• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.175-184
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• 2013

Organic carbon and total nitrogen stable isotope ratios of suspended materials were determined at 3 stations (from Mongtan Bridge to Youngsan river estuary barrage) (n=6, each) from November 2008 to August 2009, in order to understand the origin of particulate organic matter at the Estuary of Youngsan River. Allochthonous organic matter, ammonia-N and silicate were increased after heavy rain (in August). Carbon isotope ratios were significantly different between stations in November and August, and it was possible to determine the origin of organic matter. The heavier nitrogen isotope ratios, as well as higher phosphate concentrations, were found in November than other sampling times. Livestock wastewater and farmland input was likely the main causes of these high values. In addition, YS3 station, the nearest site to estuary barrage, appears to be affected by a substantial amount of livestock wastewater and farmland input, considering that nitrogen isotope ratios were heavier than those at the upper sites. These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the determination of organic matter origin in aquatic environments.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.91-101
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• 2020

Stormwater runoff is known as a major non-point water pollution source that transports heavy metals, which have accumulated in road surface, to stream and coastal area. Dissolved and particulate metals in stormwater runoffs have been investigated to understand the outflow characteristics of heavy metals during rainfall events and to identify their pollution sources. The concentration of dissolved Co and Ni decreased after the outflow with high concentrations at the beginning of the rainfall, and other metals showed different characteristics depending on the rainfall and rate of discharge. Particulate metals showed a similar trend with the temporal variation of suspended solids concentration in stormwater runoffs. The results of geo-accumulation index (I_geo) indicated that the stormwater runoffs from industrial region were very highly polluted with Cu, Zn and Cd. As a result of comparing the metal concentrations of <125 ㎛ for road dust near the study area, Cu, Zn and Cd were originated from inside of metal manufacturing facilities rather than traffic activities at road surface and these metals accumulated on the surface area of facilities were transported to the water environments during stormwater event. The average discharged amounts of heavy metals for one rainfall event were Cr 128 g, Co 12.35 g, Ni 98.5 g, Cu 607.5 g, Zn 8,429.5 g, As 6.95 g, Cd 3.7 g, Pb 251.75 g, indicating that metal runoff loads in the stormwater runoffs are closely related to surrounding industry types.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.279-287
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• 1993

Daily variation of particulate organic carbon(POC) and some factors controlling its level were examined for a semi-enclosed bay(Wonmun Bay, south coast of Korea), in which a lot of suspended oyster culture farms existed, in September, 1992. Observations were made at hourly interval. In spite of the relatively short survey period, strong short-term variation of POC concentration could be observed. Concentrations of POC were the range of $58{\sim}582{\mu}g/l(average 272{\mu}g/l)$ and their variation pattern was similar to those of chlorophyll a with the range of $0.90{\sim}7.25{\mu}g/l(average 3.35{\mu}g/l)$. The low C/N ratios also suggested that marine microalgae was a major component of POC for Wonmun Bay. Primary production, average $1.97\;gC/m^2/day$, was the main source of POC beacuse the supply of POC via freshwater input and exchange with the outer part of the bay was little. Oyster population also excreted a small amount of POC. About $40\%$ of produced POC was decomposed heterotrophically. Another important cause for the fluctuation of observed POC was tidal cycle. Considerable POC, which amounted $37\%$ of produced POC, was lost from the bay due to flushing by tidal cycle. It was also calculated that about $16\%$ was transported onto the sediment. It seemed that a part of POC was consumed by oyster and other heterotrophs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.1
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• pp.57-69
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• 2001

The chemical, elemental and biochemical components of the suspended particulate matter (SPM) were investigated in order to quantify particulate organic matter (POM) and assess diet quality for suspension feeders in the southern coastal bay systems of Korea where the marine farming of the suspension feeders are most active, The intense field observation program was carried out seasonally in the three coastal bay systems of Chinhae, Gosung and Kangjin bays, The SPM was characterized as collective properties of organic carbon (POC), nitrogen (PON), phosphorus (PP) and more refined collective properties of protein (PPr), carbohydrate (PCHO) and chlorophyll a (Chl a) compound. Although the three coastal bays are regarded as phytoplankton based ecosystem, the SPM is not composed entirely with phytoplankton cells. Due to the shallow water depth, resuspension of bottom sediment contributes significantly to some of the regions. Therefore, concentration of SPM in the surface water did not co-vary with Chl a or PPr, PCHO. In general, temporal variation of POC, PON and Chl a contents in seawater were closely associated with phytoplankton biomass in the three coastal bays, However, PPr and PCHO contents in seawater were higher in Chinhae bay than in Gosung and Kangjin bays and Chl a PPr-N ratio was higher in Chinhae bay than in Kosung and Kangjin bays, since Chinhae bay is more eutrophicated than other bays. Average C : N ratios from regressions of POC and PON of SPM were 6.6, 6.6 and 5.0 in Chinhae, Gosung and Kangjin bays, respectively. SPM in Chinhae and Gosung bays appears to be made of largely phytoplankton cells and SPM in Kangjin bay appears to be contributed from the bacterial biomass due to the shallow water depth. N : P ratios from regressions of PON and PP of SPM were 10.8 and 14.7 in spring, and 18.2 and 24.6 in Chinhae and Gosung bays, respectively. With respect to the hypothetical Redfield molecule, phytoplankton appears to be limited by the lack of N and f in spring and summer, respectively, in the two bays, In Kangjin bay, N : P ratios from regressions of PON and PP of SPM were varied from 6.3 to 12.8 throughout the year. The low N : P ratio with resepct to the hypothetical Redfield molecule, phytoplankton growth appears to be limited by the lack of N-nutrients.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.4
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• pp.187-198
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• 2017

Dissolved and particulate organic carbon concentrations and fluxes were measured and estimated for the Yeongsan River during 2006~2015. The dissolved organic carbon (DOC) concentrations ranged from 2.49 to $4.39mg{\cdot}C/L$ with a variance of 30.1% (${\sigma}_x/\bar{x}$), and showed a simple correlation to algal bloom and precipitation. The particulate organic carbon (POC) concentrations had gradually decreased from 6.68 to $0.19mg{\cdot}C/L$ for 10 years, and changed definitely with weir construction in 2011. Based on the relationships between POC and suspended particulate matters and between POC and chlorophyll-a, we found out that the distinct variation of the origin and composition of POC was caused by stagnation and screening effect of the dammed river. The total organic carbon (TOC) concentrations dropped to 52.3% (from 8.26 to $3.94mg{\cdot}C/L$) as the POC concentrations diminished to more than 94.8% after weir construction, in which the DOC forms up to 90.9%. The fluxes of TOC, based on the relationship between the annual TOC concentration and the discharge of Yeongsan dike sluice, were $2.56{\sim}19.41{\times}10^9g{\cdot}C/yr$, and showed a great deal of variability in 2011. Since then the TOC flux dropped to $5.40{\times}10^9$ (2011~2015) from $14.54{\times}10^9g{\cdot}C/yr$ (2006~2010). These results suggest that the weirs trapped annually $1.83{\times}10^9g{\cdot}C$ on a river bed, but released in great levels of dissolved organic form at their exits.

• 한국해양학회지
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• v.23 no.4
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• pp.159-168
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• 1989

Nutrients and trace metals of copper and nickel were investigated in the inner part of Deukryang Bay (southern coast of Korea) during 1980-81. This region is characterized as permanently well-mixed coastal waters. Because of this hydrographic condition, nutrients and trace metals showed interesting features in their seasonal cycles. The concentrations of dissolved nutrients and dissolved trace metals were higher in fall and winter than in spring and summer, while the concentrations of suspended particulates and particulate trace metals were much higher in winter than the rest of the year. Seasonal changes of nutrients suggest that the addition of nutrients via freshwater runoff during the late summer enhanced phytoplankton growth and subsequently caused phytoplankton blooms in winter. Depletion of nitrate seems to terminate phytoplankton bloom in this region, and copper and nickel appeared to be controlled by the in situ primary production.

• Journal of Environmental Science International
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• v.23 no.2
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• pp.275-289
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• 2014

Asian dust (or yellow sand) occurring mainly in spring in East Asia is affected by the distribution of weather systems. This study was performed to investigate the characteristics of suspended particulate for Asian dust at Busan, Korea in 20 March 2010, which was one of the extreme case for the last 10 years. There was used the data of weather chart, satellite, automatic weather system (AWS), $PM_{10}$, laser particle counter (LPC), and backward trajectories model. In synoptically, the high pressure was located in the northwestern part and low pressure was located in the northeastern part of Korea. The strong westerly winds from surface to upper layer makes it possible to move air masses rapidly. Air masses passing through Gobi Desert in Mongolia and Inner Mongolia plateau covered the entire Korean peninsula. As the results of aerosol analysis, $PM_{10}$ concentration at Gudeok mountain in Busan was recorded $2,344{\mu}g/m^3$ in 2300 LST 20 March 2010 and their concentration was markedly increased at coarse mode particle. In surface condition, westerly wind about 3 ~ 5 m/s was dominant and small particles of $0.3{\sim}0.5{\mu}m$ were distributed on the whole. In heavy metal components analysis, the elements from the land was predominated.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.252-261
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• 1991

A particle trajectory model to simulate two-phase particle-laden crossjets into two-dimensional horizontal free stream has been developed to study the variations of the jet trajectories and velocity variations of the gaseous and the particulate phases. The following conclusions may be drawn from the predicted results, which are in agreement with experimental observations. The penetration of the two-phase jet in a crossflow is greater than that of the single-phase jet. The penetration of particles into the free stream increases with increasing particle size, solids-gas loading ratio and carrier gas to free stream velocity ratio at the jet exit. When the particle size is large, the solid particles separate from the carrier gas , while the particles are completely suspended in the carrier gas for the case of small size particles. As the particle to carrier gas velocity ratio at the jet exit is less than unity, the particles in the vicinity of the jet exit are accelerated by the carrier gas. As the injection angle is increased, the difference of the particle trajectory from that of the pure gas becomes larger. Therefore, it can be concluded that the velocities and trajectories of the particle-laden jets in a crossflow change depending on the solids-gas loading ratio, particle size, carrier gas to free stream velocity ratio and particle to gas velocity ratio at the jet exit.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.171-176
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• 1999

To estimate the residence times of aerosols in air, the activities of $^{210}Pb$ and $^{210}Po$ in aerosols were measured at 4 sites in Pusan. All aerosol samples were collected by a high volume air sampler from January to October 1996. The activities $^{210}Pb$ and $^{210}Po$ in Pusan were varied from 11.77 to 67.57 dpm/1000$m^3$ and from 2.63 to 15.91 dpm/1000$m^3$, respectively. The mean activities were 34.62 dpm/1000$m^3$ for $^{210}Pb$ and 8.24 dpm/1000$m^3$ for $^{210}Po$. The highest values of the activities of $^{210}Pb$ and $^{210}Po$ were appeared at P3 site and the lowest values at P4 site. During the sampling period, the trends of the activities of $^{210}Po$ and $^{210}Pb$ were similar to total suspended particulate matter(TSP) concentrations. The mean residence times of atmospheric aerosols calculated from $^{210}Po$/$^{210}Pb$ activity ratio was about 60~80 days in Pusan. The longest residence time of atmospheric aerosols was in January because of the lack of rainout and washout, but the shortest residence time was in August, largely due to scavenging effect by frequent rains. The activities of $^{210}Po$ and $^{210}Pb$ in atmospheric aerosols were different in time and space, which seems that the distribution of $^{210}Po$ and $^{210}Pb$ activities and scavenging processes in air may be controlled by the local and meteorological conditions.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.1
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• pp.73-79
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• 1986

This study is carried out to determine the concentration of the ozone and the factors affecting the variation of ozone concentration in the ambient air in Seoul. The one-hour average concentration of ozone $(O_3)$, sulfur dioxide $(SO_2)$, nitrogen oxides (NO and $NO_2$), suspended particulate (TSP), carbon monoxide (CO) and non-methane hydrocarbon (NMHC) at 5 sites in Seoul measured from September to October in 1983 and 1984 were analysed statistically along with meteorological data for the same period. The results were as follows; 1. The average concentrations of ozone at 5 sites during the period ranged from 3.3 to 9.1 ppb, they were below 20 ppb of the ambient air quality standard of Korea. 2. The maximum hourly concentration of ozone occurred between 2 and 3 p.m. in a day and concentration at night were very low but higher concentrations were observed at around 4 a.m. 3. The concentration ratio between NO and $NO_2$ in Seoul was relatively lower than that for the cities of foreign countries reported so far. 4. The ozone concentration has negative correlationships with the concentration of other primary pollutants$(SO_2, NO, NO_2, CO and NMHC)$ in simple regression analyses. 5. The ozone concentration was positively correlated to wind speed, temperature and insolation intensity but negatively correlated to relative humidity. 6. Stepwise multiple regression analysis of the ozone concentration to the pollutants and meteorological factors indicate that insolation intensity and $[NO_2]/[NO]$ were the primary influencing factors. 7. The three factors of insolation intensity, $[NO_2]/[NO] and NO_2$ concentration had a significant combined effect on the ozone concentration $(r^2 = 0.47-0.57)$.