Jeongwon Kang

Atmospheric metal and phosphorus concentrations, inputs, and their biogeochemical significances in the Japan/East Sea.

Atmospheric metals and phosphorus over the southern Japan/East Sea were investigated in order to evaluate their sources, concentrations and inputs, and to identify their biogeochemical roles in this marginal sea. Aerosols were collected on the east coast of Korea from February 2002 to April 2003 (n=101) as well as at a remote island (Ulleung) and on a ship from February 2002 to June 2003 (n=13). The aerosols were analyzed for Al, Co, Cu, Ni, P, Pb and Zn. Simultaneous collections of aerosols at both coast and offshore were performed, and several high dust aerosols (Al>5 microg m(-3)) were collected at both regions. At the coastal site, both dust mineral and pollutants were transported by westerly winds from the Asian continent, but local emissions were significant (e.g., Cu, Ni, P and Zn) as well during the summer monsoon (May-August). The experimental relationships between the coast and offshore sites were defined. From these relationships, it was possible to obtain the annually averaged atmospheric metal and P concentrations over the southern Japan/East Sea, which has increased by over 2 times for the last decade. Through the estimation of atmospheric metal and phosphorus fluxes and comparisons with inputs from the Tsushima Warm Current, the atmospheric pathway was found to be a significant source for Al, Pb and Zn.

Atmospheric transport of water-soluble ions (NO3−, NH4+ and nss-SO42−) to the southern East Sea (Sea of Japan)

Atmospheric deposition of different types of aerosols over the southern East Sea has received little attention in terms of seawater biogeochemistry. We investigated the concentrations of water-soluble ions (NO3(-), NH4+ and nss-SO4(2-)) in the aerosols associated with air mass transport patterns arriving at the east coast of Korea, adjacent to the southern East Sea, in order to determine source regions affecting chemical composition of aerosols and to assess the atmospheric pathway as a significant controlling mechanism of the biogeochemistry in this marginal sea. Concentrations of certain elements (Al, Na, Ca, V, Zn and Pb) together with the water-soluble ions were measured in the aerosol samples (n=34) collected during the period March 2002-February 2003. The geometric mean concentrations of the water-soluble ions were NO3(-) 2.98 (0.56-16.22), NH4+ 1.42 (0.37-6.73) and nss-SO4(2-) 2.47 (0.17-17.35) microgm(-3). The backward trajectories revealed that air masses passing slowly over eastern China contributed more to increases in the concentrations of water-soluble ions than those associated with fast-moving northwesterly and maritime winds. Therefore, the correlation between the NH4+ and NO3+ concentrations increased, suggesting that gas-phase NH3 and HNO3 was forming fine-mode NH4NO3. The atmospheric N input accounted for approximately 10% of new production over the southern East Sea on an annual scale, while it accounted for over approximately 25% of new production during the water column stratification seasons (summer and early fall).

Effect of abalone farming on sediment geochemistry in the Shallow Sea near Wando, South Korea

Wando County has grown up to 93% of the total abalone produced in South Korea since the late 1990s; however, this production has been decreasing in recent years. The objectives of this study were to understand the potential contamination risks of abalone farming and to examine the influence of intensive abalone farming on sediment quality by analyzing grain-size composition, organic matter (total organic carbon (TOC), total nitrogen (TN), total sulfur (TS)) and heavy metal content, pH, and 210Pb geochronology. The results of organic matter analysis from surface and core sediment (length: 64 cm) showed that the area around the abalone farm had oxic marine-to-brackish conditions, but that the area directly below an abalone cage (location 7) had reductive conditions, with a C/S ratio of ~2. The average TN levels in the surface and core sediments were 0.25% and 0.29%, respectively, and this was predominantly due to the use of seaweed for feed. The low sediment pH (surface, 7.23; core, 7.04), indicates that acidification of the bottom sediment has gradually increased since the initiation of abalone farming and is likely due to the continuous accumulation of uneaten feed and feces. Heavy metal pollution was not apparent based on the examination of EF and Igeo, although the excess metal flux of Ni, Pb, Cu, Co, As, and Cd increased toward surface of the sediment core. These sediment changes may be caused by the rapid accumulation (sedimentation rate: 1.45 cm/year) of sludge discharged from the abalone farm and may be controlled by tidal currents, physiography, water depth, and tidal ranges.

Rare earth element fingerprints in Korean coastal bay sediments: Association with provenance discrimination

Rare earth elements (REEs: La-Lu) in surface sediments collected from the mouth and middle tidal flats of Gomso Bay, South Korea, in August 2011 and May 2012 were analyzed to investigate the fine-grained sediment provenance. The upper continental crust (UCC)-normalized light REEs (LREEs: La to Nd) were more enriched than the middle REEs (MREEs: Sm to Dy) and heavy REEs (HREEs: Ho to Lu), resulting in large (La/Yb)UCC (1.9 ± 0.4) to (Gd/Yb)UCC (1.4 ± 0.2) ratios. The monthly (La/Yb)UCC values differed between the mouth and middle tidal flats due to deposition of fine-grained sediments that originated from distant rivers (the Geum and Yeongsan) and the Jujin Stream, located on the southern shore of the inner bay. We observed relative reductions in the (La/Yb)UCC value and REE content in the sediments from the mouth of the bay compared with those from Jujin Stream sediments. Confined to the middle tidal flat around the KH Line of Jujin Stream, the sediments, most enriched in LREEs but depleted in Eu, were distributed in August as strong Jujin Stream runs. Here, we suggest that an increase in LREE/HREE and decrease in MREE/LREE ratios can be used as a proxy to identify the Jujin Stream provenance in mixed riverine sediments and to trace Jujin Stream sediments within the Gomso Bay tidal flat, especially in the summer rainy season.

Sedimentary mercury (Hg) in the marginal seas adjacent to Chinese high-Hg emissions: Source-to-sink, mass inventory, and accumulation history

We comprehensively investigated sedimentary Hg in Yellow and East China Seas (YECSs), which constitute potentially important depocenters for large anthropogenic Hg emissions from mainland China. A large dataset of Al-TOC-Hg concentrations led to an in-depth understanding of sedimentary Hg in the entire YECSs, including distribution and its determinants, source-to-sink, background levels, inventory in flux and budget, and accumulation history. Especially, the net atmospheric Hg flux to the sediments was estimated to be 1.3 × 10-5 g/m2/yr, which corresponded reasonably well to that calculated using a box model. About 21.2 tons of atmospheric Hg (approximately 4% of the total anthropogenic atmospheric Hg emissions from China) were buried annually in the YECS basin. This result implies that most of atmospheric Hg from China is transferred to the surface of the Pacific (including the East/Japan Sea and South China Sea) by the westerlies and, consequently, can play a critical role in open-sea aquatic ecosystems.

Benzene, Toluene, Ethylbenzene, Xylene, and Styrene (5VOCs) Distributions at the Barrier Island System in the Nakdong River Estuary, South Korea

ABSTRACT Lee, J.-H.; Jeong, K.-S.; Kang, J.; Park, K.-S., and Woo, H.J., 2017. Benzene, toluene, ethylbenzene, xylene, and styrene (5VOCs) distributions at the barrier island system in the Nakdong River estuary, South Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 89–93. Coconut Creek (Florida), ISSN 0749-0208. Total Volatile Organic Compounds (TVOCs) were extracted from 18 surface sediment samples collected in and around barrier island system in the Nakdong River Estuary (NRE) on the southeastern Korean Peninsula in May 2015. TVOC emissions from sediments were measured using a Thermal Desorption System-Gas Chromatograph-Mass Selective Detector (TDS-GC-MSD) for 30 min at 25°C at the National Center for Inter-university Research Facilities (NCIRF), Seoul National University, South Korea. The thermal extractor (Gerstel, Germany) was equipped with an adjustable oven (temperature, 25–350°C) to heat a glass tube containing the sample. TVOC concentrations ranged from 2.6 to 64.9 ng/g-dry weight (average, 13.2 ± 13.8 ng/g-dry weight), with benzene in the range 0.6 to 0.8 ng/g-dry weight (average, 0.7 ± 0.1 ng/g-dry weight), toluene in the range 0.4 to 1.3 ng/g-dry weight (average, 0.9 ± 0.3 ng/g-dry weight), and xylene in the range 0.0 to 0.8 ng/g-dry weight (average, 0.2 ± 0.2 ng/g-dry weight). No evidence of ethylbenzene or styrene was found at the sampling sites. TVOC concentrations were highest at Sinjado zone, at 64.9 ng/g-dry weight. This area corresponds to back-barrier fringe marsh sediments sorted by location and terrain. Although TVOC levels in many sediments were below the detection limit, this method can be used to estimate their behavior in marine environments. This monitoring in the NRE can draw the necessity of safety management and Sediment Guidance Values (SGVs) establishment as to contributing to remediation of contaminated sediments.

Seasonal Changes in Sediment Characteristics on the Tidal Flat in Geunso Bay, West Coast of Korea

ABSTRACT Woo, H.J.; Kang, J.; Lee, J.-H., and Jang, S., 2016. Seasonal changes in sediment characteristics on the tidal flat in Geunso Bay, west coast of Korea. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1412 - 1416. Coconut Creek (Florida), ISSN 0749-0208. Geunso Bay, located in Taean, western Korean Peninsula, is a semi-enclosed-type bay with a mean tidal range of about 6 m. Tidal flats are largely developed along the sides of the bay. A digital elevation model showed that 95% of the total area of the bay is tidal flat. Observations in both winter and summer of 2009 revealed that the surface sediments in the bay were mainly muddy sand, and the sediments were classified into five sedimentary facies: sandy silt, slightly gravelly sandy mud/sandy mud, slightly gravelly muddy sand/muddy sand, silty sand, and sand. In the eastern tidal flat, the annual sedimentation rate ranged from −71.3 to 12.4 mm/year, with a net erosion rate of −15.0 mm/year. Erosion was dominant on the tidal flat in the middle part of the bay, whereas deposition occurred in the western tidal flat in winter and spring, with a net deposition rate of 10.8 mm/year. Suspended sediments were supplied to the bay in relatively large amount in winter and spring and were transported in an anti-clockwise direction. Winter waves played a limited role in the seasonal variation in sedimentation due to the southwestward-opening bay mouth. It seems that the supply of suspended sediments and the circulation pattern of tidal currents are the most important factors for seasonal variations in sediments on the Geunso tidal flat.

Evaluation of CH 4 Flux for Continuous Observation from Intertidal Flat Sediments in the Eoeun-ri, Taean-gun on the Mid-western Coast of Korea

in theair sample collected in the chamber were measured using gas chromatography with an EG analyzer, model GS-23,within 6 hours of collection, and the other gases were measured in real time using a multi-gas monitor. The gasemission fluxes (source (+), and sink (-)) were calculated from a simple linear regression analysis of the changes inthe concentrations over time. In order to see the surrounding parameters (water content, temperature, total organiccarbon, average mean size of sediments, and the temperature of the inner chamber) were measured at the study site.On the first day, across three measurements during 5 hours 20 minutes, the observed CO

Trace metals (Co, Ni, Cu, Cd, and Pb) in the southern East/Japan Sea

Total dissolvable metals (Co, Ni, Cu, Cd, and Pb) in both surface waters and the water columns were acquired in the southern East/Japan Sea during a cruise around the Ulleung Basin in June 2001 to understand the spatial distributions of the metals. Concentrations in offshore surface waters were found to be Co 60 ± 12 pM, Ni 2.16 ± 0.25 nM, Cu 1.85 ± 0.55 nM, Cd 0.134 ± 0.018 nM, and Pb 155 ± 40 pM. Spatial distributions in surface waters showed that metal levels were generally enhanced at coastal sites in both Korea and Japan, where the metal distributions indicated complex patterns due to inputs, biogeochemical processes, and physical factors including upwelling. The Co distributions in the water columns seemed to be influenced predominantly by surface and bottom inputs, scavenged rather than regenerated at depth. For Cd, there was generally good agreement between the Cd and PO4 depth distributions, in agreement with the literature. The Cd/PO4 ratio from the water columns was found to be 0.133–0.203, lower than that in other marginal seas (e.g. the East/South China Seas and the Philippine Sea) of the western Pacific Ocean; this might be a result of the fast ventilation rate in this sea. The vertical Pb profile showed typical scavenged-type behavior with a surface maximum and deep minimum. From a comparison of inputs from the atmosphere and the Tsushima Warm Current, atmospheric deposition is substantial enough that it cannot be ignored, and its role in metal cycling is more significant in the offshore zone.