• Journal of Korean Society for Atmospheric Environment
• /
• v.10 no.1
• /
• pp.57-63
• /
• 1994

In order to comprehension of the behaviour of PAHs in air which is known as carcinogens and/or mutagens suspended Particulates in ambient air were collected by Anderson air sampler from 1992. 6 to 1993. 5 in Seoul. Ten species of PAHs( Phen, An, Fl, R, Py, BaAn, BaP, Chry, BeP, DiB(a, h)An, I123p) were analyzed to understand monthly variations of PAHs distribution of PAHs concentration according to particle size, and correlation between PAHs and independent charactierstics of PAHs The highest concentration of TSP was 155.58$\mu\textrm{g}$/㎥ in May and the lowest was 60$\mu\textrm{g}$/㎥ in August. Concentration of TSP was more affected by coarse particles in spring, otherwise which was more affected by fine particles in winter. According to results of anaylsis of samples that were collected by Anderson air sampler, concentration of PAHs was more high in winter than that in summer. In almost samples collected by Anderson air sampler, concentration of PAHs was more high in coarse particles than in fine particles, but BaP well known as carcinogenic matter had more high concentration in fine particles(56-97.5%) than that in coarse particles(2.5-46%). Correlation between concentrations of TSP and PAHs was more high in fine Particles than in coarse Particles. Both fine particles and coarse particles have negative correaltion with radiation.

• Journal of Korean Society for Atmospheric Environment
• /
• v.12 no.5
• /
• pp.567-576
• /
• 1996

Air pollution has been recognized for many years as a factor which heightens the risk of cancer. Extractable polycyclic organic matters in air particulates have been recognized as to have carcinogenic effects. This study examined the health risks posed by organic substances of air particulates in Seoul based on methodelogies that have been developed for conducting risk posed by organic substances of sir particulates in Seoul based on methodologies that have been developed for conducting risk assessment of complex -chemical-mixture. The data used in this study was obtained from air samples collected in a heavy traffic area of Seoul (Shinchon) from 1986 to 1994. The mean concentration of total supended pariculates was 158.0.mu.g/m/msup 3/, 5% of which is consisted of organic matter. The excess cancer risk from benzo(a)pyrene (BaP) was estimated to be 3.48.times.10$^{-6}$ by applying BaP unit risk estimates to the mean concentration. 8.74ng/m BaP equivalents of potency method was 1.0.times.10$^{-3}$ . The calculated risk from EOM were comparably higher than that from benzo(a)pyrene and exceeded the acceptable risk level.

• Environmental Engineering Research
• /
• v.21 no.4
• /
• pp.427-435
• /
• 2016

In this study, change in water-dissolved oxygen (DO) was analyzed under various synthetic water qualities and nanobubbles (NBs) application conditions, such as gas type, initial DO as well as water dissolved, suspended and organic matters contents. When oxygen, rather than air, was introduced into nitrogen-desorbed ultra-pure water, the stagnation time was significantly increased. It took ten days for DO concentration to drop back to saturation. The higher the initial DO concentration, the longer particles were observed above saturation due to particle stability improvement. The oxygen mass transfer rate of 0.0482 mg/L/min was found to reach a maximum at an electrolytic concentration of 0.75 g/L, beyond which the transfer rate decreased due to adsorption of negative ions of the electrolyte at the interface. High levels of turbidity caused by suspended solids have become a barrier to dissolution of NBs oxygen into the water solution, and thus affected the transfer performance. On the other hand, by applying NBs for just an hour, up to 7.2% degradation of glucose as representative organic matter was achieved. Thus, NBs technology would maintain a high DO extent for an extended duration, and thus can improve water quality provided that water chemistry is closely monitored during its application.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.667-669
• /
• 2003

A bio-optical model was developed specific for turbid and shallow waters. Special studies were carried out to estimate absorption and scattering properties as well as backscattering probability of suspended matter. The inversion of bio-optical model allows for direct retrieval of turbidity and chlorophyll- a from the visible-near infrared (VNIR) range sensor. Time-series satellite imagery from ASTER AM-1 sensor, were used to monitor the Laguna de Bay water quality condition. Spatial distribution of temperature for the lake was extracted from the thermal infrared (TIR) sensor. Corresponding field surveys were conducted to parameterize the bio -optical model. In-situ measurements include suspended particle and chlorophyll-a concentrations profiles from nephelometric devices and processing of water samples. Hyperspectral measurements were used to validate results of the bio -optical model and satellite- based estimation. This study provides a theoretical basis and a practical illustration of applying space- based measurements on an operational basis.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.19-26
• /
• 2003

The dispersion of recycled particulates in the complex coastal terrain containing Kangnung city, Korea was investigated using a three-dimensional non-hydrostatic numerical model and lagrangian particle model (or random walk model). The results show that particulates at the surface of the city that float to the top of thermal internal boundary layer (TIBL) are then transported along the eastern slope of the mountains with the passage of sea breeze and nearly reach the top of the mountains. Those particulates then disperse eastward at this upper level over the coastal sea and finally spread out over the open sea. Total suspended particulate (TSP) concentration near the surface of Kangnung city is very low. At night, synoptic scale westerly winds intensify due to the combined effect of the synoptic scale wind and land breeze descending the eastern slope of the mountains toward the coast and further seaward. This increase in speed causes development of internal gravity waves and a hydraulic jump up to a height of about 1km above the surface over the city. Particulate matter near the top of the mountains also descends the eastern slope of the mountains during the day, reaching the central city area and merges near the surface inside the nocturnal surface inversion layer (NSIL) with a maximum ground level concentration of TSP occurring at 0300 LST. Some particulates were dispersed following the propagation area of internal gravity waves and others in the NSIL are transported eastward to the coastal sea surface, aided by the land breeze. The following morning, particulates dispersed over the coastal sea from the previous night, tend to return to the coastal city of Kangnung with the sea breeze, developing a recycling process and combine with emitted surface particulates during the morning. These processes result in much higher TSP concentration. In the late morning, those particulates float to the top of the TIBL by the intrusion of the sea breeze and the ground level TSP concentration in the city subsequently decreases.

• 한국해양학회지
• /
• v.30 no.4
• /
• pp.262-270
• /
• 1995

A comparative study to understand the changes in physical and sedimentological natures was carried out in the Keum Estuary before and after the gate-close of Keum River weir. After closing of weir-gate maximum tidal current speed decreased about 30∼40% compared with that of the previous gate-opening period. Water masses also represent vertical stratifications both on water salinity and water transparency. The Keum Estuary seems to be changed from the well-mixed type estuary during the gate-opening period to the "partially-mixed type" and/or "salt-wedge type" estuary after the closing of weir-gate. The concentrations of suspended matter range 10∼100 mg/l in surface waters after the gate-close of Keum River Weir, representing about 1/4 to 1/3 decrease than those during the gate-close of Keum River Weir, representing about 1/4 to 1/3 decrease than those during the gate0opening period. Such decrease of suspended mater appears to be due to the decrease in the resuspension of bottom sediments, and also due to the vertical stratification of water masses that prevented the upward diffusion of turbid bottom waters. It is, therefore, expected that the depositional environment of Keum Estuary has been changing into the low energy conditions after the closing of weir gate, resulting in the rapid deposition of fine suspended matters within the Keum Estuary.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.231-231
• /
• 2020

Unlike conventional treatment technologies, the performance of nature-based facilities were susceptible to seasonal changes and climatological variabilities. This study evaluated the effects of seasonal variables on the treatment performance of constructed wetlands (CWs). Two CWs treating runoff and discharge from agricultural and livestock areas were monitored to determine the efficiency of the systems in reducing particulates, organics, and nutrients in the influent. For all four seasons, the mean effluent suspended solids concentration in the agricultural CW (ACW) increased by -2% to -39%. The occurrence of algal blooms in the system during summer and fall seasons resulted to the greatest increase in the amount of suspended materials in the overlying water. unlike ACW, the livestock CW (LCW) performed efficiently throughout the year, with mean suspended solids removal amounting to 61% to 68%. Algal blooms were still present in LCW seasonally; however, the constant inflow in the system limited the proliferation of phytoplankton through continuous flushing. The total nitrogen (TN) and total phosphorus (TP) removal efficiencies in ACW were higher during the summer (21% to 25%) and fall (8% to 21%) seasons since phytoplankton utilize nitrogen and phosphorus during the early stages of phytoplankton blooms. In the case of LCW, the most efficient reduction in TN (24%) and TP (54%) concentrations were also noted in summer, which can be attributed to the favorable environmental conditions for microbial activities. The mean removal of organics in ACW was lowest during summer season (-52% to 35%), wherein the onset of algal decay triggered a relative increase in organic matter and stimulate bacterial growth. The removal of organics in LCW was highest (54 % to 55%) during the fall and winter seasons since low water temperatures may limit the persistence of various algal species. Variations in environmental conditions due to seasonal changes can greatly affect the performance of CW systems. This study effectively established the contributory factors affecting the feasibility of utilizing CW systems for treating agricultural and livestock discharges and runoff.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.2
• /
• pp.206-214
• /
• 2005

This study was initiated to evaluate efficiencies of suspenced-growth processes(CAS; Conventional Activated Sludge, MLE; Modified Ludzack-Ettinger) and hybrid process(Modified-Dephanox) on removal of organic matter(C), nitrogen(N) and phosphorus(P) in municipal wastewater. M-Dephanox process was designed to improve the performance of Dephanox process on denitrification efficiency. As the results, removal efficiencies of total chemical oxygen demand(TCOD), total nitrogen(T-N) and total phosphorus(T-P) in M-Dephanox process, which is hybrid process, were 12,3, 18.6 and 28.2% higher than those in MLE, which is suspended-growth process. The better removal efficiencies of TCOD, T-N and T-P in M-Dephanox than those in MLE result that M-Dephanox is not only hybrid or multi-sludge process but also process using biosorption mechanism which is possible to use organics in denitrification, effectively. Ammonia removal efficiency in nitrification reactor of M-Dephanox was 96.7% at short hydraulic retention time(HRT) of 2 hr which was 3 hr more short HRT than that(HRT 5 hr) reported in other related papers. This indicates that M-Dephanox process can reduce HRT of whole process.

• Journal of Preventive Medicine and Public Health
• /
• v.11 no.1
• /
• pp.65-75
• /
• 1978

This study was carried out to investigate air pollution by total suspended particulate(T.S.P.), benzene soluble matter and benzo(a) pyrene in Seoul city. The sampling areas were divided into commercial(Kwang Hwa Moon), indus-trial(Ku Ro Dong) and residensial area(Shin Chon). Sampling was undertaken by High Voulme Air Sampler for four seasons from January 1917 to November 1977. The T.S.P. was extracted with Soxhlet apparatus by benzene and benzo(a) pyrene was separated by column chromatography and thin layer chromatography. The concentrations of benzo(a) pyrene were measured by means of fluorophotometer, and following results were obtained. 1. Arithmetic average concentration for 1-day averaging time of total suspended particulate were $275.6ug/m^3$ in Kwang Hwa Moon, $325.9ug/m^3$ in Ku Ro Dong and $193.0ug/m^3$ in Shin Chon. 2. The seasonal variance of total suspended parti-culate at Ku Ro Dong and Shin Chon were $102.7ug/m^3\;99.6ug/m^3$ respectively and at Kwang Hwa Moon $39.9ug/m^3$. And the concentration of autumn is higher than of that spring at Ku Ro Dong and at Shin Chon, but at Kwang Hwa Moon, the seasonal variance is very little. 3. The concentrations of 50% frequency from geometric mean for 1-day averaging time were $264ug/m^3,\;300ug/m^3\;and\;178ug/m^3$ at Kwang Hwa Moon, Ku Ro Dong and Shin Chon. And geometric standard deviation were 1.27, 1.38 and 1.41 respectively. 4. The concentrations of benzene soluble mater were $26.9ug/m^3$ at Kwang Hwa Moon, $22.7ug/m^3$ at Ku Ro Dong and $15.5ug/m^3$ at Shin Chon, and the ratios to the T.S.P. were 9.8%(range 5.6-14.8%), 7.0%(range 2.4-14.4%) and 8.0%(range 5.5-22.1%) respectively. 5. The concentrations of benzo(a) pyrene were $8.5ug/m^3$ (range $0.8-29.9ug/m^3$) at Kwang Hwa Moon $10.9ug/m^3$(range $1.1-52.0ug/m^3$) at Ku Ro Dong and $5.8ug/m^3$(range $1.5-11.4ug/m^3$) at Shin Chon. 6. The results of this investigation were relatively high in compared with the recommended standards of suspended particulate in air of U.S. Environmental Protection Agency and observed levels of benzo(a)-pyrene in U.S. city.

• Journal of the korean society of oceanography
• /
• v.34 no.2
• /
• pp.86-94
• /
• 1999

An investigation was conducted to determine limiting nutrients in the bay systems of the southern coastal area of Korea. The elemental composition of C, N, and P in suspended particulate matter was monitored nearly monthly in Chinhae and Koje Bays and seasonally in Deukryang Bay for 2 years. Atomic C:N ratio in particulate matter ranges from 4.3 to 9.6, typical of marine phytoplankton. C:P and N:P ratios vary from the Redfield ratio to 229 (C:P) and 37 (N:P). A constant C:N ratio of 6.87 from regression of particulate C and N concentrations demonstrates that the particulate matter in the systems originates from primary production. C:P and N:P ratios from regression of C on P and N on P are well associated with changes in salinity. The low N:P ratio of 13.1 implies N limitation in the environments of the systems. This seems to result from the low N:P ratio of nutrients released across sediment-water interface. Phytoplankton response, expressed here as the increase of chlorophyll a, to N addition also verifies N limitation for phytoplankton communities. In heavy rainfall season (from June to September), the addition of excessive N via streams into the stratified coastal water proliferates phytoplankton greatly. During the phytoplankton blooms, C:P and N:P ratios are much higher than the Redfield ratio, implying P limitation. This results from the high N:P ratio in nutrients supplied from stream waters. Strong stratification during the blooms also interrupts the supply of nutrients, particularly p, from bottom waters. Dependent upon precipitation, this tendency shows great inter-annual variation.