during the time span from 6700 to 8200cal BP. The R values for the S15 core also increased in the period from 2800 to 3800cal BP. Such tendencies result from the mixing ratio increase of brine due to the rising sea level.

Genomes of Alteromonas australica,a world apart

BackgroundAlteromonas is a genus of marine bacteria that is very easy to isolate and grow in the laboratory. There are genomes available of the species Alteromonas macleodii from different locations around the world and an Alteromonas sp. isolated from a sediment in Korea. We have analyzed the genomes of two strains classified by 16S rRNA (>99% similarity) as the recently described species Alteromonas australica, and isolated from opposite ends of the world; A. australica DE170 was isolated in the South Adriatic (Mediterranean) at 1000 m depth while A. australica H17T was isolated from a sea water sample collected in St Kilda Beach, Tasman Sea.ResultsAlthough these two strains belong to a clearly different species from A. macleodii, the overall synteny is well preserved and the flexible genomic islands seem to code for equivalent functions and be located at similar positions. Actually the genomes of all the Alteromonas species known to date seem to preserve synteny quite well with the only exception of the sediment isolate SN2. Among the specific metabolic features found for the A. australica isolates there is the degradation of xylan and production of cellulose as extracellular polymeric substance by DE170 or the potential ethanol/methanol degradation by H17T.ConclusionsThe genomes of the two A. australica isolates are not more different than those of strains of A. macleodii isolated from the same sample. Actually the recruitment from metagenomes indicates that all the available genomes are found in most tropical-temperate marine samples analyzed and that they live in consortia of several species and multiple clones within each. Overall the hydrolytic activities of the Alteromonas genus as a whole are impressive and fit with its known capabilities to exploit sudden inputs of organic matter in their environment.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-483) contains supplementary material, which is available to authorized users.

Characterization of a novel cold-active esterase isolated from swamp sediment metagenome

A functional screen of a metagenomic library from "Upo" swamp sediment in Korea identified a gene EstL28, the product of which displayed lipolytic properties on a tributyrin-supplemented medium. The EstL28 sequence encodes a 290 amino acid protein (designated as EstL28), with a predicted molecular weight of 31.3 kDa. The encoded EstL28 protein exhibited the highest sequence similarity (45 %) to a hydrolase found in Streptococcus sanguinis. Phylogenetic analysis indicated that EstL28 belongs to a currently uncharacterized family of esterases. Within the conserved α/β-hydrolase 6 domain, the EstL28 retains the catalytic triad Ser₁₀₃-Asp₂₄₈-His₂₆₈ that is typical of esterases. The Ser103 residue in the catalytic triad is located in the consensus pentapeptide motif GXSXG. The purified EstL28 enzyme worked optimally at 35 °C and pH 8.5 and remained stable at temperatures lower than 20 °C. The catalytic activity of EstL28 was maximal with p-nitrophenyl butyrate, indicating that it was an esterase. This enzyme also exhibited stable activity in the presence of methanol, ethanol, isopropanol, and dimethyl sulfoxide. Therefore, the level of stability in organic solvents and cold temperature suggests that EstL28 has potential for many biotechnological applications.

오염 준설퇴적토의 입자분리기술에 관한 연구

As sediment contamination problems have recently been raised in Korea, the need for technologies to remove contaminants in sediments has increased. Contaminated sediments in Korea has been annually dredged and treated using processes of coagulation/flocculation, sedimentation on barges, dewatered and dried at prepared site, and then disposed at a landfill site, which is very costly, and only a limited landfill space available in Korea. Contaminants in media containing a high percentage of silt and clay sized particles, typically, are strongly adsorbed on the particles and difficult to remove. Particle separation processes that separate the fine clay and silt particles from the coarser sand and gravel and concentrate the contaminants into a smaller volume of sediment that can be further treated of disposed of, are very effective in the post step processes. In this study are to test the feasibility of treating dredged sediments using a hydrocyclone process, and to estimate design parameters for a pilot scale test. A hydrocyclone was operated to separate larger particles from the sediments. It was found that the particle separation was greatly affected by the solid contents and inlet pressure in the hydrocyclone.

Development of freshwater sediment management standards for organic matters, nutrients, and metals in Korea

Korean water quality managers are required to promptly develop national assessment standards for freshwater sediment quality due to the Four Major River Restoration Project in Korea in 2009. We conducted this study to develop sediment management standards (SMSs), determining obviously and severely polluted sediment, which could have adverse impacts on water quality and aquatic ecosystem. The SMSs values were derived from the 95th percentile of concentration distribution for organic matter and nutrients in sediment quality database. For the SMSs of metals, foreign sediment quality guidelines (SQGs) were adopted. As a result, 13% for loss on ignition (LOI), 1,600 mg/kg for total phosphorus (TP), and 5,600 mg/kg for total nitrogen (TN) were set as the SMSs for freshwater sediment in Korea. These values were higher than the range of heavily polluted sediment from USEPA Region 5 guideline derived by the similar approaches for the Great Lakes harbor sediments, and similar or lower than the severe effect level (SEL) from provincial sediment quality guideline (PSQG) of Ontario, Canada by screening level concentration (SLC) approach. However, SMSs in the present study are appropriate considering the concentration ranges and the Korean SMSs’ definition for freshwater sediments in Korea. The Puget Sound marine sediment cleanup screening level (CSL) in Washington State, USA were adopted as the Korean SMSs for As (93 mg/kg), Cd (6.7 mg/kg), Cr (270 mg/kg), Cu (390 mg/kg), Pb (530 mg/kg), and Zn (960 mg/kg) in freshwater sediments. Hg concentration (0.59 mg/kg) of CSL was too low to determine the polluted freshwater sediments in Korea, and the SEL of Ontario, Canada for mercury concentration (2 mg/kg) was selected as the SMS for Hg. These values were found reasonable through the assessment of applicability with the datasets from locations directly affected by obvious point sources. These results indicate that SMSs for organic matter, nutrient, and metals derived within the present study can successfully determine obviously and severely polluted sediment in Korea. However, the SMSs have limits to specifically determine the effects of polluted sediment on water quality and aquatic ecosystem in Korea. Thus, we will revise and specify SMSs considering those effects and further sediment quality assessment framework in the near future.

Effects of Ammonia on Fertilization, Development, and Larval Survival in the Northern Pacific Asteroid, Asterias amurensis

For developing a complementary test organism to sea urchin during winter in Korea, sensitivities of sperm, embryo, and larvae of Asterias amurensis to un-ionized ammonia were evaluated. The EC₅₀s (Mean ± SD, n = 3) for fertilization and development were 169 ± 62 and 70 ± 19 μg/L, respectively. The 48, 72, and 96-h LC₅₀s for larval survival were 1,674 ± 583, 498 ± 221, and 336 ± 107 μg/L, respectively. The sensitivities of fertilization, development, and larval survival tests with A. amurensis are higher than or comparable to those of sea urchin and other taxonomic groups. Therefore, fertilization, development, and larval survival tests using A. amurensis are suitable for assessing pore water toxicity of marine sediments in Korea.

Stakelama sediminis sp. nov., isolated from tidal flat sediment

A novel bacterial strain designated CJ70(T) was isolated from tidal flat sediment in Korea. A polyphasic approach was used to identify this strain taxonomically. The isolate was Gram-stain-negative, strictly aerobic, yellow-pigmented, rod-shaped and non-motile. Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain CJ70(T) was related most closely to Stakelama pacifica JLT832(T) with 95.7 % similarity and formed an independent phyletic line from recognized species of the genus Sphingomonas, comprising a clade with Stakelama pacifica, which is the only recognized species of the genus Stakelama. The predominant cellular fatty acids of strain CJ70(T) were C(18 : 1)ω7c (60.0 %), C(16 : 0) (21.2 %) and C(14 : 0) 2-OH (5.8 %). The major isoprenoid quinone was ubiquinone-10. The G+C content of the genomic DNA was 61.4 mol%. The results obtained from this study suggested that strain CJ70(T) represents a novel species of the genus Stakelama, for which the name Stakelama sediminis sp. nov. is proposed. The type strain is CJ70(T) ( = KACC 16559(T) = JCM 18079(T)).

Variations in quartz OSL components with lithology, weathering and transportation

The signal properties of quartz optically stimulated luminescence (OSL) vary from sample to sample, and even from grain to grain, in terms of, for example, signal intensity or the composition of OSL signal components. However, the cause of the variation in quartz OSL properties is not well understood. Here, we report our experimental observations of continuous wave and linearly modulated OSL signals in quartz grains from fresh bedrocks, saprolites, and sediments in Korea. The OSL signals in quartz grains from both fresh bedrocks and saprolites in the granitic and metamorphic rocks are dominated by slower OSL components, with no fast OSL component. By contrast, the OSL signals in quartz extracts from sandstones are predominantly composed of fast OSL components. Quartz extracts derived from thermally metamorphosed or diagenetically recrystallised sandstones, however, tend to emit weaker OSL signals, a property related to intense slower OSL components. Along the fluvial transportation path, slower OSL components dominate near the host granite, but their absolute/relative intensity decreases with a simultaneous increase in the fast OSL component with transportation distance. OSL signal characteristics suitable for dating appear to be acquired during sedimentary processes after the liberation of quartz grains from granitic and metamorphic bedrock. Therefore, granitic and metamorphic quartz grains should be transported a sufficient distance for the fast OSL component to be sensitised. However, unless they have been affected by post-thermal metamorphism and recrystallisation, the OSL signal properties of quartz grains released from Cretaceous sedimentary rocks seem to be suitable for OSL dating, regardless of the transportation distance.

Mesozoic detrital zircon U‐Pb ages of modern river sediments in Korea: implications for migration of arc magmatism in the Mesozoic East Asian continental margin

Terra Nova, 24, 156–165, 2012AbstractU‐Pb ages of detrital zircons collected from the sediments of seven major South Korean rivers were analysed to infer the temporal and spatial distribution of Mesozoic arc magmatism related to the subduction of the palaeo‐Pacific plates. Mesozoic detrital zircon U‐Pb ages indicate continuous arc magmatic activity in the Korean Peninsula throughout the Mesozoic era (249–72 Ma), except for a magmatic gap during 120–162 Ma, with NW–SE spatial migration of the arc magmatic centres: trenchward migration in both the Triassic and the Cretaceous periods, and inland‐directed migration in the Jurassic period. A comparison of these results with the magmatic ages in the adjacent regions such as northeastern China and southwestern Japan suggests that subduction modes of the palaeo‐Pacific plates were changed in the Mesozoic East Asian continental margin due to buoyancy differences caused by the subduction of the Farallon–Izanagi plate ridge or oceanic plateaus and their subducting location shifting with time.

Levels of Human Steroid Hormones in Water and Sediment From 4 Major Rivers in Korea

PP-30-122 Background/Aims: Steroid hormones remained in river water or soil may influence endocrine disrupting effects to ecological system even though low level of concentration. This study was performed to assess the residual level of 4 steroid hormones at river water and sediment. Methods: Estrone (E1), 17-β-estradiol (E2), estriol (E3), and 17-α-ethinylestradiol (EE2) were analyzed at water (n = 80) and sediment (n = 8) from 4 major river in Korea by LC-MS/MS technique. Water and sediment samples were prepared by continuous solid phase extraction method subsequent by liquid-liquid extraction. Results: The concentration of steroid hormone ranged ND ∼59.4 ng/L for E1, ND ∼52.8 ng/L for E2, ND ∼8.6 ng/L for E3 in river water and ND ∼5.75 ng/g for E1, ND ∼1.29 ng/g for E2 in sediment samples, respectively. EE2 was not found at any of the samples. The occurrence rate of E1 was most high; 21.3% for river water samples and 75% for sediment samples. Conclusion: We detected low concentration of steroid hormones in river water sediments in Korea.

Scoping the effective marine environmental assessment of dredging and ocean disposal of coastal sediments in Korea

The application of scoping is reviewed to improve the efficiency and rationality of the marine environmental impact assessment system applied to the dredging of coastal sediments and the oceanic disposal of dredged material in Korea. Both the impact levels and those items requiring assessment vary in response to differing goals of the coastal activities involved and also to changes in the characteristics of different marine environments. As a consequence, different assessment fields need to be emphasized for evaluation of the impact that both dredging and dumping might have on the sites involved. The status of current assessment procedures is examined and its problems are diagnosed. Following a survey of interested parties and a review of case studies of the oceanic disposal of dredged sediment in other countries, checklists of core assessment items are proposed as part of a revamped review process, along with improvements to the assessment system.